Phaser Source: src/physics/ninja/Circle.js

# Source: src/physics/ninja/Circle.js

    /* jshint camelcase: false */
    /**
    * @author       Richard Davey <rich@photonstorm.com>
    * @copyright    2016 Photon Storm Ltd.
    * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
    */

    /**
    * Ninja Physics Circle constructor.
    * Note: This class could be massively optimised and reduced in size. I leave that challenge up to you.
    *
    * @class Phaser.Physics.Ninja.Circle
    * @constructor
    * @param {Phaser.Physics.Ninja.Body} body - The body that owns this shape.
    * @param {number} x - The x coordinate to create this shape at.
    * @param {number} y - The y coordinate to create this shape at.
    * @param {number} radius - The radius of this Circle.
    */
    Phaser.Physics.Ninja.Circle = function (body, x, y, radius) {

        /**
        * @property {Phaser.Physics.Ninja.Body} system - A reference to the body that owns this shape.
        */
        this.body = body;

        /**
        * @property {Phaser.Physics.Ninja} system - A reference to the physics system.
        */
        this.system = body.system;

        /**
        * @property {Phaser.Point} pos - The position of this object.
        */
        this.pos = new Phaser.Point(x, y);

        /**
        * @property {Phaser.Point} oldpos - The position of this object in the previous update.
        */
        this.oldpos = new Phaser.Point(x, y);

        /**
        * @property {number} radius - The radius of this circle shape.
        */
        this.radius = radius;

        /**
        * @property {number} xw - Half the width.
        * @readonly
        */
        this.xw = radius;

        /**
        * @property {number} xw - Half the height.
        * @readonly
        */
        this.yw = radius;

        /**
        * @property {number} width - The width.
        * @readonly
        */
        this.width = radius * 2;

        /**
        * @property {number} height - The height.
        * @readonly
        */
        this.height = radius * 2;

        /**
        * @property {number} oH - Internal var.
        * @private
        */
        this.oH = 0;

        /**
        * @property {number} oV - Internal var.
        * @private
        */
        this.oV = 0;

        /**
        * @property {Phaser.Point} velocity - The velocity of this object.
        */
        this.velocity = new Phaser.Point();

        /**
        * @property {object} circleTileProjections - All of the collision response handlers.
        */
        this.circleTileProjections = {};

        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_FULL] = this.projCircle_Full;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_45DEG] = this.projCircle_45Deg;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_CONCAVE] = this.projCircle_Concave;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_CONVEX] = this.projCircle_Convex;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_22DEGs] = this.projCircle_22DegS;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_22DEGb] = this.projCircle_22DegB;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_67DEGs] = this.projCircle_67DegS;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_67DEGb] = this.projCircle_67DegB;
        this.circleTileProjections[Phaser.Physics.Ninja.Tile.TYPE_HALF] = this.projCircle_Half;

    };

    Phaser.Physics.Ninja.Circle.prototype.constructor = Phaser.Physics.Ninja.Circle;

    Phaser.Physics.Ninja.Circle.COL_NONE = 0;
    Phaser.Physics.Ninja.Circle.COL_AXIS = 1;
    Phaser.Physics.Ninja.Circle.COL_OTHER = 2;

    Phaser.Physics.Ninja.Circle.prototype = {

        /**
        * Updates this Circles position.
        *
        * @method Phaser.Physics.Ninja.Circle#integrate
        */
        integrate: function () {

            var px = this.pos.x;
            var py = this.pos.y;

            //  integrate
            this.pos.x += (this.body.drag * this.pos.x) - (this.body.drag * this.oldpos.x);
            this.pos.y += (this.body.drag * this.pos.y) - (this.body.drag * this.oldpos.y) + (this.system.gravity * this.body.gravityScale);

            //  store
            this.velocity.set(this.pos.x - px, this.pos.y - py);
            this.oldpos.set(px, py);

        },

        /**
        * Process a world collision and apply the resulting forces.
        *
        * @method Phaser.Physics.Ninja.Circle#reportCollisionVsWorld
        * @param {number} px - The tangent velocity
        * @param {number} py - The tangent velocity
        * @param {number} dx - Collision normal
        * @param {number} dy - Collision normal
        * @param {number} obj - Object this Circle collided with
        */
        reportCollisionVsWorld: function (px, py, dx, dy) {

            var p = this.pos;
            var o = this.oldpos;

            //  Calc velocity
            var vx = p.x - o.x;
            var vy = p.y - o.y;

            //  Find component of velocity parallel to collision normal
            var dp = (vx * dx + vy * dy);
            var nx = dp * dx;   //project velocity onto collision normal

            var ny = dp * dy;   //nx,ny is normal velocity

            var tx = vx - nx;   //px,py is tangent velocity
            var ty = vy - ny;

            //  We only want to apply collision response forces if the object is travelling into, and not out of, the collision
            var b, bx, by, fx, fy;

            if (dp < 0)
            {
                fx = tx * this.body.friction;
                fy = ty * this.body.friction;

                b = 1 + this.body.bounce;

                bx = (nx * b);
                by = (ny * b);

                if (dx === 1)
                {
                    this.body.touching.left = true;
                }
                else if (dx === -1)
                {
                    this.body.touching.right = true;
                }

                if (dy === 1)
                {
                    this.body.touching.up = true;
                }
                else if (dy === -1)
                {
                    this.body.touching.down = true;
                }
            }
            else
            {
                //  Moving out of collision, do not apply forces
                bx = by = fx = fy = 0;
            }

            //  Project object out of collision
            p.x += px;
            p.y += py;

            //  Apply bounce+friction impulses which alter velocity
            o.x += px + bx + fx;
            o.y += py + by + fy;

        },

        /**
        * Collides this Circle against the world bounds.
        *
        * @method Phaser.Physics.Ninja.Circle#collideWorldBounds
        */
        collideWorldBounds: function () {

            var dx = this.system.bounds.x - (this.pos.x - this.radius);

            if (0 < dx)
            {
                this.reportCollisionVsWorld(dx, 0, 1, 0, null);
            }
            else
            {
                dx = (this.pos.x + this.radius) - this.system.bounds.right;

                if (0 < dx)
                {
                    this.reportCollisionVsWorld(-dx, 0, -1, 0, null);
                }
            }

            var dy = this.system.bounds.y - (this.pos.y - this.radius);

            if (0 < dy)
            {
                this.reportCollisionVsWorld(0, dy, 0, 1, null);
            }
            else
            {
                dy = (this.pos.y + this.radius) - this.system.bounds.bottom;

                if (0 < dy)
                {
                    this.reportCollisionVsWorld(0, -dy, 0, -1, null);
                }
            }

        },

        /**
        * Collides this Circle with a Tile.
        *
        * @method Phaser.Physics.Ninja.Circle#collideCircleVsTile
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {boolean} True if they collide, otherwise false.
        */
        collideCircleVsTile: function (tile) {

            var pos = this.pos;
            var r = this.radius;
            var c = tile;

            var tx = c.pos.x;
            var ty = c.pos.y;
            var txw = c.xw;
            var tyw = c.yw;

            var dx = pos.x - tx;    //  tile->obj delta
            var px = (txw + r) - Math.abs(dx);  //  penetration depth in x

            if (0 < px)
            {
                var dy = pos.y - ty;    //  tile->obj delta
                var py = (tyw + r) - Math.abs(dy);  //  pen depth in y

                if (0 < py)
                {
                    //  object may be colliding with tile

                    //  determine grid/voronoi region of circle center
                    this.oH = 0;
                    this.oV = 0;

                    if (dx < -txw)
                    {
                        //  circle is on left side of tile
                        this.oH = -1;
                    }
                    else if (txw < dx)
                    {
                        //  circle is on right side of tile
                        this.oH = 1;
                    }

                    if (dy < -tyw)
                    {
                        //  circle is on top side of tile
                        this.oV = -1;
                    }
                    else if (tyw < dy)
                    {
                        //  circle is on bottom side of tile
                        this.oV = 1;
                    }

                    return this.resolveCircleTile(px, py, this.oH, this.oV, this, c);

                }
            }
        },

        /**
        * Resolves tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#resolveCircleTile
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        resolveCircleTile: function (x, y, oH, oV, obj, t) {

            if (0 < t.id)
            {
                return this.circleTileProjections[t.type](x, y, oH, oV, obj, t);
            }
            else
            {
                return false;
            }

        },

        /**
        * Resolves Full tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_Full
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_Full: function (x, y, oH, oV, obj, t) {

            //if we're colliding vs. the current cell, we need to project along the
            //smallest penetration vector.
            //if we're colliding vs. horiz. or vert. neighb, we simply project horiz/vert
            //if we're colliding diagonally, we need to collide vs. tile corner

            if (oH === 0)
            {
                if (oV === 0)
                {
                    //collision with current cell
                    if (x < y)
                    {
                        //penetration in x is smaller; project in x
                        var dx = obj.pos.x - t.pos.x;//get sign for projection along x-axis

                        //NOTE: should we handle the delta === 0 case?! and how? (project towards oldpos?)
                        if (dx < 0)
                        {
                            obj.reportCollisionVsWorld(-x, 0, -1, 0, t);
                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            obj.reportCollisionVsWorld(x, 0, 1, 0, t);
                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                    }
                    else
                    {
                        //penetration in y is smaller; project in y
                        var dy = obj.pos.y - t.pos.y;//get sign for projection along y-axis

                        //NOTE: should we handle the delta === 0 case?! and how? (project towards oldpos?)
                        if (dy < 0)
                        {
                            obj.reportCollisionVsWorld(0, -y, 0, -1, t);
                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            obj.reportCollisionVsWorld(0, y, 0, 1, t);
                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                    }
                }
                else
                {
                    //collision with vertical neighbor
                    obj.reportCollisionVsWorld(0, y * oV, 0, oV, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
            }
            else if (oV === 0)
            {
                //collision with horizontal neighbor
                obj.reportCollisionVsWorld(x * oH, 0, oH, 0, t);
                return Phaser.Physics.Ninja.Circle.COL_AXIS;
            }
            else
            {
                //diagonal collision

                //get diag vertex position
                var vx = t.pos.x + (oH * t.xw);
                var vy = t.pos.y + (oV * t.yw);

                var dx = obj.pos.x - vx;//calc vert->circle vector
                var dy = obj.pos.y - vy;

                var len = Math.sqrt(dx * dx + dy * dy);
                var pen = obj.radius - len;

                if (0 < pen)
                {
                    //vertex is in the circle; project outward
                    if (len === 0)
                    {
                        //project out by 45deg
                        dx = oH / Math.SQRT2;
                        dy = oV / Math.SQRT2;
                    }
                    else
                    {
                        dx /= len;
                        dy /= len;
                    }

                    obj.reportCollisionVsWorld(dx * pen, dy * pen, dx, dy, t);

                    return Phaser.Physics.Ninja.Circle.COL_OTHER;
                }
            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;

        },

        /**
        * Resolves 45 Degree tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_45Deg
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_45Deg: function (x, y, oH, oV, obj, t) {

            //if we're colliding diagonally:
            //  -if obj is in the diagonal pointed to by the slope normal: we can't collide, do nothing
            //  -else, collide vs. the appropriate vertex
            //if obj is in this tile: perform collision as for aabb-ve-45deg
            //if obj is horiz OR very neighb in direction of slope: collide only vs. slope
            //if obj is horiz or vert neigh against direction of slope: collide vs. face

            var signx = t.signx;
            var signy = t.signy;
            var lenP;

            if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current tile

                    var sx = t.sx;
                    var sy = t.sy;

                    var ox = (obj.pos.x - (sx * obj.radius)) - t.pos.x;//this gives is the coordinates of the innermost
                    var oy = (obj.pos.y - (sy * obj.radius)) - t.pos.y;//point on the circle, relative to the tile center

                    //if the dotprod of (ox,oy) and (sx,sy) is negative, the innermost point is in the slope
                    //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                    var dp = (ox * sx) + (oy * sy);

                    if (dp < 0)
                    {
                        //collision; project delta onto slope and use this as the slope penetration vector
                        sx *= -dp;//(sx,sy) is now the penetration vector
                        sy *= -dp;

                        //find the smallest axial projection vector
                        if (x < y)
                        {
                            //penetration in x is smaller
                            lenP = x;
                            y = 0;

                            //get sign for projection along x-axis
                            if ((obj.pos.x - t.pos.x) < 0)
                            {
                                x *= -1;
                            }
                        }
                        else
                        {
                            //penetration in y is smaller
                            lenP = y;
                            x = 0;

                            //get sign for projection along y-axis
                            if ((obj.pos.y - t.pos.y) < 0)
                            {
                                y *= -1;
                            }
                        }

                        var lenN = Math.sqrt(sx * sx + sy * sy);

                        if (lenP < lenN)
                        {
                            obj.reportCollisionVsWorld(x, y, x / lenP, y / lenP, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            obj.reportCollisionVsWorld(sx, sy, t.sx, t.sy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }

                }
                else
                {
                    //colliding vertically
                    if ((signy * oV) < 0)
                    {
                        //colliding with face/edge
                        obj.reportCollisionVsWorld(0, y * oV, 0, oV, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //we could only be colliding vs the slope OR a vertex
                        //look at the vector form the closest vert to the circle to decide

                        var sx = t.sx;
                        var sy = t.sy;

                        var ox = obj.pos.x - (t.pos.x - (signx * t.xw));//this gives is the coordinates of the innermost
                        var oy = obj.pos.y - (t.pos.y + (oV * t.yw));//point on the circle, relative to the closest tile vert

                        //if the component of (ox,oy) parallel to the normal's righthand normal
                        //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                        //then we project by the vertex, otherwise by the normal.
                        //note that this is simply a VERY tricky/weird method of determining
                        //if the circle is in side the slope/face's voronoi region, or that of the vertex.
                        var perp = (ox * -sy) + (oy * sx);
                        if (0 < (perp * signx * signy))
                        {
                            //collide vs. vertex
                            var len = Math.sqrt(ox * ox + oy * oy);
                            var pen = obj.radius - len;
                            if (0 < pen)
                            {
                                //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                                ox /= len;
                                oy /= len;

                                obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                        else
                        {
                            //collide vs. slope

                            //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                            //penetrating the slope. note that this method of penetration calculation doesn't hold
                            //in general (i.e it won't work if the circle is in the slope), but works in this case
                            //because we know the circle is in a neighboring cell
                            var dp = (ox * sx) + (oy * sy);
                            var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..
                            if (0 < pen)
                            {
                                //collision; circle out along normal by penetration amount
                                obj.reportCollisionVsWorld(sx * pen, sy * pen, sx, sy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                    }
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally
                if ((signx * oH) < 0)
                {
                    //colliding with face/edge
                    obj.reportCollisionVsWorld(x * oH, 0, oH, 0, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
                else
                {
                    //we could only be colliding vs the slope OR a vertex
                    //look at the vector form the closest vert to the circle to decide

                    var sx = t.sx;
                    var sy = t.sy;

                    var ox = obj.pos.x - (t.pos.x + (oH * t.xw));//this gives is the coordinates of the innermost
                    var oy = obj.pos.y - (t.pos.y - (signy * t.yw));//point on the circle, relative to the closest tile vert

                    //if the component of (ox,oy) parallel to the normal's righthand normal
                    //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                    //then we project by the normal, otherwise by the vertex.
                    //(NOTE: this is the opposite logic of the vertical case;
                    // for vertical, if the perp prod and the slope's slope agree, it's outside.
                    // for horizontal, if the perp prod and the slope's slope agree, circle is inside.
                    //  ..but this is only a property of flahs' coord system (i.e the rules might swap
                    // in righthanded systems))
                    //note that this is simply a VERY tricky/weird method of determining
                    //if the circle is in side the slope/face's voronio region, or that of the vertex.
                    var perp = (ox * -sy) + (oy * sx);
                    if ((perp * signx * signy) < 0)
                    {
                        //collide vs. vertex
                        var len = Math.sqrt(ox * ox + oy * oy);
                        var pen = obj.radius - len;
                        if (0 < pen)
                        {
                            //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                    else
                    {
                        //collide vs. slope

                        //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                        //penetrating the slope. note that this method of penetration calculation doesn't hold
                        //in general (i.e it won't work if the circle is in the slope), but works in this case
                        //because we know the circle is in a neighboring cell
                        var dp = (ox * sx) + (oy * sy);
                        var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..
                        if (0 < pen)
                        {
                            //collision; circle out along normal by penetration amount
                            obj.reportCollisionVsWorld(sx * pen, sy * pen, sx, sy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
            }
            else
            {
                //colliding diagonally
                if (0 < ((signx * oH) + (signy * oV)))
                {
                    //the dotprod of slope normal and cell offset is strictly positive,
                    //therefore obj is in the diagonal neighb pointed at by the normal, and
                    //it cannot possibly reach/touch/penetrate the slope
                    return Phaser.Physics.Ninja.Circle.COL_NONE;
                }
                else
                {
                    //collide vs. vertex
                    //get diag vertex position
                    var vx = t.pos.x + (oH * t.xw);
                    var vy = t.pos.y + (oV * t.yw);

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    var len = Math.sqrt(dx * dx + dy * dy);
                    var pen = obj.radius - len;
                    if (0 < pen)
                    {
                        //vertex is in the circle; project outward
                        if (len === 0)
                        {
                            //project out by 45deg
                            dx = oH / Math.SQRT2;
                            dy = oV / Math.SQRT2;
                        }
                        else
                        {
                            dx /= len;
                            dy /= len;
                        }

                        obj.reportCollisionVsWorld(dx * pen, dy * pen, dx, dy, t);
                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }

                }

            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;
        },

        /**
        * Resolves Concave tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_Concave
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_Concave: function (x, y, oH, oV, obj, t) {

            //if we're colliding diagonally:
            //  -if obj is in the diagonal pointed to by the slope normal: we can't collide, do nothing
            //  -else, collide vs. the appropriate vertex
            //if obj is in this tile: perform collision as for aabb
            //if obj is horiz OR very neighb in direction of slope: collide vs vert
            //if obj is horiz or vert neigh against direction of slope: collide vs. face

            var signx = t.signx;
            var signy = t.signy;
            var lenP;

            if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current tile

                    var ox = (t.pos.x + (signx * t.xw)) - obj.pos.x;//(ox,oy) is the vector from the circle to
                    var oy = (t.pos.y + (signy * t.yw)) - obj.pos.y;//tile-circle's center

                    var twid = t.xw * 2;
                    var trad = Math.sqrt(twid * twid + 0);//this gives us the radius of a circle centered on the tile's corner and extending to the opposite edge of the tile;
                    //note that this should be precomputed at compile-time since it's constant

                    var len = Math.sqrt(ox * ox + oy * oy);
                    var pen = (len + obj.radius) - trad;

                    if (0 < pen)
                    {
                        //find the smallest axial projection vector
                        if (x < y)
                        {
                            //penetration in x is smaller
                            lenP = x;
                            y = 0;

                            //get sign for projection along x-axis
                            if ((obj.pos.x - t.pos.x) < 0)
                            {
                                x *= -1;
                            }
                        }
                        else
                        {
                            //penetration in y is smaller
                            lenP = y;
                            x = 0;

                            //get sign for projection along y-axis
                            if ((obj.pos.y - t.pos.y) < 0)
                            {
                                y *= -1;
                            }
                        }

                        if (lenP < pen)
                        {
                            obj.reportCollisionVsWorld(x, y, x / lenP, y / lenP, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            //we can assume that len >0, because if we're here then
                            //(len + obj.radius) > trad, and since obj.radius <= trad
                            //len MUST be > 0
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                    else
                    {
                        return Phaser.Physics.Ninja.Circle.COL_NONE;
                    }

                }
                else
                {
                    //colliding vertically
                    if ((signy * oV) < 0)
                    {
                        //colliding with face/edge
                        obj.reportCollisionVsWorld(0, y * oV, 0, oV, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //we could only be colliding vs the vertical tip

                        //get diag vertex position
                        var vx = t.pos.x - (signx * t.xw);
                        var vy = t.pos.y + (oV * t.yw);

                        var dx = obj.pos.x - vx;//calc vert->circle vector
                        var dy = obj.pos.y - vy;

                        var len = Math.sqrt(dx * dx + dy * dy);
                        var pen = obj.radius - len;
                        if (0 < pen)
                        {
                            //vertex is in the circle; project outward
                            if (len === 0)
                            {
                                //project out vertically
                                dx = 0;
                                dy = oV;
                            }
                            else
                            {
                                dx /= len;
                                dy /= len;
                            }

                            obj.reportCollisionVsWorld(dx * pen, dy * pen, dx, dy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally
                if ((signx * oH) < 0)
                {
                    //colliding with face/edge
                    obj.reportCollisionVsWorld(x * oH, 0, oH, 0, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
                else
                {
                    //we could only be colliding vs the horizontal tip

                    //get diag vertex position
                    var vx = t.pos.x + (oH * t.xw);
                    var vy = t.pos.y - (signy * t.yw);

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    var len = Math.sqrt(dx * dx + dy * dy);
                    var pen = obj.radius - len;
                    if (0 < pen)
                    {
                        //vertex is in the circle; project outward
                        if (len === 0)
                        {
                            //project out horizontally
                            dx = oH;
                            dy = 0;
                        }
                        else
                        {
                            dx /= len;
                            dy /= len;
                        }

                        obj.reportCollisionVsWorld(dx * pen, dy * pen, dx, dy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }
                }
            }
            else
            {
                //colliding diagonally
                if (0 < ((signx * oH) + (signy * oV)))
                {
                    //the dotprod of slope normal and cell offset is strictly positive,
                    //therefore obj is in the diagonal neighb pointed at by the normal, and
                    //it cannot possibly reach/touch/penetrate the slope
                    return Phaser.Physics.Ninja.Circle.COL_NONE;
                }
                else
                {
                    //collide vs. vertex
                    //get diag vertex position
                    var vx = t.pos.x + (oH * t.xw);
                    var vy = t.pos.y + (oV * t.yw);

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    var len = Math.sqrt(dx * dx + dy * dy);
                    var pen = obj.radius - len;
                    if (0 < pen)
                    {
                        //vertex is in the circle; project outward
                        if (len === 0)
                        {
                            //project out by 45deg
                            dx = oH / Math.SQRT2;
                            dy = oV / Math.SQRT2;
                        }
                        else
                        {
                            dx /= len;
                            dy /= len;
                        }

                        obj.reportCollisionVsWorld(dx * pen, dy * pen, dx, dy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }

                }

            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;

        },

        /**
        * Resolves Convex tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_Convex
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_Convex: function (x, y, oH, oV, obj, t) {

            //if the object is horiz AND/OR vertical neighbor in the normal (signx,signy)
            //direction, collide vs. tile-circle only.
            //if we're colliding diagonally:
            //  -else, collide vs. the appropriate vertex
            //if obj is in this tile: perform collision as for aabb
            //if obj is horiz or vert neigh against direction of slope: collide vs. face

            var signx = t.signx;
            var signy = t.signy;
            var lenP;

            if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current tile

                    var ox = obj.pos.x - (t.pos.x - (signx * t.xw));//(ox,oy) is the vector from the tile-circle to
                    var oy = obj.pos.y - (t.pos.y - (signy * t.yw));//the circle's center

                    var twid = t.xw * 2;
                    var trad = Math.sqrt(twid * twid + 0);//this gives us the radius of a circle centered on the tile's corner and extending to the opposite edge of the tile;
                    //note that this should be precomputed at compile-time since it's constant

                    var len = Math.sqrt(ox * ox + oy * oy);
                    var pen = (trad + obj.radius) - len;

                    if (0 < pen)
                    {
                        //find the smallest axial projection vector
                        if (x < y)
                        {
                            //penetration in x is smaller
                            lenP = x;
                            y = 0;

                            //get sign for projection along x-axis
                            if ((obj.pos.x - t.pos.x) < 0)
                            {
                                x *= -1;
                            }
                        }
                        else
                        {
                            //penetration in y is smaller
                            lenP = y;
                            x = 0;

                            //get sign for projection along y-axis
                            if ((obj.pos.y - t.pos.y) < 0)
                            {
                                y *= -1;
                            }
                        }

                        if (lenP < pen)
                        {
                            obj.reportCollisionVsWorld(x, y, x / lenP, y / lenP, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            //note: len should NEVER be === 0, because if it is,
                            //projeciton by an axis shoudl always be shorter, and we should
                            //never arrive here
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;

                        }
                    }
                }
                else
                {
                    //colliding vertically
                    if ((signy * oV) < 0)
                    {
                        //colliding with face/edge
                        obj.reportCollisionVsWorld(0, y * oV, 0, oV, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //obj in neighboring cell pointed at by tile normal;
                        //we could only be colliding vs the tile-circle surface

                        var ox = obj.pos.x - (t.pos.x - (signx * t.xw));//(ox,oy) is the vector from the tile-circle to
                        var oy = obj.pos.y - (t.pos.y - (signy * t.yw));//the circle's center

                        var twid = t.xw * 2;
                        var trad = Math.sqrt(twid * twid + 0);//this gives us the radius of a circle centered on the tile's corner and extending to the opposite edge of the tile;
                        //note that this should be precomputed at compile-time since it's constant

                        var len = Math.sqrt(ox * ox + oy * oy);
                        var pen = (trad + obj.radius) - len;

                        if (0 < pen)
                        {

                            //note: len should NEVER be === 0, because if it is,
                            //obj is not in a neighboring cell!
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally
                if ((signx * oH) < 0)
                {
                    //colliding with face/edge
                    obj.reportCollisionVsWorld(x * oH, 0, oH, 0, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
                else
                {
                    //obj in neighboring cell pointed at by tile normal;
                    //we could only be colliding vs the tile-circle surface

                    var ox = obj.pos.x - (t.pos.x - (signx * t.xw));//(ox,oy) is the vector from the tile-circle to
                    var oy = obj.pos.y - (t.pos.y - (signy * t.yw));//the circle's center

                    var twid = t.xw * 2;
                    var trad = Math.sqrt(twid * twid + 0);//this gives us the radius of a circle centered on the tile's corner and extending to the opposite edge of the tile;
                    //note that this should be precomputed at compile-time since it's constant

                    var len = Math.sqrt(ox * ox + oy * oy);
                    var pen = (trad + obj.radius) - len;

                    if (0 < pen)
                    {

                        //note: len should NEVER be === 0, because if it is,
                        //obj is not in a neighboring cell!
                        ox /= len;
                        oy /= len;

                        obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }
                }
            }
            else
            {
                //colliding diagonally
                if (0 < ((signx * oH) + (signy * oV)))
                {
                    //obj in diag neighb cell pointed at by tile normal;
                    //we could only be colliding vs the tile-circle surface

                    var ox = obj.pos.x - (t.pos.x - (signx * t.xw));//(ox,oy) is the vector from the tile-circle to
                    var oy = obj.pos.y - (t.pos.y - (signy * t.yw));//the circle's center

                    var twid = t.xw * 2;
                    var trad = Math.sqrt(twid * twid + 0);//this gives us the radius of a circle centered on the tile's corner and extending to the opposite edge of the tile;
                    //note that this should be precomputed at compile-time since it's constant

                    var len = Math.sqrt(ox * ox + oy * oy);
                    var pen = (trad + obj.radius) - len;

                    if (0 < pen)
                    {

                        //note: len should NEVER be === 0, because if it is,
                        //obj is not in a neighboring cell!
                        ox /= len;
                        oy /= len;

                        obj.reportCollisionVsWorld(ox * pen, oy * pen, ox, oy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }
                }
                else
                {
                    //collide vs. vertex
                    //get diag vertex position
                    var vx = t.pos.x + (oH * t.xw);
                    var vy = t.pos.y + (oV * t.yw);

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    var len = Math.sqrt(dx * dx + dy * dy);
                    var pen = obj.radius - len;
                    if (0 < pen)
                    {
                        //vertex is in the circle; project outward
                        if (len === 0)
                        {
                            //project out by 45deg
                            dx = oH / Math.SQRT2;
                            dy = oV / Math.SQRT2;
                        }
                        else
                        {
                            dx /= len;
                            dy /= len;
                        }

                        obj.reportCollisionVsWorld(dx * pen, dy * pen, dx, dy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }

                }

            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;

        },

        /**
        * Resolves Half tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_Half
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_Half: function (x,y,oH,oV,obj,t) {

            //if obj is in a neighbor pointed at by the halfedge normal,
            //we'll never collide (i.e if the normal is (0,1) and the obj is in the DL.D, or R neighbors)
            //
            //if obj is in a neigbor perpendicular to the halfedge normal, it might
            //collide with the halfedge-vertex, or with the halfedge side.
            //
            //if obj is in a neigb pointing opposite the halfedge normal, obj collides with edge
            //
            //if obj is in a diagonal (pointing away from the normal), obj collides vs vertex
            //
            //if obj is in the halfedge cell, it collides as with aabb

            var signx = t.signx;
            var signy = t.signy;

            var celldp = (oH*signx + oV*signy);//this tells us about the configuration of cell-offset relative to tile normal
            if (0 < celldp)
            {
                //obj is in "far" (pointed-at-by-normal) neighbor of halffull tile, and will never hit
                return Phaser.Physics.Ninja.Circle.COL_NONE;
            }
            else if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current tile
                    var r = obj.radius;
                    var ox = (obj.pos.x - (signx*r)) - t.pos.x;//this gives is the coordinates of the innermost
                    var oy = (obj.pos.y - (signy*r)) - t.pos.y;//point on the circle, relative to the tile center

                    //we perform operations analogous to the 45deg tile, except we're using
                    //an axis-aligned slope instead of an angled one..
                    var sx = signx;
                    var sy = signy;

                    //if the dotprod of (ox,oy) and (sx,sy) is negative, the corner is in the slope
                    //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                    var dp = (ox*sx) + (oy*sy);
                    if (dp < 0)
                    {
                        //collision; project delta onto slope and use this to displace the object
                        sx *= -dp;//(sx,sy) is now the projection vector
                        sy *= -dp;

                        var lenN = Math.sqrt(sx*sx + sy*sy);
                        var lenP = Math.sqrt(x*x + y*y);

                        if (lenP < lenN)
                        {
                            obj.reportCollisionVsWorld(x,y,x/lenP, y/lenP,t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            obj.reportCollisionVsWorld(sx,sy,t.signx,t.signy);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                        return true;
                    }

                }
                else
                {
                    //colliding vertically

                    if (celldp === 0)
                    {

                        var dx = obj.pos.x - t.pos.x;

                        //we're in a cell perpendicular to the normal, and can collide vs. halfedge vertex
                        //or halfedge side
                        if ((dx*signx) < 0)
                        {
                            //collision with halfedge side
                            obj.reportCollisionVsWorld(0,y*oV,0,oV,t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            //collision with halfedge vertex
                            var dy = obj.pos.y - (t.pos.y + oV*t.yw);//(dx,dy) is now the vector from the appropriate halfedge vertex to the circle

                            var len = Math.sqrt(dx*dx + dy*dy);
                            var pen = obj.radius - len;
                            if (0 < pen)
                            {
                                //vertex is in the circle; project outward
                                if (len === 0)
                                {
                                    //project out by 45deg
                                    dx = signx / Math.SQRT2;
                                    dy = oV / Math.SQRT2;
                                }
                                else
                                {
                                    dx /= len;
                                    dy /= len;
                                }

                                obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }

                        }
                    }
                    else
                    {
                        //due to the first conditional (celldp >0), we know we're in the cell "opposite" the normal, and so
                        //we can only collide with the cell edge
                        //collision with vertical neighbor
                        obj.reportCollisionVsWorld(0,y*oV,0,oV,t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }

                }
            }
            else if (oV === 0)
            {
                //colliding horizontally
                if (celldp === 0)
                {

                    var dy = obj.pos.y - t.pos.y;

                    //we're in a cell perpendicular to the normal, and can collide vs. halfedge vertex
                    //or halfedge side
                    if ((dy*signy) < 0)
                    {
                        //collision with halfedge side
                        obj.reportCollisionVsWorld(x*oH,0,oH,0,t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //collision with halfedge vertex
                        var dx = obj.pos.x - (t.pos.x + oH*t.xw);//(dx,dy) is now the vector from the appropriate halfedge vertex to the circle

                        var len = Math.sqrt(dx*dx + dy*dy);
                        var pen = obj.radius - len;
                        if (0 < pen)
                        {
                            //vertex is in the circle; project outward
                            if (len === 0)
                            {
                                //project out by 45deg
                                dx = signx / Math.SQRT2;
                                dy = oV / Math.SQRT2;
                            }
                            else
                            {
                                dx /= len;
                                dy /= len;
                            }

                            obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }

                    }
                }
                else
                {
                    //due to the first conditional (celldp >0), we know w're in the cell "opposite" the normal, and so
                    //we can only collide with the cell edge
                    obj.reportCollisionVsWorld(x*oH, 0, oH, 0, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
            }
            else
            {
                //colliding diagonally; we know, due to the initial (celldp >0) test which has failed
                //if we've reached this point, that we're in a diagonal neighbor on the non-normal side, so
                //we could only be colliding with the cell vertex, if at all.

                //get diag vertex position
                var vx = t.pos.x + (oH*t.xw);
                var vy = t.pos.y + (oV*t.yw);

                var dx = obj.pos.x - vx;//calc vert->circle vector
                var dy = obj.pos.y - vy;

                var len = Math.sqrt(dx*dx + dy*dy);
                var pen = obj.radius - len;
                if (0 < pen)
                {
                    //vertex is in the circle; project outward
                    if (len === 0)
                    {
                        //project out by 45deg
                        dx = oH / Math.SQRT2;
                        dy = oV / Math.SQRT2;
                    }
                    else
                    {
                        dx /= len;
                        dy /= len;
                    }

                    obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                    return Phaser.Physics.Ninja.Circle.COL_OTHER;
                }

            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;

        },

        /**
        * Resolves 22 Degree tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_22DegS
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_22DegS: function (x,y,oH,oV,obj,t) {

            //if the object is in a cell pointed at by signy, no collision will ever occur
            //otherwise,
            //
            //if we're colliding diagonally:
            //  -collide vs. the appropriate vertex
            //if obj is in this tile: collide vs slope or vertex
            //if obj is horiz neighb in direction of slope: collide vs. slope or vertex
            //if obj is horiz neighb against the slope:
            //   if (distance in y from circle to 90deg corner of tile < 1/2 tileheight, collide vs. face)
            //   else(collide vs. corner of slope) (vert collision with a non-grid-aligned vert)
            //if obj is vert neighb against direction of slope: collide vs. face

            var lenP;
            var signx = t.signx;
            var signy = t.signy;

            if (0 < (signy*oV))
            {
                //object will never collide vs tile, it can't reach that far

                return Phaser.Physics.Ninja.Circle.COL_NONE;
            }
            else if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current tile
                    //we could only be colliding vs the slope OR a vertex
                    //look at the vector form the closest vert to the circle to decide

                    var sx = t.sx;
                    var sy = t.sy;

                    var r = obj.radius;
                    var ox = obj.pos.x - (t.pos.x - (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = obj.pos.y - t.pos.y;//point on the circle, relative to the tile corner

                    //if the component of (ox,oy) parallel to the normal's righthand normal
                    //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                    //then we project by the vertex, otherwise by the normal or axially.
                    //note that this is simply a VERY tricky/weird method of determining
                    //if the circle is in side the slope/face's voronio region, or that of the vertex.

                    var perp = (ox*-sy) + (oy*sx);
                    if (0 < (perp*signx*signy))
                    {
                        //collide vs. vertex
                        var len = Math.sqrt(ox*ox + oy*oy);
                        var pen = r - len;
                        if (0 < pen)
                        {
                            //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                    else
                    {
                        //collide vs. slope or vs axis
                        ox -= r*sx;//this gives us the vector from
                        oy -= r*sy;//a point on the slope to the innermost point on the circle

                        //if the dotprod of (ox,oy) and (sx,sy) is negative, the point on the circle is in the slope
                        //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                        var dp = (ox*sx) + (oy*sy);

                        if (dp < 0)
                        {
                            //collision; project delta onto slope and use this to displace the object
                            sx *= -dp;//(sx,sy) is now the projection vector
                            sy *= -dp;

                            var lenN = Math.sqrt(sx*sx + sy*sy);

                            //find the smallest axial projection vector
                            if (x < y)
                            {
                                //penetration in x is smaller
                                lenP = x;
                                y = 0;
                                //get sign for projection along x-axis
                                if ((obj.pos.x - t.pos.x) < 0)
                                {
                                    x *= -1;
                                }
                            }
                            else
                            {
                                //penetration in y is smaller
                                lenP = y;
                                x = 0;
                                //get sign for projection along y-axis
                                if ((obj.pos.y - t.pos.y)< 0)
                                {
                                    y *= -1;
                                }
                            }

                            if (lenP < lenN)
                            {
                                obj.reportCollisionVsWorld(x,y,x/lenP, y/lenP, t);

                                return Phaser.Physics.Ninja.Circle.COL_AXIS;
                            }
                            else
                            {
                                obj.reportCollisionVsWorld(sx,sy,t.sx,t.sy,t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }

                        }
                    }

                }
                else
                {
                    //colliding vertically; we can assume that (signy*oV) < 0
                    //due to the first conditional far above

                    obj.reportCollisionVsWorld(0,y*oV, 0, oV, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally
                if ((signx*oH) < 0)
                {
                    //colliding with face/edge OR with corner of wedge, depending on our position vertically

                    //collide vs. vertex
                    //get diag vertex position
                    var vx = t.pos.x - (signx*t.xw);
                    var vy = t.pos.y;

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    if ((dy*signy) < 0)
                    {
                        //colliding vs face
                        obj.reportCollisionVsWorld(x*oH, 0, oH, 0, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //colliding vs. vertex

                        var len = Math.sqrt(dx*dx + dy*dy);
                        var pen = obj.radius - len;
                        if (0 < pen)
                        {
                            //vertex is in the circle; project outward
                            if (len === 0)
                            {
                                //project out by 45deg
                                dx = oH / Math.SQRT2;
                                dy = oV / Math.SQRT2;
                            }
                            else
                            {
                                dx /= len;
                                dy /= len;
                            }

                            obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
                else
                {
                    //we could only be colliding vs the slope OR a vertex
                    //look at the vector form the closest vert to the circle to decide

                    var sx = t.sx;
                    var sy = t.sy;

                    var ox = obj.pos.x - (t.pos.x + (oH*t.xw));//this gives is the coordinates of the innermost
                    var oy = obj.pos.y - (t.pos.y - (signy*t.yw));//point on the circle, relative to the closest tile vert

                    //if the component of (ox,oy) parallel to the normal's righthand normal
                    //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                    //then we project by the normal, otherwise by the vertex.
                    //(NOTE: this is the opposite logic of the vertical case;
                    // for vertical, if the perp prod and the slope's slope agree, it's outside.
                    // for horizontal, if the perp prod and the slope's slope agree, circle is inside.
                    //  ..but this is only a property of flahs' coord system (i.e the rules might swap
                    // in righthanded systems))
                    //note that this is simply a VERY tricky/weird method of determining
                    //if the circle is in side the slope/face's voronio region, or that of the vertex.
                    var perp = (ox*-sy) + (oy*sx);
                    if ((perp*signx*signy) < 0)
                    {
                        //collide vs. vertex
                        var len = Math.sqrt(ox*ox + oy*oy);
                        var pen = obj.radius - len;
                        if (0 < pen)
                        {
                            //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                    else
                    {
                        //collide vs. slope

                        //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                        //penetrating the slope. note that this method of penetration calculation doesn't hold
                        //in general (i.e it won't work if the circle is in the slope), but works in this case
                        //because we know the circle is in a neighboring cell
                        var dp = (ox*sx) + (oy*sy);
                        var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..

                        if (0 < pen)
                        {
                            //collision; circle out along normal by penetration amount
                            obj.reportCollisionVsWorld(sx*pen, sy*pen, sx, sy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
            }
            else
            {

                //colliding diagonally; due to the first conditional above,
                //obj is vertically offset against slope, and offset in either direction horizontally

                //collide vs. vertex
                //get diag vertex position
                var vx = t.pos.x + (oH*t.xw);
                var vy = t.pos.y + (oV*t.yw);

                var dx = obj.pos.x - vx;//calc vert->circle vector
                var dy = obj.pos.y - vy;

                var len = Math.sqrt(dx*dx + dy*dy);
                var pen = obj.radius - len;
                if (0 < pen)
                {
                    //vertex is in the circle; project outward
                    if (len === 0)
                    {
                        //project out by 45deg
                        dx = oH / Math.SQRT2;
                        dy = oV / Math.SQRT2;
                    }
                    else
                    {
                        dx /= len;
                        dy /= len;
                    }

                    obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                    return Phaser.Physics.Ninja.Circle.COL_OTHER;
                }
            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;

        },

        /**
        * Resolves 22 Degree tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_22DegB
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_22DegB: function (x,y,oH, oV, obj,t) {

            //if we're colliding diagonally:
            //  -if we're in the cell pointed at by the normal, collide vs slope, else
            //  collide vs. the appropriate corner/vertex
            //
            //if obj is in this tile: collide as with aabb
            //
            //if obj is horiz or vertical neighbor AGAINST the slope: collide with edge
            //
            //if obj is horiz neighb in direction of slope: collide vs. slope or vertex or edge
            //
            //if obj is vert neighb in direction of slope: collide vs. slope or vertex

            var lenP;
            var signx = t.signx;
            var signy = t.signy;

            if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current cell

                    var sx = t.sx;
                    var sy = t.sy;

                    var r = obj.radius;
                    var ox = (obj.pos.x - (sx*r)) - (t.pos.x - (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = (obj.pos.y - (sy*r)) - (t.pos.y + (signy*t.yw));//point on the AABB, relative to a point on the slope

                    //if the dotprod of (ox,oy) and (sx,sy) is negative, the point on the circle is in the slope
                    //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                    var dp = (ox*sx) + (oy*sy);

                    if (dp < 0)
                    {
                        //collision; project delta onto slope and use this to displace the object
                        sx *= -dp;//(sx,sy) is now the projection vector
                        sy *= -dp;

                        var lenN = Math.sqrt(sx*sx + sy*sy);

                        //find the smallest axial projection vector
                        if (x < y)
                        {
                            //penetration in x is smaller
                            lenP = x;
                            y = 0;
                            //get sign for projection along x-axis
                            if ((obj.pos.x - t.pos.x) < 0)
                            {
                                x *= -1;
                            }
                        }
                        else
                        {
                            //penetration in y is smaller
                            lenP = y;
                            x = 0;
                            //get sign for projection along y-axis
                            if ((obj.pos.y - t.pos.y)< 0)
                            {
                                y *= -1;
                            }
                        }

                        if (lenP < lenN)
                        {
                            obj.reportCollisionVsWorld(x, y, x/lenP, y/lenP, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            obj.reportCollisionVsWorld(sx, sy, t.sx, t.sy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
                else
                {
                    //colliding vertically

                    if ((signy*oV) < 0)
                    {
                        //colliding with face/edge
                        obj.reportCollisionVsWorld(0, y*oV, 0, oV, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //we could only be colliding vs the slope OR a vertex
                        //look at the vector form the closest vert to the circle to decide

                        var sx = t.sx;
                        var sy = t.sy;

                        var ox = obj.pos.x - (t.pos.x - (signx*t.xw));//this gives is the coordinates of the innermost
                        var oy = obj.pos.y - (t.pos.y + (signy*t.yw));//point on the circle, relative to the closest tile vert

                        //if the component of (ox,oy) parallel to the normal's righthand normal
                        //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                        //then we project by the vertex, otherwise by the normal.
                        //note that this is simply a VERY tricky/weird method of determining
                        //if the circle is in side the slope/face's voronio region, or that of the vertex.
                        var perp = (ox*-sy) + (oy*sx);
                        if (0 < (perp*signx*signy))
                        {
                            //collide vs. vertex
                            var len = Math.sqrt(ox*ox + oy*oy);
                            var pen = obj.radius - len;
                            if (0 < pen)
                            {
                                //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                                ox /= len;
                                oy /= len;

                                obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                        else
                        {
                            //collide vs. slope

                            //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                            //penetrating the slope. note that this method of penetration calculation doesn't hold
                            //in general (i.e it won't work if the circle is in the slope), but works in this case
                            //because we know the circle is in a neighboring cell
                            var dp = (ox*sx) + (oy*sy);
                            var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..
                            if (0 < pen)
                            {
                                //collision; circle out along normal by penetration amount
                                obj.reportCollisionVsWorld(sx*pen, sy*pen,sx, sy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                    }
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally

                if ((signx*oH) < 0)
                {
                    //colliding with face/edge
                    obj.reportCollisionVsWorld(x*oH, 0, oH, 0, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
                else
                {
                    //colliding with edge, slope, or vertex

                    var ox = obj.pos.x - (t.pos.x + (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = obj.pos.y - t.pos.y;//point on the circle, relative to the closest tile vert

                    if ((oy*signy) < 0)
                    {
                        //we're colliding with the halfface
                        obj.reportCollisionVsWorld(x*oH, 0, oH, 0, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //colliding with the vertex or slope

                        var sx = t.sx;
                        var sy = t.sy;

                        //if the component of (ox,oy) parallel to the normal's righthand normal
                        //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                        //then we project by the slope, otherwise by the vertex.
                        //note that this is simply a VERY tricky/weird method of determining
                        //if the circle is in side the slope/face's voronio region, or that of the vertex.
                        var perp = (ox*-sy) + (oy*sx);
                        if ((perp*signx*signy) < 0)
                        {
                            //collide vs. vertex
                            var len = Math.sqrt(ox*ox + oy*oy);
                            var pen = obj.radius - len;
                            if (0 < pen)
                            {
                                //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                                ox /= len;
                                oy /= len;

                                obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                        else
                        {
                            //collide vs. slope

                            //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                            //penetrating the slope. note that this method of penetration calculation doesn't hold
                            //in general (i.e it won't work if the circle is in the slope), but works in this case
                            //because we know the circle is in a neighboring cell
                            var dp = (ox*sx) + (oy*sy);
                            var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..
                            if (0 < pen)
                            {
                                //collision; circle out along normal by penetration amount
                                obj.reportCollisionVsWorld(sx*pen, sy*pen, t.sx, t.sy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                    }
                }
            }
            else
            {
                //colliding diagonally
                if ( 0 < ((signx*oH) + (signy*oV)) )
                {
                    //the dotprod of slope normal and cell offset is strictly positive,
                    //therefore obj is in the diagonal neighb pointed at by the normal.

                    //collide vs slope

                    //we should really precalc this at compile time, but for now, fuck it
                    var slen = Math.sqrt(2*2 + 1*1);//the raw slope is (-2,-1)
                    var sx = (signx*1) / slen;//get slope _unit_ normal;
                    var sy = (signy*2) / slen;//raw RH normal is (1,-2)

                    var r = obj.radius;
                    var ox = (obj.pos.x - (sx*r)) - (t.pos.x - (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = (obj.pos.y - (sy*r)) - (t.pos.y + (signy*t.yw));//point on the circle, relative to a point on the slope

                    //if the dotprod of (ox,oy) and (sx,sy) is negative, the point on the circle is in the slope
                    //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                    var dp = (ox*sx) + (oy*sy);

                    if (dp < 0)
                    {
                        //collision; project delta onto slope and use this to displace the object
                        //(sx,sy)*-dp is the projection vector
                        obj.reportCollisionVsWorld(-sx*dp, -sy*dp, t.sx, t.sy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }
                    return Phaser.Physics.Ninja.Circle.COL_NONE;
                }
                else
                {
                    //collide vs the appropriate vertex
                    var vx = t.pos.x + (oH*t.xw);
                    var vy = t.pos.y + (oV*t.yw);

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    var len = Math.sqrt(dx*dx + dy*dy);
                    var pen = obj.radius - len;
                    if (0 < pen)
                    {
                        //vertex is in the circle; project outward
                        if (len === 0)
                        {
                            //project out by 45deg
                            dx = oH / Math.SQRT2;
                            dy = oV / Math.SQRT2;
                        }
                        else
                        {
                            dx /= len;
                            dy /= len;
                        }

                        obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }

                }
            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;
        },

        /**
        * Resolves 67 Degree tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_67DegS
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_67DegS: function (x,y,oH,oV,obj,t) {

            //if the object is in a cell pointed at by signx, no collision will ever occur
            //otherwise,
            //
            //if we're colliding diagonally:
            //  -collide vs. the appropriate vertex
            //if obj is in this tile: collide vs slope or vertex or axis
            //if obj is vert neighb in direction of slope: collide vs. slope or vertex
            //if obj is vert neighb against the slope:
            //   if (distance in y from circle to 90deg corner of tile < 1/2 tileheight, collide vs. face)
            //   else(collide vs. corner of slope) (vert collision with a non-grid-aligned vert)
            //if obj is horiz neighb against direction of slope: collide vs. face

            var signx = t.signx;
            var signy = t.signy;

            if (0 < (signx*oH))
            {
                //object will never collide vs tile, it can't reach that far

                return Phaser.Physics.Ninja.Circle.COL_NONE;
            }
            else if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current tile
                    //we could only be colliding vs the slope OR a vertex
                    //look at the vector form the closest vert to the circle to decide

                    var lenP;
                    var sx = t.sx;
                    var sy = t.sy;

                    var r = obj.radius;
                    var ox = obj.pos.x - t.pos.x;//this gives is the coordinates of the innermost
                    var oy = obj.pos.y - (t.pos.y - (signy*t.yw));//point on the circle, relative to the tile corner

                    //if the component of (ox,oy) parallel to the normal's righthand normal
                    //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                    //then we project by the normal or axis, otherwise by the corner/vertex
                    //note that this is simply a VERY tricky/weird method of determining
                    //if the circle is in side the slope/face's voronoi region, or that of the vertex.

                    var perp = (ox*-sy) + (oy*sx);
                    if ((perp*signx*signy) < 0)
                    {
                        //collide vs. vertex
                        var len = Math.sqrt(ox*ox + oy*oy);
                        var pen = r - len;
                        if (0 < pen)
                        {
                            //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);
                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                    else
                    {
                        //collide vs. slope or vs axis
                        ox -= r*sx;//this gives us the vector from
                        oy -= r*sy;//a point on the slope to the innermost point on the circle

                        //if the dotprod of (ox,oy) and (sx,sy) is negative, the point on the circle is in the slope
                        //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                        var dp = (ox*sx) + (oy*sy);

                        if (dp < 0)
                        {
                            //collision; project delta onto slope and use this to displace the object
                            sx *= -dp;//(sx,sy) is now the projection vector
                            sy *= -dp;

                            var lenN = Math.sqrt(sx*sx + sy*sy);

                            //find the smallest axial projection vector
                            if (x < y)
                            {
                                //penetration in x is smaller
                                lenP = x;
                                y = 0;
                                //get sign for projection along x-axis
                                if ((obj.pos.x - t.pos.x) < 0)
                                {
                                    x *= -1;
                                }
                            }
                            else
                            {
                                //penetration in y is smaller
                                lenP = y;
                                x = 0;
                                //get sign for projection along y-axis
                                if ((obj.pos.y - t.pos.y)< 0)
                                {
                                    y *= -1;
                                }
                            }

                            if (lenP < lenN)
                            {
                                obj.reportCollisionVsWorld(x,y,x/lenP, y/lenP, t);

                                return Phaser.Physics.Ninja.Circle.COL_AXIS;
                            }
                            else
                            {
                                obj.reportCollisionVsWorld(sx,sy,t.sx,t.sy,t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                    }

                }
                else
                {
                    //colliding vertically

                    if ((signy*oV) < 0)
                    {
                        //colliding with face/edge OR with corner of wedge, depending on our position vertically

                        //collide vs. vertex
                        //get diag vertex position
                        var vx = t.pos.x;
                        var vy = t.pos.y - (signy*t.yw);

                        var dx = obj.pos.x - vx;//calc vert->circle vector
                        var dy = obj.pos.y - vy;

                        if ((dx*signx) < 0)
                        {
                            //colliding vs face
                            obj.reportCollisionVsWorld(0, y*oV, 0, oV, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            //colliding vs. vertex

                            var len = Math.sqrt(dx*dx + dy*dy);
                            var pen = obj.radius - len;
                            if (0 < pen)
                            {
                                //vertex is in the circle; project outward
                                if (len === 0)
                                {
                                    //project out by 45deg
                                    dx = oH / Math.SQRT2;
                                    dy = oV / Math.SQRT2;
                                }
                                else
                                {
                                    dx /= len;
                                    dy /= len;
                                }

                                obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                    }
                    else
                    {
                        //we could only be colliding vs the slope OR a vertex
                        //look at the vector form the closest vert to the circle to decide

                        var sx = t.sx;
                        var sy = t.sy;

                        var ox = obj.pos.x - (t.pos.x - (signx*t.xw));//this gives is the coordinates of the innermost
                        var oy = obj.pos.y - (t.pos.y + (oV*t.yw));//point on the circle, relative to the closest tile vert

                        //if the component of (ox,oy) parallel to the normal's righthand normal
                        //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                        //then we project by the vertex, otherwise by the normal.
                        //note that this is simply a VERY tricky/weird method of determining
                        //if the circle is in side the slope/face's voronio region, or that of the vertex.
                        var perp = (ox*-sy) + (oy*sx);
                        if (0 < (perp*signx*signy))
                        {
                            //collide vs. vertex
                            var len = Math.sqrt(ox*ox + oy*oy);
                            var pen = obj.radius - len;
                            if (0 < pen)
                            {
                                //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                                ox /= len;
                                oy /= len;

                                obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                        else
                        {
                            //collide vs. slope

                            //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                            //penetrating the slope. note that this method of penetration calculation doesn't hold
                            //in general (i.e it won't work if the circle is in the slope), but works in this case
                            //because we know the circle is in a neighboring cell
                            var dp = (ox*sx) + (oy*sy);
                            var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..

                            if (0 < pen)
                            {
                                //collision; circle out along normal by penetration amount
                                obj.reportCollisionVsWorld(sx*pen, sy*pen, t.sx, t.sy, t);

                                return Phaser.Physics.Ninja.Circle.COL_OTHER;
                            }
                        }
                    }
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally; we can assume that (signy*oV) < 0
                //due to the first conditional far above

                obj.reportCollisionVsWorld(x*oH, 0, oH, 0, t);

                return Phaser.Physics.Ninja.Circle.COL_AXIS;
            }
            else
            {
                //colliding diagonally; due to the first conditional above,
                //obj is vertically offset against slope, and offset in either direction horizontally

                //collide vs. vertex
                //get diag vertex position
                var vx = t.pos.x + (oH*t.xw);
                var vy = t.pos.y + (oV*t.yw);

                var dx = obj.pos.x - vx;//calc vert->circle vector
                var dy = obj.pos.y - vy;

                var len = Math.sqrt(dx*dx + dy*dy);
                var pen = obj.radius - len;
                if (0 < pen)
                {
                    //vertex is in the circle; project outward
                    if (len === 0)
                    {
                        //project out by 45deg
                        dx = oH / Math.SQRT2;
                        dy = oV / Math.SQRT2;
                    }
                    else
                    {
                        dx /= len;
                        dy /= len;
                    }

                    obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                    return Phaser.Physics.Ninja.Circle.COL_OTHER;
                }
            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;

        },

        /**
        * Resolves 67 Degree tile collision.
        *
        * @method Phaser.Physics.Ninja.Circle#projCircle_67DegB
        * @param {number} x - Penetration depth on the x axis.
        * @param {number} y - Penetration depth on the y axis.
        * @param {number} oH - Grid / voronoi region.
        * @param {number} oV - Grid / voronoi region.
        * @param {Phaser.Physics.Ninja.Circle} obj - The Circle involved in the collision.
        * @param {Phaser.Physics.Ninja.Tile} t - The Tile involved in the collision.
        * @return {number} The result of the collision.
        */
        projCircle_67DegB: function (x,y,oH, oV, obj,t) {

            //if we're colliding diagonally:
            //  -if we're in the cell pointed at by the normal, collide vs slope, else
            //  collide vs. the appropriate corner/vertex
            //
            //if obj is in this tile: collide as with aabb
            //
            //if obj is horiz or vertical neighbor AGAINST the slope: collide with edge
            //
            //if obj is vert neighb in direction of slope: collide vs. slope or vertex or halfedge
            //
            //if obj is horiz neighb in direction of slope: collide vs. slope or vertex

            var signx = t.signx;
            var signy = t.signy;

            if (oH === 0)
            {
                if (oV === 0)
                {
                    //colliding with current cell

                    var lenP;
                    var sx = t.sx;
                    var sy = t.sy;

                    var r = obj.radius;
                    var ox = (obj.pos.x - (sx*r)) - (t.pos.x + (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = (obj.pos.y - (sy*r)) - (t.pos.y - (signy*t.yw));//point on the AABB, relative to a point on the slope

                    //if the dotprod of (ox,oy) and (sx,sy) is negative, the point on the circle is in the slope
                    //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                    var dp = (ox*sx) + (oy*sy);

                    if (dp < 0)
                    {
                        //collision; project delta onto slope and use this to displace the object
                        sx *= -dp;//(sx,sy) is now the projection vector
                        sy *= -dp;

                        var lenN = Math.sqrt(sx*sx + sy*sy);

                        //find the smallest axial projection vector
                        if (x < y)
                        {
                            //penetration in x is smaller
                            lenP = x;
                            y = 0;
                            //get sign for projection along x-axis
                            if ((obj.pos.x - t.pos.x) < 0)
                            {
                                x *= -1;
                            }
                        }
                        else
                        {
                            //penetration in y is smaller
                            lenP = y;
                            x = 0;
                            //get sign for projection along y-axis
                            if ((obj.pos.y - t.pos.y)< 0)
                            {
                                y *= -1;
                            }
                        }

                        if (lenP < lenN)
                        {
                            obj.reportCollisionVsWorld(x,y,x/lenP, y/lenP, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            obj.reportCollisionVsWorld(sx, sy, t.sx, t.sy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }

                    }
                }
                else
                {
                    //colliding vertically

                    if ((signy*oV) < 0)
                    {
                        //colliding with face/edge
                        obj.reportCollisionVsWorld(0, y*oV, 0, oV, t);

                        return Phaser.Physics.Ninja.Circle.COL_AXIS;
                    }
                    else
                    {
                        //colliding with edge, slope, or vertex

                        var ox = obj.pos.x - t.pos.x;//this gives is the coordinates of the innermost
                        var oy = obj.pos.y - (t.pos.y + (signy*t.yw));//point on the circle, relative to the closest tile vert

                        if ((ox*signx) < 0)
                        {
                            //we're colliding with the halfface
                            obj.reportCollisionVsWorld(0, y*oV, 0, oV, t);

                            return Phaser.Physics.Ninja.Circle.COL_AXIS;
                        }
                        else
                        {
                            //colliding with the vertex or slope

                            var sx = t.sx;
                            var sy = t.sy;

                            //if the component of (ox,oy) parallel to the normal's righthand normal
                            //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                            //then we project by the vertex, otherwise by the slope.
                            //note that this is simply a VERY tricky/weird method of determining
                            //if the circle is in side the slope/face's voronio region, or that of the vertex.
                            var perp = (ox*-sy) + (oy*sx);
                            if (0 < (perp*signx*signy))
                            {
                                //collide vs. vertex
                                var len = Math.sqrt(ox*ox + oy*oy);
                                var pen = obj.radius - len;
                                if (0 < pen)
                                {
                                    //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                                    ox /= len;
                                    oy /= len;

                                    obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                                    return Phaser.Physics.Ninja.Circle.COL_OTHER;
                                }
                            }
                            else
                            {
                                //collide vs. slope

                                //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                                //penetrating the slope. note that this method of penetration calculation doesn't hold
                                //in general (i.e it won't work if the circle is in the slope), but works in this case
                                //because we know the circle is in a neighboring cell
                                var dp = (ox*sx) + (oy*sy);
                                var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..
                                if (0 < pen)
                                {
                                    //collision; circle out along normal by penetration amount
                                    obj.reportCollisionVsWorld(sx*pen, sy*pen, sx, sy, t);

                                    return Phaser.Physics.Ninja.Circle.COL_OTHER;
                                }
                            }
                        }
                    }
                }
            }
            else if (oV === 0)
            {
                //colliding horizontally

                if ((signx*oH) < 0)
                {
                    //colliding with face/edge
                    obj.reportCollisionVsWorld(x*oH, 0, oH, 0, t);

                    return Phaser.Physics.Ninja.Circle.COL_AXIS;
                }
                else
                {
                    //we could only be colliding vs the slope OR a vertex
                    //look at the vector form the closest vert to the circle to decide

                    var slen = Math.sqrt(2*2 + 1*1);//the raw slope is (-2,-1)
                    var sx = (signx*2) / slen;//get slope _unit_ normal;
                    var sy = (signy*1) / slen;//raw RH normal is (1,-2)

                    var ox = obj.pos.x - (t.pos.x + (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = obj.pos.y - (t.pos.y - (signy*t.yw));//point on the circle, relative to the closest tile vert

                    //if the component of (ox,oy) parallel to the normal's righthand normal
                    //has the same sign as the slope of the slope (the sign of the slope's slope is signx*signy)
                    //then we project by the slope, otherwise by the vertex.
                    //note that this is simply a VERY tricky/weird method of determining
                    //if the circle is in side the slope/face's voronio region, or that of the vertex.
                    var perp = (ox*-sy) + (oy*sx);
                    if ((perp*signx*signy) < 0)
                    {
                        //collide vs. vertex
                        var len = Math.sqrt(ox*ox + oy*oy);
                        var pen = obj.radius - len;
                        if (0 < pen)
                        {
                            //note: if len=0, then perp=0 and we'll never reach here, so don't worry about div-by-0
                            ox /= len;
                            oy /= len;

                            obj.reportCollisionVsWorld(ox*pen, oy*pen, ox, oy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                    else
                    {
                        //collide vs. slope

                        //if the component of (ox,oy) parallel to the normal is less than the circle radius, we're
                        //penetrating the slope. note that this method of penetration calculation doesn't hold
                        //in general (i.e it won't work if the circle is in the slope), but works in this case
                        //because we know the circle is in a neighboring cell
                        var dp = (ox*sx) + (oy*sy);
                        var pen = obj.radius - Math.abs(dp);//note: we don't need the abs because we know the dp will be positive, but just in case..
                        if (0 < pen)
                        {
                            //collision; circle out along normal by penetration amount
                            obj.reportCollisionVsWorld(sx*pen, sy*pen, t.sx, t.sy, t);

                            return Phaser.Physics.Ninja.Circle.COL_OTHER;
                        }
                    }
                }
            }
            else
            {
                //colliding diagonally
                if ( 0 < ((signx*oH) + (signy*oV)) )
                {
                    //the dotprod of slope normal and cell offset is strictly positive,
                    //therefore obj is in the diagonal neighb pointed at by the normal.

                    //collide vs slope

                    var sx = t.sx;
                    var sy = t.sy;

                    var r = obj.radius;
                    var ox = (obj.pos.x - (sx*r)) - (t.pos.x + (signx*t.xw));//this gives is the coordinates of the innermost
                    var oy = (obj.pos.y - (sy*r)) - (t.pos.y - (signy*t.yw));//point on the circle, relative to a point on the slope

                    //if the dotprod of (ox,oy) and (sx,sy) is negative, the point on the circle is in the slope
                    //and we need toproject it out by the magnitude of the projection of (ox,oy) onto (sx,sy)
                    var dp = (ox*sx) + (oy*sy);

                    if (dp < 0)
                    {
                        //collision; project delta onto slope and use this to displace the object
                        //(sx,sy)*-dp is the projection vector

                        obj.reportCollisionVsWorld(-sx*dp, -sy*dp, t.sx, t.sy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }
                    return Phaser.Physics.Ninja.Circle.COL_NONE;
                }
                else
                {

                    //collide vs the appropriate vertex
                    var vx = t.pos.x + (oH*t.xw);
                    var vy = t.pos.y + (oV*t.yw);

                    var dx = obj.pos.x - vx;//calc vert->circle vector
                    var dy = obj.pos.y - vy;

                    var len = Math.sqrt(dx*dx + dy*dy);
                    var pen = obj.radius - len;
                    if (0 < pen)
                    {
                        //vertex is in the circle; project outward
                        if (len === 0)
                        {
                            //project out by 45deg
                            dx = oH / Math.SQRT2;
                            dy = oV / Math.SQRT2;
                        }
                        else
                        {
                            dx /= len;
                            dy /= len;
                        }

                        obj.reportCollisionVsWorld(dx*pen, dy*pen, dx, dy, t);

                        return Phaser.Physics.Ninja.Circle.COL_OTHER;
                    }

                }
            }

            return Phaser.Physics.Ninja.Circle.COL_NONE;
        },

        /**
        * Destroys this Circle's reference to Body and System
        *
        * @method Phaser.Physics.Ninja.Circle#destroy
        */
        destroy: function() {
            this.body = null;
            this.system = null;
        },

        /**
        * Render this circle for debugging purposes.
        *
        * @method Phaser.Physics.Ninja.Circle#render
        * @param {object} context - The context to render to.
        * @param {number} xOffset - X offset from circle's position to render at.
        * @param {number} yOffset - Y offset from circle's position to render at.
        * @param {string} color - color of the debug shape to be rendered. (format is css color string).
        * @param {boolean} filled - Render the shape as solid (true) or hollow (false).
        */
        render: function(context, xOffset, yOffset, color, filled) {
            var x = this.pos.x - xOffset;
            var y = this.pos.y - yOffset;

            context.beginPath();
            context.arc(x, y, this.radius, 0, 2 * Math.PI, false);

            if (filled)
            {
                context.fillStyle = color;
                context.fill();
            }
            else
            {
                context.strokeStyle = color;
                context.stroke();
            }
        }
    };