Collision data shape ordering (second attempt)

echo/Shape.hx

@@ -206,11 +206,11 @@ class Shape #if cog implements cog.IComponent #end {
 
   public function collides(s:Shape):Null<CollisionData> return null;
 
-  function collide_rect(r:Rect):Null<CollisionData> return null;
+  function collide_rect(r:Rect, flip:Bool = false):Null<CollisionData> return null;
 
-  function collide_circle(c:Circle):Null<CollisionData> return null;
+  function collide_circle(c:Circle, flip:Bool = false):Null<CollisionData> return null;
 
-  function collide_polygon(p:Polygon):Null<CollisionData> return null;
+  function collide_polygon(p:Polygon, flip:Bool = false):Null<CollisionData> return null;
 
   function toString() {
     var s = switch (type) {

echo/shape/Circle.hx

@@ -87,13 +87,13 @@ class Circle extends Shape implements Poolable {
     return false;
   }
 
-  override inline function collides(s:Shape):Null<CollisionData> return s.collide_circle(this);
+  override inline function collides(s:Shape):Null<CollisionData> return s.collide_circle(this, true);
 
-  override inline function collide_rect(r:Rect):Null<CollisionData> return r.rect_and_circle(this, true);
+  override inline function collide_rect(r:Rect, flip:Bool = false):Null<CollisionData> return r.rect_and_circle(this, !flip);
 
-  override inline function collide_circle(c:Circle):Null<CollisionData> return c.circle_and_circle(this);
+  override inline function collide_circle(c:Circle, flip:Bool = false):Null<CollisionData> return c.circle_and_circle(this, !flip);
 
-  override inline function collide_polygon(p:Polygon):Null<CollisionData> return this.circle_and_polygon(p, true);
+  override inline function collide_polygon(p:Polygon, flip:Bool = false):Null<CollisionData> return this.circle_and_polygon(p, flip);
 
   // getters
   inline function get_radius():Float return local_radius * scale_x;

echo/shape/Polygon.hx

@@ -197,13 +197,13 @@ class Polygon extends Shape implements Poolable {
     return false;
   }
 
-  override inline function collides(s:Shape):Null<CollisionData> return s.collide_polygon(this);
+  override inline function collides(s:Shape):Null<CollisionData> return s.collide_polygon(this, true);
 
-  override inline function collide_rect(r:Rect):Null<CollisionData> return r.rect_and_polygon(this, true);
+  override inline function collide_rect(r:Rect, flip:Bool = false):Null<CollisionData> return r.rect_and_polygon(this, !flip);
 
-  override inline function collide_circle(c:Circle):Null<CollisionData> return c.circle_and_polygon(this);
+  override inline function collide_circle(c:Circle, flip:Bool = false):Null<CollisionData> return c.circle_and_polygon(this, !flip);
 
-  override inline function collide_polygon(p:Polygon):Null<CollisionData> return p.polygon_and_polygon(this, true);
+  override inline function collide_polygon(p:Polygon, flip:Bool = false):Null<CollisionData> return this.polygon_and_polygon(p, flip);
 
   override inline function get_top():Float {
     if (count == 0 || vertices[0] == null) return y;

echo/shape/Rect.hx

@@ -174,13 +174,13 @@ class Rect extends Shape implements Poolable {
     return false;
   }
 
-  override inline function collides(s:Shape):Null<CollisionData> return s.collide_rect(this);
+  override inline function collides(s:Shape):Null<CollisionData> return s.collide_rect(this, true);
 
-  override inline function collide_rect(r:Rect):Null<CollisionData> return r.rect_and_rect(this);
+  override inline function collide_rect(r:Rect, flip:Bool = false):Null<CollisionData> return this.rect_and_rect(r, flip);
 
-  override inline function collide_circle(c:Circle):Null<CollisionData> return this.rect_and_circle(c);
+  override inline function collide_circle(c:Circle, flip:Bool = false):Null<CollisionData> return this.rect_and_circle(c, flip);
 
-  override inline function collide_polygon(p:Polygon):Null<CollisionData> return this.rect_and_polygon(p);
+  override inline function collide_polygon(p:Polygon, flip:Bool = false):Null<CollisionData> return this.rect_and_polygon(p, flip);
 
   override function set_parent(?body:Body) {
     super.set_parent(body);

echo/util/SAT.hx

@@ -190,17 +190,17 @@ class SAT {
     var col:CollisionData = null;
     if (rect1.rotation != 0 || rect2.rotation != 0) {
       if (rect1.transformed_rect != null) {
-        col = rect_and_polygon(rect2, rect1.transformed_rect, flip);
+        col = rect_and_polygon(rect2, rect1.transformed_rect, !flip);
 
         if (col == null) return null;
 
-        if (flip) col.sa = rect1;
+        if (flip) col.sa = rect2;
         else col.sb = rect1;
 
         return col;
       }
       if (rect2.transformed_rect != null) {
-        col = rect_and_polygon(rect1, rect2.transformed_rect, !flip);
+        col = rect_and_polygon(rect1, rect2.transformed_rect, flip);
 
         if (col == null) return null;
 
@@ -318,6 +318,7 @@ class SAT {
     data1.put();
     return data2;
   }
+
   /**
    * Test a Rect and a Circle for a Collision.
    * @param r
@@ -327,19 +328,21 @@ class SAT {
    */
   public static function rect_and_circle(r:Rect, c:Circle, flip:Bool = false):Null<CollisionData> {
     if (r.transformed_rect != null && r.rotation != 0) {
-      var col = circle_and_polygon(c, r.transformed_rect, flip);
+      var col = circle_and_polygon(c, r.transformed_rect, !flip);
 
       if (col == null) return null;
 
-      if (flip) col.sa = r;
+      // collisions used the transformed rect, set the collision data's shape back
+      // to the original rect
+      if (!flip) col.sa = r;
       else col.sb = r;
 
       return col;
     }
 
     // Vector from A to B
-    var nx = flip ? c.x - r.x : r.x - c.x;
-    var ny = flip ? c.y - r.y : r.y - c.y;
+    var nx = flip ? r.x - c.x : c.x - r.x;
+    var ny = flip ? r.y - c.y : c.y - r.y;
     // Closest point on A to center of B
     var cx = nx;
     var cy = ny;
@@ -407,6 +410,8 @@ class SAT {
 
     if (col == null) return null;
 
+    // collisions were done with a polygon derrived from the provided rect
+    // so we need to set our collision data shape back to the original rectangle
     if (flip) col.sb = r;
     else col.sa = r;
 
@@ -495,7 +500,7 @@ class SAT {
       test1 = min1 - max2;
       test2 = min2 - max1;
 
-      // Preform another test
+      // Perform another test
       if (test1 > 0 || test2 > 0) {
         col.put();
         return null;
@@ -579,7 +584,9 @@ class SAT {
     col.sa = flip ? polygon2 : polygon1;
     col.sb = flip ? polygon1 : polygon2;
 
-    if (flip) {
+    // collision normal is calculated as resolution for poly2, so we need to
+    // negate the normal if we are not flipping the collision check.
+    if (!flip) {
       col.normal.negate();
     }
 

sample/Main.hx

@@ -50,6 +50,7 @@ class Main extends BaseApp {
       PolygonState, StackingState, MultiShapeState, ShapesState, GroupsState, StaticState, LinecastState, Linecast2State, TileMapState, TileMapState2,
       BezierState, VerletState
     ];
+
     index = 0;
     // Create a State Manager and pass it the World and the first Sample
     fsm = new FSM<World>(world, Type.createInstance(sample_states[index], []));