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 +328,24 @@ 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;
-      else col.sb = 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;
@@ -407,8 +413,13 @@ class SAT {
 
     if (col == null) return null;
 
-    if (flip) col.sb = r;
-    else col.sa = r;
+    // 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;
+    }
 
     return col;
   }
@@ -495,7 +506,7 @@ class SAT {
       test1 = min1 - max2;
       test2 = min2 - max1;
 
-      // Preform another test
+      // Preform another test // TODO: What is this test doing, exactly?
       if (test1 > 0 || test2 > 0) {
         col.put();
         return null;
@@ -579,7 +590,9 @@ 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

@@ -46,7 +46,7 @@ class Main extends BaseApp {
 
     // Set up our Sample States
     sample_states = [
-      PolygonState, StackingState, MultiShapeState, ShapesState, GroupsState, StaticState, LinecastState, Linecast2State, TileMapState, TileMapState2,
+      OverlappingSpawnState, ListenerState, PolygonState, StackingState, MultiShapeState, ShapesState, GroupsState, StaticState, LinecastState, Linecast2State, TileMapState, TileMapState2,
       BezierState, VerletState
     ];
     index = 0;

sample/state/ListenerState.hx

@@ -0,0 +1,82 @@
+package state;
+
+import echo.data.Options.ListenerOptions;
+import echo.Material;
+import echo.Body;
+import echo.World;
+import util.Random;
+
+class ListenerState extends BaseState {
+
+  override public function enter(world:World) {
+    Main.instance.state_text.text = "Sample: Collision Listener";
+
+    // Create a material for all the shapes to share
+    var material:Material = {elasticity: 0.7};
+
+    var bodyA = new Body({
+        x: Random.range(60, world.width - 60),
+        y: Random.range(0, world.height / 2),
+        // rotation: Random.range(0, 360),
+        material: material,
+        shapes: [
+			{
+				type: POLYGON,
+				radius: Random.range(16, 32),
+				width: Random.range(16, 48),
+				height: Random.range(16, 48),
+				sides: Random.range_int(3, 8),
+				offset_y: -10,
+			},
+			{
+				type: POLYGON,
+				radius: Random.range(16, 32),
+				width: Random.range(16, 48),
+				height: Random.range(16, 48),
+				sides: Random.range_int(3, 8),
+				offset_y: 10,
+			}
+		]
+      });
+    world.add(bodyA);
+
+    // Add a Physics body at the bottom of the screen for the other Physics Bodies to stack on top of
+    // This body has a mass of 0, so it acts as an immovable object
+	var bodyB = new Body({
+		mass: STATIC,
+		x: world.width / 5,
+		y: world.height - 40,
+		material: material,
+		rotation: 5,
+		shape: {
+		  type: RECT,
+		  width: world.width,
+		  height: 20
+		}
+	  });
+    world.add(bodyB);
+
+    var dbgOpts:ListenerOptions = {
+      enter: (a, b, data) -> {
+		trace('bodyA == listener `a`: ${bodyA == a}');
+		// the second shape is our 'bottom' shape that is making the collision
+		trace('bodyA owns data `shape a`: ${bodyA.shapes.contains(data[0].sa)}');
+		trace('bodyB == listener `b`: ${bodyB == b}');
+		trace('bodyB owns `shape b`: ${bodyB.shapes.contains(data[0].sb)}');
+      },
+    };
+
+    // Create a listener for collisions between the Physics Bodies
+    world.listen(bodyA, bodyB, dbgOpts);
+  }
+
+  override function step(world:World, dt:Float) {
+    // Reset any off-screen Bodies
+    world.for_each((member) -> {
+      if (offscreen(member, world)) {
+        member.velocity.set(0, 0);
+        member.set_position(Random.range(0, world.width), 0);
+      }
+    });
+  }
+}

sample/state/OverlappingSpawnState.hx

@@ -0,0 +1,72 @@
+package state;
+
+import echo.data.Options.ListenerOptions;
+import echo.Material;
+import echo.Body;
+import echo.World;
+import util.Random;
+
+class OverlappingSpawnState extends BaseState {
+
+  override public function enter(world:World) {
+    Main.instance.state_text.text = "Sample: Collision Listener";
+
+    // Create a material for all the shapes to share
+    var material:Material = {elasticity: 0.7};
+
+    var body = new Body({
+        x: 200,
+        y: 50,
+        rotation: 0,
+        material: material,
+        shape: {
+				type: CIRCLE,
+				radius: 16,
+				offset_y: 0,
+			}
+      });
+    world.add(body);
+
+	// body = new Body({
+  //       x: 200,
+  //       y: 53,
+  //       rotation: 0,
+  //       material: material,
+  //       shape: {
+	// 			type: CIRCLE,
+  //       radius: 12,
+	// 			offset_y: 0,
+	// 		}
+  //     });
+  //   world.add(body);
+
+    // Add a Physics body at the bottom of the screen for the other Physics Bodies to stack on top of
+    // This body has a mass of 0, so it acts as an immovable object
+	var floor = new Body({
+		mass: STATIC,
+		x: world.width / 5,
+		y: world.height - 40,
+		material: material,
+		// rotation: 5,
+		shape: {
+		  type: RECT,
+		  width: world.width,
+		  height: 20
+		}
+	  });
+    world.add(floor);
+
+    // Create a listener for collisions between the Physics Bodies
+    world.listen();
+  }
+
+  override function step(world:World, dt:Float) {
+    // Reset any off-screen Bodies
+    world.for_each((member) -> {
+      if (offscreen(member, world)) {
+        member.velocity.set(0, 0);
+        member.set_position(Random.range(0, world.width), 0);
+      }
+    });
+  }
+}

sample/state/PolygonState.hx

@@ -21,7 +21,7 @@ class PolygonState extends BaseState {
       var b = new Body({
         x: Random.range(60, world.width - 60),
         y: Random.range(0, world.height / 2),
-        rotation: Random.range(0, 360),
+        rotation: 0,
         material: material,
         shape: {
           type: POLYGON,

sample/state/StaticState.hx

@@ -33,6 +33,8 @@ class StaticState extends BaseState {
         shape: {
           type: CIRCLE,
           radius: Random.range(2, 4),
+          width: Random.range(2, 4),
+          height: Random.range(2, 4)
         }
       });
       world.add(b);