sort out circle collision flip logic

AustinEast · Jan 16, 2024 · 04fec0d · 04fec0d
1 parent bdf99d8
commit 04fec0d
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Showing 4 changed files with 23 additions and 28 deletions.
diff --git a/echo/shape/Circle.hx b/echo/shape/Circle.hx
@@ -87,7 +87,7 @@ 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, flip:Bool = false):Null<CollisionData> return r.rect_and_circle(this, !flip);
 

diff --git a/echo/util/SAT.hx b/echo/util/SAT.hx
@@ -344,8 +344,8 @@ class SAT {
     }
 
     // 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;
@@ -506,7 +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;
@@ -529,7 +529,7 @@ class SAT {
 
     col.overlap = Math.abs(col.overlap);
 
-    if (!flip) {
+    if (flip) {
       col.normal.negate();
     }
 
@@ -590,6 +590,8 @@ class SAT {
     col.sa = flip ? polygon2 : polygon1;
     col.sb = flip ? polygon1 : polygon2;
 
+    // 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();
     }

diff --git a/sample/state/OverlappingSpawnState.hx b/sample/state/OverlappingSpawnState.hx
@@ -20,31 +20,25 @@ class OverlappingSpawnState extends BaseState {
         rotation: 0,
         material: material,
         shape: {
-				type: POLYGON,
+				type: CIRCLE,
 				radius: 16,
-				width: 16,
-				height: 16,
-				sides: 5,
 				offset_y: 0,
 			}
       });
     world.add(body);
 
-	body = new Body({
-        x: 200,
-        y: 53,
-        rotation: 0,
-        material: material,
-        shape: {
-				type: POLYGON,
-				radius: 10,
-				width: 10,
-				height: 10,
-				sides: 5,
-				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
@@ -53,7 +47,7 @@ class OverlappingSpawnState extends BaseState {
 		x: world.width / 5,
 		y: world.height - 40,
 		material: material,
-		rotation: 5,
+		// rotation: 5,
 		shape: {
 		  type: RECT,
 		  width: world.width,

diff --git a/sample/state/StaticState.hx b/sample/state/StaticState.hx
@@ -31,9 +31,8 @@ class StaticState extends BaseState {
         y: (world.height * 0.5) * Math.sin(i) + world.height * 0.5,
         material: static_material,
         shape: {
-          // type: CIRCLE,
-          // radius: Random.range(2, 4),
-          type: RECT,
+          type: CIRCLE,
+          radius: Random.range(2, 4),
           width: Random.range(2, 4),
           height: Random.range(2, 4)
         }