CCEffectRenderer - Fix texture coordinates for intermediate render passes from sprite sheets

We had been using the sprite's original texture coordinates for all render passes which will not
work with sprite sheets. When reading from an intermediate render target we need the texture
coordinates to be lower left (0,0) and upper right (1,1) and this is not going to be the case when
a sprite draws its image from a sprite sheet.

Fix this problem by overwriting the sprite texture coordinates with the required values when reading
from a sprite sheet.

Author: Thayer J Andrews

cocos2d/CCEffectRenderer.m

@@ -20,8 +20,19 @@
 #import "CCTexture_Private.h"
 
 
-static CCSpriteVertexes padVertices(const CCSpriteVertexes *input, CGSize padding, BOOL padVertices);
-static CCVertex padVertex(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoord1Offset, GLKVector2 texCoord2Offset);
+typedef NS_ENUM(NSUInteger, CCEffectTexCoordTransform)
+{
+    CCEffectTexCoordNoChange   = 0,
+    CCEffectTexCoordOverwrite  = 1,
+    CCEffectTexCoordPad        = 2,
+};
+
+
+static CCSpriteVertexes padVertices(const CCSpriteVertexes *input, CGSize padding, CCEffectTexCoordTransform texCoordTransform);
+static CCVertex padVertex(CCVertex input, GLKVector2 positionOffset);
+static CCVertex padVertexAndTexCoords(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoord1Offset, GLKVector2 texCoord2Offset);
+static CCVertex padVertexAndOverwriteTexCoords(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoord1, GLKVector2 texCoord2);
+
 
 @interface CCEffectRenderTarget : NSObject
 
@@ -229,8 +240,9 @@ -(void)drawSprite:(CCSprite *)sprite withEffect:(CCEffect *)effect uniforms:(NSM
         // - Later pass into FB : Pad vertices but not texture coordiates
         // - Later pass into intermediate RT : Pad vertices but not texture coordinates, add padding to RT, adjust ortho matrix
         //
+        CCEffectTexCoordTransform texCoordTransform = (fromIntermediate) ? CCEffectTexCoordOverwrite : CCEffectTexCoordPad;
 
-        renderPass.verts = padVertices(sprite.vertexes, effect.padding, !fromIntermediate);
+        renderPass.verts = padVertices(sprite.vertexes, effect.padding, texCoordTransform);
         renderPass.texCoord1Center = GLKVector2Make((sprite.vertexes->tr.texCoord1.s + sprite.vertexes->bl.texCoord1.s) * 0.5f, (sprite.vertexes->tr.texCoord1.t + sprite.vertexes->bl.texCoord1.t) * 0.5f);
         renderPass.texCoord1Extents = GLKVector2Make((sprite.vertexes->tr.texCoord1.s - sprite.vertexes->bl.texCoord1.s) * 0.5f, (sprite.vertexes->tr.texCoord1.t - sprite.vertexes->bl.texCoord1.t) * 0.5f);
         renderPass.texCoord2Center = GLKVector2Make((sprite.vertexes->tr.texCoord2.s + sprite.vertexes->bl.texCoord2.s) * 0.5f, (sprite.vertexes->tr.texCoord2.t + sprite.vertexes->bl.texCoord2.t) * 0.5f);
@@ -364,34 +376,53 @@ - (void)freeAllRenderTargets
 
 @end
 
-CCSpriteVertexes padVertices(const CCSpriteVertexes *input, CGSize padding, BOOL padTexCoords)
+CCSpriteVertexes padVertices(const CCSpriteVertexes *input, CGSize padding, CCEffectTexCoordTransform texCoordTransform)
 {
     CCSpriteVertexes output;
-    if (CGSizeEqualToSize(CGSizeZero, padding))
+    if (texCoordTransform == CCEffectTexCoordNoChange)
     {
-        output = *input;
+        output.bl = padVertex(input->bl, GLKVector2Make(-padding.width, -padding.height));
+        output.br = padVertex(input->br, GLKVector2Make( padding.width, -padding.height));
+        output.tr = padVertex(input->tr, GLKVector2Make( padding.width,  padding.height));
+        output.tl = padVertex(input->tl, GLKVector2Make(-padding.width,  padding.height));
     }
-    else
+    else if (texCoordTransform == CCEffectTexCoordOverwrite)
     {
-        GLKVector2 texCoord1Step = GLKVector2Make(0.0f, 0.0f);
-        GLKVector2 texCoord2Step = GLKVector2Make(0.0f, 0.0f);
-        if (padTexCoords)
-        {
-            texCoord1Step = GLKVector2Make(padding.width * (input->br.texCoord1.s - input->bl.texCoord1.s) / (input->br.position.x - input->bl.position.x),
-                                           padding.height * (input->tl.texCoord1.t - input->bl.texCoord1.t) / (input->tl.position.y - input->bl.position.y));
-            texCoord2Step = GLKVector2Make(padding.width * (input->br.texCoord2.s - input->bl.texCoord2.s) / (input->br.position.x - input->bl.position.x),
-                                           padding.height * (input->tl.texCoord2.t - input->bl.texCoord2.t) / (input->tl.position.y - input->bl.position.y));
-        }
+        output.bl = padVertexAndOverwriteTexCoords(input->bl, GLKVector2Make(-padding.width, -padding.height), GLKVector2Make(0.0f, 0.0f), GLKVector2Make(0.0f, 0.0f));
+        output.br = padVertexAndOverwriteTexCoords(input->br, GLKVector2Make( padding.width, -padding.height), GLKVector2Make(1.0f, 0.0f), GLKVector2Make(1.0f, 0.0f));
+        output.tr = padVertexAndOverwriteTexCoords(input->tr, GLKVector2Make( padding.width,  padding.height), GLKVector2Make(1.0f, 1.0f), GLKVector2Make(1.0f, 1.0f));
+        output.tl = padVertexAndOverwriteTexCoords(input->tl, GLKVector2Make(-padding.width,  padding.height), GLKVector2Make(0.0f, 1.0f), GLKVector2Make(0.0f, 1.0f));
+    }
+    else if (texCoordTransform == CCEffectTexCoordPad)
+    {
+        GLKVector2 texCoord1Step = GLKVector2Make(padding.width * (input->br.texCoord1.s - input->bl.texCoord1.s) / (input->br.position.x - input->bl.position.x),
+                                                  padding.height * (input->tl.texCoord1.t - input->bl.texCoord1.t) / (input->tl.position.y - input->bl.position.y));
+        GLKVector2 texCoord2Step = GLKVector2Make(padding.width * (input->br.texCoord2.s - input->bl.texCoord2.s) / (input->br.position.x - input->bl.position.x),
+                                                  padding.height * (input->tl.texCoord2.t - input->bl.texCoord2.t) / (input->tl.position.y - input->bl.position.y));
 
-        output.bl = padVertex(input->bl, GLKVector2Make(-padding.width, -padding.height), GLKVector2Make(-texCoord1Step.x, -texCoord1Step.y), GLKVector2Make(-texCoord2Step.x, -texCoord2Step.y));
-        output.br = padVertex(input->br, GLKVector2Make( padding.width, -padding.height), GLKVector2Make( texCoord1Step.x, -texCoord1Step.y), GLKVector2Make( texCoord2Step.x, -texCoord2Step.y));
-        output.tr = padVertex(input->tr, GLKVector2Make( padding.width,  padding.height), GLKVector2Make( texCoord1Step.x,  texCoord1Step.y), GLKVector2Make( texCoord2Step.x,  texCoord2Step.y));
-        output.tl = padVertex(input->tl, GLKVector2Make(-padding.width,  padding.height), GLKVector2Make(-texCoord1Step.x,  texCoord1Step.y), GLKVector2Make(-texCoord2Step.x,  texCoord2Step.y));
+        output.bl = padVertexAndTexCoords(input->bl, GLKVector2Make(-padding.width, -padding.height), GLKVector2Make(-texCoord1Step.x, -texCoord1Step.y), GLKVector2Make(-texCoord2Step.x, -texCoord2Step.y));
+        output.br = padVertexAndTexCoords(input->br, GLKVector2Make( padding.width, -padding.height), GLKVector2Make( texCoord1Step.x, -texCoord1Step.y), GLKVector2Make( texCoord2Step.x, -texCoord2Step.y));
+        output.tr = padVertexAndTexCoords(input->tr, GLKVector2Make( padding.width,  padding.height), GLKVector2Make( texCoord1Step.x,  texCoord1Step.y), GLKVector2Make( texCoord2Step.x,  texCoord2Step.y));
+        output.tl = padVertexAndTexCoords(input->tl, GLKVector2Make(-padding.width,  padding.height), GLKVector2Make(-texCoord1Step.x,  texCoord1Step.y), GLKVector2Make(-texCoord2Step.x,  texCoord2Step.y));
     }
     return output;
 }
 
-CCVertex padVertex(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoord1Offset, GLKVector2 texCoord2Offset)
+CCVertex padVertex(CCVertex input, GLKVector2 positionOffset)
+{
+    CCVertex output;
+    output.position.x = input.position.x + positionOffset.x;
+    output.position.y = input.position.y + positionOffset.y;
+    output.position.z = input.position.z;
+    output.position.w = input.position.w;
+    output.texCoord1 = input.texCoord1;
+    output.texCoord2 = input.texCoord2;
+    output.color = input.color;
+    
+    return output;
+}
+
+CCVertex padVertexAndTexCoords(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoord1Offset, GLKVector2 texCoord2Offset)
 {
     CCVertex output;
     output.position.x = input.position.x + positionOffset.x;
@@ -407,3 +438,18 @@ CCVertex padVertex(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoor
     return output;
 }
 
+CCVertex padVertexAndOverwriteTexCoords(CCVertex input, GLKVector2 positionOffset, GLKVector2 texCoord1, GLKVector2 texCoord2)
+{
+    CCVertex output;
+    output.position.x = input.position.x + positionOffset.x;
+    output.position.y = input.position.y + positionOffset.y;
+    output.position.z = input.position.z;
+    output.position.w = input.position.w;
+    output.texCoord1 = texCoord1;
+    output.texCoord2 = texCoord2;
+    output.color = input.color;
+    
+    return output;
+}
+
+