CCEffectReflection - Fix NDC to world space computation

Instead of calculating this within the effect, calculate it in the effect renderer. The math is dependent
on whether or not we're rendering directly to the screen or to an intermediate render target and we
want to hide that from effects.

Author: Thayer J Andrews

cocos2d/CCEffectReflection.m

@@ -15,7 +15,6 @@
 #import "CCTexture.h"
 
 #import "CCEffect_Private.h"
-#import "CCRenderer_Private.h"
 #import "CCSprite_Private.h"
 
 
@@ -196,9 +195,6 @@ -(void)buildRenderPasses
 
         pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_envMap"]] = weakSelf.environment.texture ?: [CCTexture none];
 
-        CGFloat scale = [CCDirector sharedDirector].contentScaleFactor;
-        CGAffineTransform screenToWorld = CGAffineTransformMake(1.0f / scale, 0.0f, 0.0f, 1.0f / scale, 0.0f, 0.0f);
-        
         // Get the transform from world space to environment texture space. This is
         // concatenated with the current transform to move from local node space to
         // environment texture space.
@@ -213,12 +209,9 @@ -(void)buildRenderPasses
 
         // Setup the transform from normalized device coordinates (NDC, which is the space our vertex
         // positions are in) to environment texture space. We use this to compute environment texture
-        // coordinates in the vertex shader.
-        GLKMatrix4 ndcToWorldMat;
-        [pass.renderer.globalShaderUniforms[CCShaderUniformProjectionInv] getValue:&ndcToWorldMat];
-        
+        // coordinates in the vertex shader.s
         GLKMatrix4 worldToReflectEnvTextureMat = CCEffectUtilsMat4FromAffineTransform(worldToReflectEnvTexture);
-        GLKMatrix4 ndcToReflectEnvTextureMat = GLKMatrix4Multiply(worldToReflectEnvTextureMat, ndcToWorldMat);
+        GLKMatrix4 ndcToReflectEnvTextureMat = GLKMatrix4Multiply(worldToReflectEnvTextureMat, pass.ndcToWorld);
 
         pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_ndcToEnv"]] = [NSValue valueWithGLKMatrix4:ndcToReflectEnvTextureMat];
 

cocos2d/CCEffectRenderer.m

@@ -15,6 +15,7 @@
 #import "ccUtils.h"
 
 #import "CCEffect_Private.h"
+#import "CCRenderer_Private.h"
 #import "CCSprite_Private.h"
 #import "CCTexture_Private.h"
 
@@ -194,15 +195,33 @@ -(void)drawSprite:(CCSprite *)sprite withEffect:(CCEffect *)effect uniforms:(NSM
         if (directRendering)
         {
             renderPass.transform = *transform;
+
+            GLKMatrix4 ndcToWorldMat;
+            [renderer.globalShaderUniforms[CCShaderUniformProjectionInv] getValue:&ndcToWorldMat];
+            renderPass.ndcToWorld = ndcToWorldMat;
 
             [renderPass begin:previousPassTexture];
             [renderPass update];
             [renderPass end];
         }
         else
         {
-            renderPass.transform = GLKMatrix4MakeOrtho(0.0f, _contentSize.width, 0.0f, _contentSize.height, -1024.0f, 1024.0f);
+            BOOL inverted;
+            
+            GLKMatrix4 renderTargetProjection = GLKMatrix4MakeOrtho(0.0f, _contentSize.width, 0.0f, _contentSize.height, -1024.0f, 1024.0f);
+            GLKMatrix4 invRenderTargetProjection = GLKMatrix4Invert(renderTargetProjection, &inverted);
+            NSAssert(inverted, @"Unable to invert matrix.");
+            
+            GLKMatrix4 invGlobalProjection;
+            [renderer.globalShaderUniforms[CCShaderUniformProjectionInv] getValue:&invGlobalProjection];
+            
+            GLKMatrix4 ndcToNodeMat = invRenderTargetProjection;
+            GLKMatrix4 nodeToWorldMat = GLKMatrix4Multiply(invGlobalProjection, *transform);
+            GLKMatrix4 ndcToWorldMat = GLKMatrix4Multiply(nodeToWorldMat, ndcToNodeMat);
 
+            renderPass.transform = renderTargetProjection;
+            renderPass.ndcToWorld = ndcToWorldMat;
+            
             CGSize rtSize = CGSizeMake(_contentSize.width * _contentScale, _contentSize.height * _contentScale);
             rtSize.width = (rtSize.width <= 1.0f) ? 1.0f : rtSize.width;
             rtSize.height = (rtSize.height <= 1.0f) ? 1.0f : rtSize.height;

cocos2d/CCEffect_Private.h

@@ -96,6 +96,7 @@ typedef void (^CCEffectRenderPassEndBlock)(CCEffectRenderPass *pass);
 @property (nonatomic) CCRenderer* renderer;
 @property (nonatomic) CCSpriteVertexes verts;
 @property (nonatomic) GLKMatrix4 transform;
+@property (nonatomic) GLKMatrix4 ndcToWorld;
 @property (nonatomic) CCBlendMode* blendMode;
 @property (nonatomic) CCShader* shader;
 @property (nonatomic) NSMutableDictionary* shaderUniforms;