CCEffectStack - Fix shader uniform management

This wasn't causing any problems yet but shader uniforms for effect stacks were not being
handled properly under all circumstances. After name mangling, the old code would construct
a uniform dictionary that was never used at render time. By render time, the effects would just
receive the default uniform dictionary from CCNode.

Author: Thayer J Andrews

cocos2d/CCEffectStack.m

@@ -179,17 +179,21 @@ - (CCEffectPrepareStatus)prepareForRendering
             }
         }
 
-        // Extract passes from the stacked effects and build a flat list of
-        // passes.
+        // Extract passes and uniforms from the stacked and stitched effects and build a flat list of
+        // both.
         NSMutableArray *passes = [[NSMutableArray alloc] init];
+        NSMutableDictionary *uniforms = [[NSMutableDictionary alloc] init];
         for (CCEffect *effect in stitchedEffects)
         {
             for (CCEffectRenderPass *pass in effect.renderPasses)
             {
                 [passes addObject:pass];
             }
+            
+            [uniforms addEntriesFromDictionary:effect.shaderUniforms];
         }
         self.renderPasses = [passes copy];
+        self.shaderUniforms = uniforms;
         _passesDirty = NO;
 
         result = CCEffectPrepareSuccess;
@@ -268,25 +272,18 @@ -(CCEffect *)stitchEffects:(NSArray*)effects startIndex:(int)startIndex
     CCEffect *lastEffect = [effects lastObject];
     stitchedEffect.stitchFlags = (firstEffect.stitchFlags & CCEffectFunctionStitchBefore) | (lastEffect.stitchFlags & CCEffectFunctionStitchAfter);
 
-    // Copy the shader for this new pass from the stitched effect.
+    // Create a new render pass object and set its shader from the stitched effect
+    // that was created above.
     CCEffectRenderPass *newPass = [[CCEffectRenderPass alloc] init];
     newPass.debugLabel = @"CCEffectStack_Stitched pass 0";
     newPass.shader = stitchedEffect.shader;
-    newPass.shaderUniforms = [[NSMutableDictionary alloc] init];
 
     NSMutableArray *beginBlocks = [[NSMutableArray alloc] init];
     NSMutableArray *endBlocks = [[NSMutableArray alloc] init];
 
     for (CCEffect *effect in effects)
     {
-        // Copy the shader uniforms from each input effect to a shared
-        // dictionary for the new pass. For example, if we stitch two effects
-        // together, one with uniforms A and B and one with uniforms C and D,
-        // we will get one dictionary with A, B, C, and D.
-        //
-        // Similarly, copy the begin and end blocks from the input passes into
-        // the new pass.
-        [newPass.shaderUniforms addEntriesFromDictionary:effect.shaderUniforms];
+        // Copy the begin and end blocks from the input passes into the new pass.
         for (CCEffectRenderPass *pass in effect.renderPasses)
         {
             [beginBlocks addObjectsFromArray:pass.beginBlocks];

cocos2d/CCEffect_Private.h

@@ -117,7 +117,7 @@ typedef void (^CCEffectRenderPassEndBlock)(CCEffectRenderPass *pass);
 @interface CCEffect ()
 
 @property (nonatomic, readonly) CCShader* shader; // Note: consider adding multiple shaders (one for reach renderpass, this will help break up logic and avoid branching in a potential uber shader).
-@property (nonatomic, readonly) NSMutableDictionary* shaderUniforms;
+@property (nonatomic, strong) NSMutableDictionary* shaderUniforms;
 @property (nonatomic, readonly) NSUInteger renderPassesRequired;
 @property (nonatomic, readonly) BOOL supportsDirectRendering;
 @property (nonatomic, readonly) BOOL readyForRendering;