CCEffectLighting - Start adding support for multiple lights

Author: Thayer J Andrews

cocos2d/CCEffectLighting.h

@@ -19,11 +19,6 @@
 /// @name Accessing Effect Attributes
 /// -----------------------------------------------------------------------
 
-/** The lights that will contribute to the lighting of the affected
- *  node.
- */
-@property (nonatomic, strong) CCLightNode *light;
-
 
 /// -----------------------------------------------------------------------
 /// @name Initializing a CCEffectLighting object
@@ -39,11 +34,11 @@
 /**
  *  Initializes a CCEffectLighting object with the supplied parameters.
  *
- *  @param environment The node that will light the affected node.
+ *  @param environment The array of lights that will light the affected node.
  *
  *  @return The CCEffectLighting object.
  */
--(id)initWithLight:(CCLightNode *)light;
+-(id)initWithLights:(NSArray *)lights;
 
 
 /// -----------------------------------------------------------------------
@@ -53,10 +48,35 @@
 /**
  *  Creates a CCEffectLighting object with the supplied parameters.
  *
- *  @param environment The node that will light the affected node.
+ *  @param environment The array of lights that will light the affected node.
  *
  *  @return The CCEffectLighting object.
  */
-+(id)effectWithLight:(CCLightNode *)light;
++(id)effectWithLights:(NSArray *)lights;
+
+
+/// -----------------------------------------------------------------------
+/// @name Adding and removing lights
+/// -----------------------------------------------------------------------
+
+/**
+ *  Adds a light to the effect.
+ *
+ *  @param light CCLightNode to add.
+ */
+-(void) addLight:(CCLightNode *)light;
+
+/**
+ *  Removes a light from the effect.
+ *
+ *  @param light The light node to remove.
+ */
+-(void) removeLight:(CCLightNode *)light;
+
+/**
+ *  Removes all lights from the effect.
+ */
+-(void) removeAllLights;
+
 
 @end

cocos2d/CCEffectLighting.m

@@ -19,17 +19,19 @@
 
 @interface CCEffectLighting ()
 
+@property (nonatomic, strong) NSMutableArray *lights;
+
 @end
 
 
 @implementation CCEffectLighting
 
 -(id)init
 {
-    return [self initWithLight:nil];
+    return [self initWithLights:nil];
 }
 
--(id)initWithLight:(CCLightNode *)light
+-(id)initWithLights:(NSArray *)lights
 {
     NSArray *fragUniforms = @[
                               [CCEffectUniform uniform:@"vec4" name:@"u_lightColor" value:[NSValue valueWithGLKVector4:GLKVector4Make(1.0f, 1.0f, 1.0f, 1.0f)]],
@@ -38,7 +40,7 @@ -(id)initWithLight:(CCLightNode *)light
 
     NSArray *vertUniforms = @[
                               [CCEffectUniform uniform:@"mat4" name:@"u_ndcToTangentSpace" value:[NSValue valueWithGLKMatrix4:GLKMatrix4Identity]],
-                              [CCEffectUniform uniform:@"vec4" name:@"u_lightPosition" value:[NSValue valueWithGLKVector2:GLKVector2Make(0.0f, 0.0f)]]
+                              [CCEffectUniform uniform:@"vec4" name:@"u_lightVector" value:[NSValue valueWithGLKVector2:GLKVector2Make(0.0f, 0.0f)]]
                               ];
 
     NSArray *varyings = @[
@@ -49,16 +51,39 @@ -(id)initWithLight:(CCLightNode *)light
     {
         self.debugName = @"CCEffectLighting";
 
-        _light = light;
+        if (lights)
+        {
+            _lights = [lights mutableCopy];
+        }
+        else
+        {
+            _lights = [[NSMutableArray alloc] init];
+        }
     }
     return self;
 }
 
-+(id)effectWithLight:(CCLightNode *)light
++(id)effectWithLight:(NSArray *)lights
+{
+    return [[self alloc] initWithLights:lights];
+}
+
+-(void)addLight:(CCLightNode *)light
 {
-    return [[self alloc] initWithLight:light];
+    [_lights addObject:light];
 }
 
+-(void)removeLight:(CCLightNode *)light
+{
+    [_lights removeObject:light];
+}
+
+-(void)removeAllLights
+{
+    [_lights removeAllObjects];
+}
+
+
 -(void)buildFragmentFunctions
 {
     self.fragmentFunctions = [[NSMutableArray alloc] init];
@@ -94,7 +119,7 @@ -(void)buildVertexFunctions
                                    // vertex. cc_Position was transformed on the CPU so we need to
                                    // back it out from NDC (normalized device coords) to tangent
                                    // space before using it to compute the light direction.
-                                   v_tangentSpaceLightDir = normalize(u_lightPosition - u_ndcToTangentSpace * cc_Position);
+                                   v_tangentSpaceLightDir = normalize(u_lightVector - u_ndcToTangentSpace * cc_Position);
                                    return cc_Position;
                                    );
 
@@ -115,21 +140,31 @@ -(void)buildRenderPasses
         pass.shaderUniforms[CCShaderUniformPreviousPassTexture] = previousPassTexture;
         pass.shaderUniforms[CCShaderUniformTexCoord1Center] = [NSValue valueWithGLKVector2:pass.texCoord1Center];
         pass.shaderUniforms[CCShaderUniformTexCoord1Extents] = [NSValue valueWithGLKVector2:pass.texCoord1Extents];
-        
-        // Get the transform from the light's coordinate space to the effect's coordinate space.
-        GLKMatrix4 lightNodeToEffectNode = weakSelf.light ? CCEffectUtilsTransformFromNodeToNode(weakSelf.light, pass.node, nil) : GLKMatrix4Identity;
-        
-        // Compute the light's position in the effect node's coordinate system.
-        GLKVector4 lightPosition = GLKMatrix4MultiplyVector4(lightNodeToEffectNode, GLKVector4Make(weakSelf.light.anchorPointInPoints.x, weakSelf.light.anchorPointInPoints.y, 500.0f, 1.0f));
-        
-        GLKVector4 lightColor = GLKVector4MultiplyScalar(weakSelf.light.color.glkVector4, weakSelf.light.intensity);
-        GLKVector4 ambientColor = GLKVector4MultiplyScalar(weakSelf.light.ambientColor.glkVector4, weakSelf.light.ambientIntensity);
-        
-        pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_lightColor"]] = [NSValue valueWithGLKVector4:lightColor];
-        pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_lightPosition"]] = [NSValue valueWithGLKVector4:lightPosition];
-        pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_globalAmbientColor"]] = [NSValue valueWithGLKVector4:ambientColor];
+
+        // Matrix for converting NDC (normalized device coordinates (aka normalized render target coordinates)
+        // to node local coordinates.
         pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_ndcToTangentSpace"]] = [NSValue valueWithGLKMatrix4:pass.ndcToNodeLocal];
-        
+
+        GLKVector4 globalAmbientColor = GLKVector4Make(0.0f, 0.0f, 0.0f, 1.0f);
+        for (CCLightNode *light in weakSelf.lights)
+        {
+            // Add this light's ambient contribution to the global ambient light color.
+            globalAmbientColor = GLKVector4Add(globalAmbientColor, GLKVector4MultiplyScalar(light.ambientColor.glkVector4, light.ambientIntensity));
+
+            // Get the transform from the light's coordinate space to the effect's coordinate space.
+            GLKMatrix4 lightNodeToEffectNode = CCEffectUtilsTransformFromNodeToNode(light, pass.node, nil);
+            
+            // Compute the light's position in the effect node's coordinate system.
+            GLKVector4 lightPosition = GLKMatrix4MultiplyVector4(lightNodeToEffectNode, GLKVector4Make(light.anchorPointInPoints.x, light.anchorPointInPoints.y, 500.0f, 1.0f));
+            
+            GLKVector4 lightColor = GLKVector4MultiplyScalar(light.color.glkVector4, light.intensity);
+            
+            pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_lightColor"]] = [NSValue valueWithGLKVector4:lightColor];
+            pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_lightVector"]] = [NSValue valueWithGLKVector4:lightPosition];
+        }
+
+        pass.shaderUniforms[weakSelf.uniformTranslationTable[@"u_globalAmbientColor"]] = [NSValue valueWithGLKVector4:globalAmbientColor];
+
     } copy]];
 
     self.renderPasses = @[pass0];