Giving [CCTexture +none] an actual texture and sampler to make the validation happy.

Author: slembcke

cocos2d/CCTexture.m

@@ -186,6 +186,18 @@ +(void)initialize
 	CCTextureNone->_name = 0;
 	CCTextureNone->_format = CCTexturePixelFormat_RGBA8888;
 	CCTextureNone->_contentScale = 1.0;
+	
+#if __CC_METAL_SUPPORTED_AND_ENABLED
+	if([CCConfiguration sharedConfiguration].graphicsAPI == CCGraphicsAPIMetal){
+		CCMetalContext *context = [CCMetalContext currentContext];
+		NSAssert(context, @"Metal context is nil.");
+		
+		CCTextureNone->_metalSampler = [context.device newSamplerStateWithDescriptor:[MTLSamplerDescriptor new]];
+		
+		MTLTextureDescriptor *textureDesc = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm width:1 height:1 mipmapped:NO];
+		CCTextureNone->_metalTexture = [context.device newTextureWithDescriptor:textureDesc];
+	}
+#endif
 }
 
 +(instancetype)none

cocos2d/Platforms/iOS/CCMetalSupport.m

@@ -238,7 +238,7 @@ -(void)prepare
 
 		CCTexture *texture = _shaderUniforms[CCShaderUniformMainTexture] ?: [CCTexture none];
 		_textureRange = NSMakeRange(0, 1);
-		_samplers[0] = texture.metalSampler ?: [context.device newSamplerStateWithDescriptor:[MTLSamplerDescriptor new]];
+		_samplers[0] = texture.metalSampler;
 		_textures[0] = texture.metalTexture;
 	}
 }