Resetting shader key scope for multi pass materials (#456)

* resetting shader key scope for multi pass materials

* upped version of asset compiler to 4

sources/engine/Xenko.Assets/Materials/MaterialAssetCompiler.cs

@@ -53,7 +53,7 @@ private class MaterialCompileCommand : AssetCommand<MaterialAsset>
             public MaterialCompileCommand(string url, AssetItem assetItem, MaterialAsset value, AssetCompilerContext context)
                 : base(url, value, assetItem.Package)
             {
-                Version = 3;
+                Version = 4;
                 this.assetItem = assetItem;
                 colorSpace = context.GetColorSpace();
                 assetUrl = new UFile(url);

sources/engine/Xenko.Rendering/Rendering/Materials/MaterialGeneratorContext.cs

@@ -142,6 +142,8 @@ public ShaderSource GetStreamFinalModifier<T>(MaterialShaderStage stage)
 
         public MaterialPass PushPass()
         {
+            ResetParameterKeys();
+
             var materialPass = new MaterialPass { PassIndex = PassIndex };
             Material.Passes.Add(materialPass);
 

sources/engine/Xenko.Rendering/Rendering/Materials/ShaderGeneratorContext.cs

@@ -170,6 +170,12 @@ public ObjectParameterKey<SamplerState> GetSamplerKey(ComputeColorParameterSampl
             return GetSamplerKey(samplerStateDesc, graphicsDevice);
         }
 
+        protected void ResetParameterKeys()
+        {
+            parameterKeyIndices.Clear();
+            declaredSamplerStates.Clear();
+        }
+
         public void PushOverrides(MaterialOverrides overrides)
         {
             if (overrides == null) throw new ArgumentNullException("overrides");