2021.2/universal/case 1379188 particle unlit blend (#6840)

* Remove duplica alpha multiplies.

* Fix alpha modulate.

* Update changelog.

* Remove autogenerated text in changelog.

Author: eh-unity

com.unity.render-pipelines.universal/CHANGELOG.md

@@ -9,8 +9,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Changed
 - Re-added the menu button to be able to convert selected materials.
 
-
 ### Fixed
+- Fixed incorrect blending of ParticleUnlit. [case 1373188](https://issuetracker.unity3d.com/product/unity/issues/guid/1373188/)
 - Fixed max light count cpu/gpu mismatch in Editor with Android target. [case 1392965](https://issuetracker.unity3d.com/product/unity/issues/guid/1392965/)
 
 ## [12.1.4] - 2021-12-07

com.unity.render-pipelines.universal/Editor/ShaderGUI/BaseShaderGUI.cs

@@ -600,14 +600,16 @@ internal static void SetupMaterialBlendModeInternal(Material material, out int a
                 {
                     BlendMode blendMode = (BlendMode)material.GetFloat(Property.BlendMode);
 
+                    material.DisableKeyword(ShaderKeywordStrings._ALPHAPREMULTIPLY_ON);
+                    material.DisableKeyword(ShaderKeywordStrings._ALPHAMODULATE_ON);
+
                     // Specific Transparent Mode Settings
                     switch (blendMode)
                     {
                         case BlendMode.Alpha:
                             SetMaterialSrcDstBlendProperties(material,
                                 UnityEngine.Rendering.BlendMode.SrcAlpha,
                                 UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
-                            material.DisableKeyword(ShaderKeywordStrings._ALPHAPREMULTIPLY_ON);
                             break;
                         case BlendMode.Premultiply:
                             SetMaterialSrcDstBlendProperties(material,
@@ -619,13 +621,11 @@ internal static void SetupMaterialBlendModeInternal(Material material, out int a
                             SetMaterialSrcDstBlendProperties(material,
                                 UnityEngine.Rendering.BlendMode.SrcAlpha,
                                 UnityEngine.Rendering.BlendMode.One);
-                            material.DisableKeyword(ShaderKeywordStrings._ALPHAPREMULTIPLY_ON);
                             break;
                         case BlendMode.Multiply:
                             SetMaterialSrcDstBlendProperties(material,
                                 UnityEngine.Rendering.BlendMode.DstColor,
                                 UnityEngine.Rendering.BlendMode.Zero);
-                            material.DisableKeyword(ShaderKeywordStrings._ALPHAPREMULTIPLY_ON);
                             material.EnableKeyword(ShaderKeywordStrings._ALPHAMODULATE_ON);
                             break;
                     }

com.unity.render-pipelines.universal/ShaderLibrary/Unlit.hlsl

@@ -10,10 +10,6 @@ half4 UniversalFragmentUnlit(InputData inputData, SurfaceData surfaceData)
 {
     half3 albedo = surfaceData.albedo;
 
-    #if defined(_ALPHAPREMULTIPLY_ON)
-    albedo *= surfaceData.alpha;
-    #endif
-
     #if defined(DEBUG_DISPLAY)
     half4 debugColor;
 

com.unity.render-pipelines.universal/Shaders/Particles/ParticlesUnlitForwardPass.hlsl

@@ -55,15 +55,13 @@ void InitializeSurfaceData(ParticleParams particleParams, out SurfaceData surfac
     const half3 emission = 0;
     #endif
 
-    surfaceData.albedo = albedo.rgb;
+    surfaceData.albedo = albedo.rgb; // NOTE: Pre-multiplied and modulated in SampleAlbedo().
     surfaceData.specular = 0;
     surfaceData.normalTS = normalTS;
     surfaceData.emission = emission;
     surfaceData.metallic = 0;
     surfaceData.smoothness = 1;
     surfaceData.occlusion = 1;
-
-    surfaceData.albedo = AlphaModulate(surfaceData.albedo, albedo.a);
     surfaceData.alpha = albedo.a;
 
     surfaceData.clearCoatMask       = 0;

com.unity.render-pipelines.universal/Shaders/UnlitForwardPass.hlsl

@@ -101,6 +101,10 @@ half4 UnlitPassFragment(Varyings input) : SV_Target
 
     AlphaDiscard(alpha, _Cutoff);
 
+    #if defined(_ALPHAPREMULTIPLY_ON)
+    color *= alpha;
+    #endif
+
     InputData inputData;
     InitializeInputData(input, inputData);
     SETUP_DEBUG_TEXTURE_DATA(inputData, input.uv, _BaseMap);