Forward pass now control its depth test. Optimization with clip and depth prepass is only for Lit/layeredLit shader

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/Unlit/BaseUnlitUI.cs

         protected MaterialProperty enableBlendModePreserveSpecularLighting = null;
         protected const string kEnableBlendModePreserveSpecularLighting = "_EnableBlendModePreserveSpecularLighting";
 
+        protected const string kZTestDepthEqualForOpaque = "_ZTestDepthEqualForOpaque";
+        protected const string kZTestModeDistortion = "_ZTestModeDistortion";
 
         // See comment in LitProperties.hlsl
         const string kEmissionColor = "_EmissionColor";
             CoreUtils.SetKeyword(material, "_BLENDMODE_ADD", false);
             CoreUtils.SetKeyword(material, "_BLENDMODE_PRE_MULTIPLY", false);
 
+            // If the material use the kZTestDepthEqualForOpaque it mean it require depth equal test for opaque but transparent are not affected
+            if (material.HasProperty(kZTestDepthEqualForOpaque))
+            {
+                if (surfaceType == SurfaceType.Opaque)
+                    material.SetInt(kZTestDepthEqualForOpaque, (int)UnityEngine.Rendering.CompareFunction.Equal);
+                else
+                    material.SetInt(kZTestDepthEqualForOpaque, (int)UnityEngine.Rendering.CompareFunction.LessEqual);
+            }
+
             if (surfaceType == SurfaceType.Opaque)
             {
                 material.SetOverrideTag("RenderType", alphaTestEnable ? "TransparentCutout" : "");
                 bool distortionDepthTest = material.GetFloat(kDistortionDepthTest) > 0.0f;
                 if (distortionDepthTest)
                 {
-                    material.SetInt("_ZTestMode", (int)UnityEngine.Rendering.CompareFunction.LessEqual);
+                    material.SetInt(kZTestModeDistortion, (int)UnityEngine.Rendering.CompareFunction.LessEqual);
-                    material.SetInt("_ZTestMode", (int)UnityEngine.Rendering.CompareFunction.Always);
+                    material.SetInt(kZTestModeDistortion, (int)UnityEngine.Rendering.CompareFunction.Always);
                 }
 
                 var distortionBlendMode = material.GetInt(kDistortionBlendMode);

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

                     m_ForwardAndForwardOnlyPassNames[1] = HDShaderPassNames.s_ForwardName;
 
                     var passNames = m_FrameSettings.enableForwardRenderingOnly ? m_ForwardAndForwardOnlyPassNames : m_ForwardOnlyPassNames;
-                    // Forward opaque material always have a prepass (whether or not we use deferred, whether or not there is option like alpha test only) so we pass the right depth state here.
-                    RenderOpaqueRenderList(cullResults, camera, renderContext, cmd, passNames, m_currentRendererConfigurationBakedLighting, null, m_DepthStateOpaqueWithPrepass);
+                    RenderOpaqueRenderList(cullResults, camera, renderContext, cmd, passNames, m_currentRendererConfigurationBakedLighting);
                 }
                 else
                 {

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/LayeredLit/LayeredLit.shader

         [HideInInspector] _DstBlend ("__dst", Float) = 0.0
         [HideInInspector] _ZWrite ("__zw", Float) = 1.0
         [HideInInspector] _CullMode("__cullmode", Float) = 2.0
-        [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
+        [HideInInspector] _ZTestDepthEqualForOpaque("_ZTestDepthEqualForOpaque", Int) = 8
 
         [ToggleUI] _EnableFogOnTransparent("Enable Fog", Float) = 1.0
         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
                 Pass Replace
             }
 
-            Blend[_SrcBlend][_DstBlend]
-            ZWrite[_ZWrite]
-            Cull[_CullMode]
+            Blend [_SrcBlend][_DstBlend]
+            // In case of forward we want to have depth equal for opaque mesh
+            ZTest [_ZTestDepthEqualForOpaque]
+            ZWrite [_ZWrite]
+            Cull [_CullMode]
 
             HLSLPROGRAM
 
             #pragma multi_compile USE_FPTL_LIGHTLIST USE_CLUSTERED_LIGHTLIST
 
             #define SHADERPASS SHADERPASS_FORWARD
+            // In case of opaque we don't want to perform the alpha test, it is done in depth prepass and we use depth equal for ztest (setup from UI)
+            #ifndef _SURFACE_TYPE_TRANSPARENT
+                #define SHADERPASS_FORWARD_BYPASS_ALPHA_TEST
+            #endif
             #include "../../ShaderVariables.hlsl"
             #ifdef DEBUG_DISPLAY
             #include "../../Debug/DebugDisplay.hlsl"

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/LayeredLit/LayeredLitTessellation.shader

         [HideInInspector] _DstBlend ("__dst", Float) = 0.0
         [HideInInspector] _ZWrite ("__zw", Float) = 1.0
         [HideInInspector] _CullMode("__cullmode", Float) = 2.0
-        [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
+        [HideInInspector] _ZTestDepthEqualForOpaque("_ZTestDepthEqualForOpaque", Int) = 8
 
         [ToggleUI] _EnableFogOnTransparent("Enable Fog", Float) = 1.0
         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
                 Pass Replace
             }
 
-            Blend[_SrcBlend][_DstBlend]
-            ZWrite[_ZWrite]
-            Cull[_CullMode]
+            Blend [_SrcBlend][_DstBlend]
+            // In case of forward we want to have depth equal for opaque mesh
+            ZTest [_ZTestDepthEqualForOpaque]
+            ZWrite [_ZWrite]
+            Cull [_CullMode]
 
             HLSLPROGRAM
 
             #pragma multi_compile USE_FPTL_LIGHTLIST USE_CLUSTERED_LIGHTLIST
 
             #define SHADERPASS SHADERPASS_FORWARD
+            // In case of opaque we don't want to perform the alpha test, it is done in depth prepass and we use depth equal for ztest (setup from UI)
+            #ifndef _SURFACE_TYPE_TRANSPARENT
+                #define SHADERPASS_FORWARD_BYPASS_ALPHA_TEST
+            #endif
             #include "../../ShaderVariables.hlsl"
             #ifdef DEBUG_DISPLAY
             #include "../../Debug/DebugDisplay.hlsl"

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.shader

         [HideInInspector] _ZWrite("__zw", Float) = 1.0
         [HideInInspector] _CullMode("__cullmode", Float) = 2.0
         [HideInInspector] _CullModeForward("__cullmodeForward", Float) = 2.0 // This mode is dedicated to Forward to correctly handle backface then front face rendering thin transparent
-        [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
+        [HideInInspector] _ZTestDepthEqualForOpaque("_ZTestDepthEqualForOpaque", Int) = 8
+        [HideInInspector] _ZTestModeDistortion("_ZTestModeDistortion", Int) = 8
 
         [ToggleUI] _EnableFogOnTransparent("Enable Fog", Float) = 1.0
         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
             #pragma multi_compile _ SHADOWS_SHADOWMASK
 
             #define SHADERPASS SHADERPASS_GBUFFER
-            #define SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST
+            #define SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST // This define allow to not perform the alpha test (alpha test is done during depth prepass)
             #include "../../ShaderVariables.hlsl"
             #ifdef DEBUG_DISPLAY
             #include "../../Debug/DebugDisplay.hlsl"
 
             Blend [_DistortionSrcBlend] [_DistortionDstBlend], [_DistortionBlurSrcBlend] [_DistortionBlurDstBlend]
             BlendOp Add, [_DistortionBlurBlendOp]
-            ZTest [_ZTestMode]
+            ZTest [_ZTestModeDistortion]
             ZWrite off
             Cull [_CullMode]
 
             }
 
             Blend [_SrcBlend] [_DstBlend]
+            // In case of forward we want to have depth equal for opaque mesh
+            ZTest [_ZTestDepthEqualForOpaque]
             ZWrite [_ZWrite]
             Cull [_CullModeForward]
 
             #pragma multi_compile USE_FPTL_LIGHTLIST USE_CLUSTERED_LIGHTLIST
 
             #define SHADERPASS SHADERPASS_FORWARD
+            // In case of opaque we don't want to perform the alpha test, it is done in depth prepass and we use depth equal for ztest (setup from UI)
+            #ifndef _SURFACE_TYPE_TRANSPARENT
+                #define SHADERPASS_FORWARD_BYPASS_ALPHA_TEST
+            #endif
             #include "../../ShaderVariables.hlsl"
             #ifdef DEBUG_DISPLAY
             #include "../../Debug/DebugDisplay.hlsl"

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/LitTessellation.shader

         [HideInInspector] _ZWrite("__zw", Float) = 1.0
         [HideInInspector] _CullMode("__cullmode", Float) = 2.0
         [HideInInspector] _CullModeForward("__cullmodeForward", Float) = 2.0 // This mode is dedicated to Forward to correctly handle backface then front face rendering thin transparent
-        [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
+        [HideInInspector] _ZTestDepthEqualForOpaque("_ZTestDepthEqualForOpaque", Int) = 8
+        [HideInInspector] _ZTestModeDistortion("_ZTestModeDistortion", Int) = 8
 
         [ToggleUI] _EnableFogOnTransparent("Enable Fog", Float) = 1.0
         [ToggleUI] _EnableBlendModePreserveSpecularLighting("Enable Blend Mode Preserve Specular Lighting", Float) = 1.0
             #pragma multi_compile _ SHADOWS_SHADOWMASK
 
             #define SHADERPASS SHADERPASS_GBUFFER
-            #define SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST
+            #define SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST // This define allow to not perform the alpha test (alpha test is done during depth prepass)
             #include "../../ShaderVariables.hlsl"
             #ifdef DEBUG_DISPLAY
             #include "../../Debug/DebugDisplay.hlsl"
 
             Blend [_DistortionSrcBlend] [_DistortionDstBlend], [_DistortionBlurSrcBlend] [_DistortionBlurDstBlend]
             BlendOp Add, [_DistortionBlurBlendOp]
-            ZTest [_ZTestMode]
+            ZTest [_ZTestModeDistortion]
             ZWrite off
             Cull [_CullMode]
 
             }
 
             Blend [_SrcBlend] [_DstBlend]
+            // In case of forward we want to have depth equal for opaque mesh
+            ZTest [_ZTestDepthEqualForOpaque]
-            Cull[_CullModeForward]
+            Cull [_CullModeForward]
 
             HLSLPROGRAM
 
             #pragma multi_compile USE_FPTL_LIGHTLIST USE_CLUSTERED_LIGHTLIST
 
             #define SHADERPASS SHADERPASS_FORWARD
+            // In case of opaque we don't want to perform the alpha test, it is done in depth prepass and we use depth equal for ztest (setup from UI)
+            #ifndef _SURFACE_TYPE_TRANSPARENT
+                #define SHADERPASS_FORWARD_BYPASS_ALPHA_TEST
+            #endif
             #include "../../ShaderVariables.hlsl"
             #ifdef DEBUG_DISPLAY
             #include "../../Debug/DebugDisplay.hlsl"

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Material.hlsl

 // Alpha test replacement
 //-----------------------------------------------------------------------------
 
-// This function must be use instead of clip instruction. It allow to manage in which case the clip is perform
+// This function must be use instead of clip instruction. It allow to manage in which case the clip is perform for optimization purpose
-    // If we have a prepass, we need to remove the clip from the GBuffer pass (otherwise HiZ does not work on PS4) - SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST
-    // For Forward (Lit or Unlit)
-    // Opaque geometry always has a depth pre-pass so we never want to do the clip here. For transparent we perform the clip as usual.
+    // If we have a prepass, we  may want to remove the clip from the GBuffer pass (otherwise HiZ does not work on PS4) - SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST
+    // For Forward Opaque:
+    // If we have a prepass, we may want to remove the clip from the forward pass (otherwise HiZ does not work on PS4) - SHADERPASS_FORWARD_BYPASS_ALPHA_TEST
+    // For Forward Transparent
-#if !(SHADERPASS == SHADERPASS_FORWARD && !defined(_SURFACE_TYPE_TRANSPARENT)) && !(SHADERPASS == SHADERPASS_FORWARD_UNLIT && !defined(_SURFACE_TYPE_TRANSPARENT)) && !defined(SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST) && !(SHADERPASS == SHADERPASS_LIGHT_TRANSPORT)
+    // Note: If SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST or SHADERPASS_FORWARD_BYPASS_ALPHA_TEST are used, it mean that we must use ZTest depth equal for the pass (Need to use _ZTestDepthEqualForOpaque property).
+#if !defined(SHADERPASS_FORWARD_BYPASS_ALPHA_TEST) && !defined(SHADERPASS_GBUFFER_BYPASS_ALPHA_TEST) && !(SHADERPASS == SHADERPASS_LIGHT_TRANSPORT)
     clip(alpha - alphaCutoff);
 #endif
 }

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Unlit/Unlit.shader

         [HideInInspector] _DstBlend("__dst", Float) = 0.0
         [HideInInspector] _ZWrite("__zw", Float) = 1.0
         [HideInInspector] _CullMode("__cullmode", Float) = 2.0
-        [HideInInspector] _ZTestMode("_ZTestMode", Int) = 8
+        [HideInInspector] _ZTestModeDistortion("_ZTestModeDistortion", Int) = 8
 
         [ToggleUI] _EnableFogOnTransparent("Enable Fog", Float) = 0.0
         [ToggleUI] _DoubleSidedEnable("Double sided enable", Float) = 0.0
 
     SubShader
     {
-        // Caution: The outline selection in the editor use the vertex shader/hull/domain shader of the first pass declare. So it should not bethe  meta pass.
+        // Caution: The outline selection in the editor use the vertex shader/hull/domain shader of the first pass declare. So it should not be the meta pass.
-        // Unlit shader always render in forward
-            Name ""
+            Name "Depth prepass"
             Tags{ "LightMode" = "DepthForwardOnly" }
 
             Cull[_CullMode]
         // Unlit shader always render in forward
         Pass
         {
-            Name "ForwardUnlit"
+            Name "Forward Unlit"
             Tags { "LightMode" = "ForwardOnly" }
 
             Blend [_SrcBlend] [_DstBlend]
 
             Blend [_DistortionSrcBlend] [_DistortionDstBlend], [_DistortionBlurSrcBlend] [_DistortionBlurDstBlend]
             BlendOp Add, [_DistortionBlurBlendOp]
-            ZTest [_ZTestMode]
+            ZTest [_ZTestModeDistortion]
             ZWrite off
             Cull [_CullMode]