From de0bf0d552358107a3879cc2b575e1dbccceb505 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Fri, 7 Aug 2026 06:16:30 +0200
Subject: [PATCH] Fix missing distortion rendering on Deformable materials

#4045
---
 .../Materials/DeformableMaterialShader.cpp       | 16 +++++++++++++---
 .../Materials/DeformableMaterialShader.h         |  4 ++++
 .../MaterialGenerator/MaterialGenerator.cpp      |  4 +++-
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/Source/Engine/Graphics/Materials/DeformableMaterialShader.cpp b/Source/Engine/Graphics/Materials/DeformableMaterialShader.cpp
index 6260163f4..6c7e5a20c 100644
--- a/Source/Engine/Graphics/Materials/DeformableMaterialShader.cpp
+++ b/Source/Engine/Graphics/Materials/DeformableMaterialShader.cpp
@@ -112,6 +112,7 @@ bool DeformableMaterialShader::Load()
     auto psDesc = GPUPipelineState::Description::Default;
     psDesc.DepthEnable = (_info.FeaturesFlags & MaterialFeaturesFlags::DisableDepthTest) == MaterialFeaturesFlags::None;
     psDesc.DepthWriteEnable = (_info.FeaturesFlags & MaterialFeaturesFlags::DisableDepthWrite) == MaterialFeaturesFlags::None;
+    psDesc.VS = _shader->GetVS("VS_SplineModel");
 
 #if GPU_ALLOW_TESSELLATION_SHADERS
     // Check if use tessellation (both material and runtime supports it)
@@ -127,7 +128,6 @@ bool DeformableMaterialShader::Load()
     if (_shader->HasShader("PS_QuadOverdraw"))
     {
         // Quad Overdraw
-        psDesc.VS = _shader->GetVS("VS_SplineModel");
         psDesc.PS = _shader->GetPS("PS_QuadOverdraw");
         _cache.QuadOverdraw.Init(psDesc);
     }
@@ -142,7 +142,6 @@ bool DeformableMaterialShader::Load()
         psDesc.StencilPassOp = StencilOperation::Replace;
 
         // GBuffer Pass
-        psDesc.VS = _shader->GetVS("VS_SplineModel");
         psDesc.PS = _shader->GetPS("PS_GBuffer");
         _cache.Default.Init(psDesc);
 
@@ -154,7 +153,6 @@ bool DeformableMaterialShader::Load()
         _drawModes |= DrawPass::Forward;
 
         // Forward Pass
-        psDesc.VS = _shader->GetVS("VS_SplineModel");
         psDesc.PS = _shader->GetPS("PS_Forward");
         psDesc.DepthWriteEnable = false;
         psDesc.BlendMode = BlendingMode::AlphaBlend;
@@ -171,6 +169,18 @@ bool DeformableMaterialShader::Load()
             break;
         }
         _cache.Default.Init(psDesc);
+
+        // Check if use transparent distortion pass
+        if (_shader->HasShader("PS_Distortion"))
+        {
+            _drawModes |= DrawPass::Distortion;
+
+            // Accumulate Distortion Pass
+            psDesc.PS = _shader->GetPS("PS_Distortion");
+            psDesc.BlendMode = BlendingMode::Add;
+            psDesc.DepthWriteEnable = false;
+            _cache.Distortion.Init(psDesc);
+        }
     }
 
     // Depth Pass
diff --git a/Source/Engine/Graphics/Materials/DeformableMaterialShader.h b/Source/Engine/Graphics/Materials/DeformableMaterialShader.h
index 45651c090..64c40c165 100644
--- a/Source/Engine/Graphics/Materials/DeformableMaterialShader.h
+++ b/Source/Engine/Graphics/Materials/DeformableMaterialShader.h
@@ -14,6 +14,7 @@ private:
     {
         PipelineStateCache Default;
         PipelineStateCache Depth;
+        PipelineStateCache Distortion;
 #if USE_EDITOR
         PipelineStateCache QuadOverdraw;
 #endif
@@ -29,6 +30,8 @@ private:
             case DrawPass::GlobalSurfaceAtlas:
             case DrawPass::Forward:
                 return &Default;
+            case DrawPass::Distortion:
+                return &Distortion;
 #if USE_EDITOR
             case DrawPass::QuadOverdraw:
                 return &QuadOverdraw;
@@ -42,6 +45,7 @@ private:
         {
             Default.Release();
             Depth.Release();
+            Distortion.Release();
 #if USE_EDITOR
             QuadOverdraw.Release();
 #endif
diff --git a/Source/Engine/Tools/MaterialGenerator/MaterialGenerator.cpp b/Source/Engine/Tools/MaterialGenerator/MaterialGenerator.cpp
index 685aa1040..dab832758 100644
--- a/Source/Engine/Tools/MaterialGenerator/MaterialGenerator.cpp
+++ b/Source/Engine/Tools/MaterialGenerator/MaterialGenerator.cpp
@@ -246,7 +246,9 @@ bool MaterialGenerator::Generate(WriteStream& source, MaterialInfo& materialInfo
             ADD_FEATURE(TessellationFeature);
         if (isOpaque)
             ADD_FEATURE(DeferredShadingFeature);
-        if (materialInfo.BlendMode != MaterialBlendMode::Opaque)
+        if (!isOpaque && (materialInfo.FeaturesFlags & MaterialFeaturesFlags::DisableDistortion) == MaterialFeaturesFlags::None)
+            ADD_FEATURE(DistortionFeature);
+        if (!isOpaque)
             ADD_FEATURE(ForwardShadingFeature);
         break;
     default: