Add WorldPosition to postfx material scene textures for world-space position sampling at uv

Content/Editor/MaterialTemplates/PostProcess.shader

@@ -18,6 +18,7 @@ float TimeParam;
 float4 ViewInfo;
 float4 ScreenSize;
 float4 TemporalAAJitter;
+float4x4 InverseViewProjectionMatrix;
 @1META_CB_END
 
 // Shader resources
@@ -62,6 +63,14 @@ MaterialInput GetMaterialInput(PixelInput input)
 	return result;
 }
 
+// Gets world space position at given pixel coordinate with given device depth
+float3 GetWorldPos(float2 uv, float deviceDepth)
+{
+	float4 clipPos = float4(uv * float2(2.0, -2.0) + float2(-1.0, 1.0), deviceDepth, 1.0);
+	float4 wsPos = mul(clipPos, InverseViewProjectionMatrix);
+	return wsPos.xyz / wsPos.w;
+}
+
 // Transforms a vector from tangent space to world space
 float3 TransformTangentVectorToWorld(MaterialInput input, float3 tangentVector)
 {

Source/Engine/Graphics/Materials/MaterialInfo.h

@@ -435,6 +435,11 @@ API_ENUM() enum class MaterialSceneTextures
     /// The material shading mode.
     /// </summary>
     ShadingModel = 10,
+
+    /// <summary>
+    /// The scene world-space position (relative to the render view origin).
+    /// </summary>
+    WorldPosition = 11,
 };
 
 /// <summary>

Source/Engine/Graphics/Materials/MaterialParams.cpp

@@ -439,6 +439,7 @@ void MaterialParameter::Bind(BindMeta& meta) const
             switch (type)
             {
             case MaterialSceneTextures::SceneDepth:
+            case MaterialSceneTextures::WorldPosition:
                 view = meta.CanSampleDepth
                            ? meta.Buffers->DepthBuffer->GetDescription().Flags & GPUTextureFlags::ReadOnlyDepthView
                                  ? meta.Buffers->DepthBuffer->ViewReadOnlyDepth()

Source/Engine/Graphics/Materials/MaterialShader.h

@@ -10,7 +10,7 @@
 /// <summary>
 /// Current materials shader version.
 /// </summary>
-#define MATERIAL_GRAPH_VERSION 156
+#define MATERIAL_GRAPH_VERSION 157
 
 class Material;
 class GPUShader;

Source/Engine/Graphics/Materials/PostFxMaterialShader.cpp

@@ -18,6 +18,7 @@ PACK_STRUCT(struct PostFxMaterialShaderData {
     Float4 ViewInfo;
     Float4 ScreenSize;
     Float4 TemporalAAJitter;
+    Matrix InverseViewProjectionMatrix;
     });
 
 void PostFxMaterialShader::Bind(BindParameters& params)
@@ -44,6 +45,7 @@ void PostFxMaterialShader::Bind(BindParameters& params)
     // Setup material constants
     {
         Matrix::Transpose(view.View, materialData->ViewMatrix);
+        Matrix::Transpose(view.IVP, materialData->InverseViewProjectionMatrix);
         materialData->ViewPos = view.Position;
         materialData->ViewFar = view.Far;
         materialData->ViewDir = view.Direction;

Source/Engine/Particles/Graph/GPU/ParticleEmitterGraph.GPU.Textures.cpp

@@ -245,6 +245,9 @@ void ParticleEmitterGPUGenerator::ProcessGroupTextures(Box* box, Node* node, Val
             value = writeLocal(VariantType::Int, String::Format(TEXT("(int)({0}.a * 3.999)"), gBuffer1Sample.Value), node);
             break;
         }
+        case MaterialSceneTextures::WorldPosition:
+            value = Value::Zero; // Not implemented
+            break;
         default:
         {
             // Sample single texture

Source/Engine/Tools/MaterialGenerator/MaterialGenerator.Textures.cpp

@@ -416,6 +416,23 @@ void MaterialGenerator::ProcessGroupTextures(Box* box, Node* node, Value& value)
             value = writeLocal(VariantType::Int, String::Format(TEXT("(int)({0}.a * 3.999)"), gBuffer1Sample->Value), node);
             break;
         }
+        case MaterialSceneTextures::WorldPosition:
+        {
+            auto depthParam = findOrAddSceneTexture(MaterialSceneTextures::SceneDepth);
+            auto depthSample = sampleTextureRaw(node, value, box, &depthParam);
+            if (depthSample == nullptr)
+                break;
+            const auto parent = box->GetParent<ShaderGraphNode<>>();
+            MaterialGraphBox* uvBox = parent->GetBox(0);
+            bool useCustomUVs = uvBox->HasConnection();
+            String uv;
+            if (useCustomUVs)
+                uv = MaterialValue::Cast(tryGetValue(uvBox, getUVs), VariantType::Float2).Value;
+            else
+                uv = TEXT("input.TexCoord.xy");
+            value = writeLocal(VariantType::Float3, String::Format(TEXT("GetWorldPos({1}, {0}.rgb)"), depthSample->Value, uv), node);
+            break;
+        }
         default:
         {
             // Sample single texture