Add LOD Preview debug view mode

Source/Engine/Graphics/Enums.h

@@ -813,6 +813,11 @@ API_ENUM() enum class ViewMode
     /// Draw physics colliders debug view
     /// </summary>
     PhysicsColliders = 20,
+
+    /// <summary>
+    /// Draw Level Of Detail number as colors to debug LOD switches.
+    /// </summary>
+    LODPreview = 21,
 };
 
 /// <summary>

Source/Engine/Renderer/Editor/LODPreview.cpp

@@ -0,0 +1,127 @@
+// Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.
+
+#if USE_EDITOR
+
+#include "LODPreview.h"
+#include "Engine/Content/Content.h"
+#include "Engine/Content/Assets/Model.h"
+#include "Engine/Graphics/GPUDevice.h"
+#include "Engine/Graphics/GPUPipelineState.h"
+#include "Engine/Graphics/Shaders/GPUShader.h"
+#include "Engine/Graphics/Shaders/GPUConstantBuffer.h"
+#include "Engine/Graphics/RenderTask.h"
+#include "Engine/Renderer/DrawCall.h"
+
+PACK_STRUCT(struct LODPreviewMaterialShaderData {
+    Matrix ViewProjectionMatrix;
+    Matrix WorldMatrix;
+    Color Color;
+    Vector3 WorldInvScale;
+    float LODDitherFactor;
+    });
+
+LODPreviewMaterialShader::LODPreviewMaterialShader()
+{
+    _ps = GPUDevice::Instance->CreatePipelineState();
+    _shader = Content::LoadAsyncInternal<Shader>(TEXT("Shaders/Editor/LODPreview"));
+    if (!_shader)
+        return;
+#if COMPILE_WITH_DEV_ENV
+    _shader.Get()->OnReloading.Bind<LODPreviewMaterialShader, &LODPreviewMaterialShader::OnShaderReloading>(this);
+#endif
+}
+
+#if COMPILE_WITH_DEV_ENV
+
+void LODPreviewMaterialShader::OnShaderReloading(Asset* obj)
+{
+    _ps->ReleaseGPU();
+}
+
+#endif
+
+const MaterialInfo& LODPreviewMaterialShader::GetInfo() const
+{
+    return _info;
+}
+
+bool LODPreviewMaterialShader::IsReady() const
+{
+    return _shader && _shader->IsLoaded();
+}
+
+DrawPass LODPreviewMaterialShader::GetDrawModes() const
+{
+    return DrawPass::GBuffer;
+}
+
+void LODPreviewMaterialShader::Bind(BindParameters& params)
+{
+    auto context = params.GPUContext;
+    auto& drawCall = *params.FirstDrawCall;
+    auto shader = _shader->GetShader();
+    auto cb = shader->GetCB(0);
+    if (!_ps->IsValid())
+    {
+        auto psDesc = GPUPipelineState::Description::Default;
+        psDesc.VS = shader->GetVS("VS");
+        psDesc.PS = shader->GetPS("PS");
+        _ps->Init(psDesc);
+    }
+
+    // Find the LOD that produced this draw call
+    int32 lodIndex = 0;
+    for (auto& e : Content::GetAssetsRaw())
+    {
+        auto model = ScriptingObject::Cast<Model>(e.Value);
+        if (!model)
+            continue;
+        bool found = false;
+        for (const auto& lod : model->LODs)
+        {
+            for (const auto& mesh : lod.Meshes)
+            {
+                if (mesh.GetIndexBuffer() == drawCall.Geometry.IndexBuffer)
+                {
+                    lodIndex = mesh.GetLODIndex();
+                    found = true;
+                    break;
+                }
+            }
+        }
+        if (found)
+            break;
+    }
+
+    // Bind
+    if (cb && cb->GetSize())
+    {
+        ASSERT(cb->GetSize() == sizeof(LODPreviewMaterialShaderData));
+        LODPreviewMaterialShaderData data;
+        Matrix::Transpose(params.RenderContext.View.Frustum.GetMatrix(), data.ViewProjectionMatrix);
+        Matrix::Transpose(drawCall.World, data.WorldMatrix);
+        const float scaleX = Vector3(drawCall.World.M11, drawCall.World.M12, drawCall.World.M13).Length();
+        const float scaleY = Vector3(drawCall.World.M21, drawCall.World.M22, drawCall.World.M23).Length();
+        const float scaleZ = Vector3(drawCall.World.M31, drawCall.World.M32, drawCall.World.M33).Length();
+        data.WorldInvScale = Vector3(
+            scaleX > 0.00001f ? 1.0f / scaleX : 0.0f,
+            scaleY > 0.00001f ? 1.0f / scaleY : 0.0f,
+            scaleZ > 0.00001f ? 1.0f / scaleZ : 0.0f);
+        const Color colors[MODEL_MAX_LODS] = {
+            Color::White,
+            Color::Red,
+            Color::Orange,
+            Color::Yellow,
+            Color::Green,
+            Color::Blue,
+        };
+        ASSERT(lodIndex < MODEL_MAX_LODS);
+        data.Color = colors[lodIndex];
+        data.LODDitherFactor = drawCall.Surface.LODDitherFactor;
+        context->UpdateCB(cb, &data);
+        context->BindCB(0, cb);
+    }
+    context->SetState(_ps);
+}
+
+#endif

Source/Engine/Renderer/Editor/LODPreview.h

@@ -0,0 +1,47 @@
+// Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if USE_EDITOR
+
+#include "Engine/Content/AssetReference.h"
+#include "Engine/Content/Assets/Shader.h"
+#include "Engine/Content/Assets/Texture.h"
+#include "Engine/Graphics/Materials/IMaterial.h"
+
+class GPUPipelineState;
+
+/// <summary>
+/// Rendering Level Of Detail number as colors to debug LOD switches in editor.
+/// </summary>
+class LODPreviewMaterialShader : public IMaterial
+{
+private:
+
+    AssetReference<Shader> _shader;
+    GPUPipelineState* _ps = nullptr;
+    MaterialInfo _info;
+
+public:
+
+    LODPreviewMaterialShader();
+    virtual ~LODPreviewMaterialShader()
+    {
+    }
+
+private:
+
+#if COMPILE_WITH_DEV_ENV
+    void OnShaderReloading(Asset* obj);
+#endif
+
+public:
+
+    // [IMaterial]
+    const MaterialInfo& GetInfo() const override;
+    bool IsReady() const override;
+    DrawPass GetDrawModes() const override;
+    void Bind(BindParameters& params) override;
+};
+
+#endif

Source/Engine/Renderer/GBufferPass.cpp

@@ -2,8 +2,11 @@
 
 #include "GBufferPass.h"
 #include "RenderList.h"
+#if USE_EDITOR
 #include "Engine/Renderer/Editor/VertexColors.h"
 #include "Engine/Renderer/Editor/LightmapUVsDensity.h"
+#include "Engine/Renderer/Editor/LODPreview.h"
+#endif
 #include "Engine/Core/Collections/Sorting.h"
 #include "Engine/Graphics/GPUDevice.h"
 #include "Engine/Graphics/GPUContext.h"
@@ -87,11 +90,37 @@ void GBufferPass::Dispose()
     _skyModel = nullptr;
     _boxModel = nullptr;
 #if USE_EDITOR
-    SAFE_DELETE(_lightmapUVsDensityMaterialShader);
-    SAFE_DELETE(_vertexColorsMaterialShader);
+    SAFE_DELETE(_lightmapUVsDensity);
+    SAFE_DELETE(_vertexColors);
+    SAFE_DELETE(_lodPreview);
 #endif
 }
 
+#if USE_EDITOR
+
+void DebugOverrideDrawCallsMaterial(RenderContext& renderContext, IMaterial* material)
+{
+    if (material->IsReady())
+    {
+        auto& drawCallsList = renderContext.List->DrawCallsLists[(int32)DrawCallsListType::GBuffer];
+        for (int32 i : drawCallsList.Indices)
+        {
+            auto& drawCall = renderContext.List->DrawCalls[i];
+            if (drawCall.Material->IsSurface())
+            {
+                drawCall.Material = material;
+            }
+        }
+        IMaterial::InstancingHandler handler;
+        if (!material->CanUseInstancing(handler))
+        {
+            drawCallsList.CanUseInstancing = false;
+        }
+    }
+}
+
+#endif
+
 void GBufferPass::Fill(RenderContext& renderContext, GPUTextureView* lightBuffer)
 {
     PROFILE_GPU_CPU("GBuffer");
@@ -133,47 +162,21 @@ void GBufferPass::Fill(RenderContext& renderContext, GPUTextureView* lightBuffer
     // Override draw calls material to use material debug shader
     if (renderContext.View.Mode == ViewMode::LightmapUVsDensity)
     {
-        if (!_lightmapUVsDensityMaterialShader)
-            _lightmapUVsDensityMaterialShader = New<LightmapUVsDensityMaterialShader>();
-        if (_lightmapUVsDensityMaterialShader->IsReady())
-        {
-            auto& drawCallsList = renderContext.List->DrawCallsLists[(int32)DrawCallsListType::GBuffer];
-            for (int32 i : drawCallsList.Indices)
-            {
-                auto& drawCall = renderContext.List->DrawCalls[i];
-                if (drawCall.Material->IsSurface())
-                {
-                    drawCall.Material = _lightmapUVsDensityMaterialShader;
-                }
-            }
-            IMaterial::InstancingHandler handler;
-            if (!_lightmapUVsDensityMaterialShader->CanUseInstancing(handler))
-            {
-                drawCallsList.CanUseInstancing = false;
-            }
-        }
+        if (!_lightmapUVsDensity)
+            _lightmapUVsDensity = New<LightmapUVsDensityMaterialShader>();
+        DebugOverrideDrawCallsMaterial(renderContext, _lightmapUVsDensity);
     }
     else if (renderContext.View.Mode == ViewMode::VertexColors)
     {
-        if (!_vertexColorsMaterialShader)
-            _vertexColorsMaterialShader = New<VertexColorsMaterialShader>();
-        if (_vertexColorsMaterialShader->IsReady())
-        {
-            auto& drawCallsList = renderContext.List->DrawCallsLists[(int32)DrawCallsListType::GBuffer];
-            for (int32 i : drawCallsList.Indices)
-            {
-                auto& drawCall = renderContext.List->DrawCalls[i];
-                if (drawCall.Material->IsSurface())
-                {
-                    drawCall.Material = _vertexColorsMaterialShader;
-                }
-            }
-            IMaterial::InstancingHandler handler;
-            if (!_vertexColorsMaterialShader->CanUseInstancing(handler))
-            {
-                drawCallsList.CanUseInstancing = false;
-            }
-        }
+        if (!_vertexColors)
+            _vertexColors = New<VertexColorsMaterialShader>();
+        DebugOverrideDrawCallsMaterial(renderContext, _vertexColors);
+    }
+    else if (renderContext.View.Mode == ViewMode::LODPreview)
+    {
+        if (!_lodPreview)
+            _lodPreview = New<LODPreviewMaterialShader>();
+        DebugOverrideDrawCallsMaterial(renderContext, _lodPreview);
     }
     if (renderContext.View.Mode == ViewMode::PhysicsColliders)
     {

Source/Engine/Renderer/GBufferPass.h

@@ -16,8 +16,9 @@ private:
     AssetReference<Model> _skyModel;
     AssetReference<Model> _boxModel;
 #if USE_EDITOR
-    class LightmapUVsDensityMaterialShader* _lightmapUVsDensityMaterialShader = nullptr;
-    class VertexColorsMaterialShader* _vertexColorsMaterialShader = nullptr;
+    class LightmapUVsDensityMaterialShader* _lightmapUVsDensity = nullptr;
+    class VertexColorsMaterialShader* _vertexColors = nullptr;
+    class LODPreviewMaterialShader* _lodPreview = nullptr;
 #endif
 
 public: