Fix depth bounds in reversed Z

#2684

Source/Engine/Graphics/GPUContext.h

@@ -15,9 +15,13 @@
 #endif
 
 #if FLAX_REVERSE_Z
-#define GPU_DEPTH_CLEAR_VALUE 0.0f
+#define GPU_DEPTH_MIN_VALUE 1.0f
+#define GPU_DEPTH_MAX_VALUE 0.0f
+#define GPU_DEPTH_BOUNDS_SWAP(min, max) max, min
 #else
-#define GPU_DEPTH_CLEAR_VALUE 1.0f
+#define GPU_DEPTH_MIN_VALUE 0.0f
+#define GPU_DEPTH_MAX_VALUE 1.0f
+#define GPU_DEPTH_BOUNDS_SWAP(min, max) min, max
 #endif
 
 class GPUConstantBuffer;
@@ -214,7 +218,7 @@ public:
     /// <param name="depthBuffer">The depth buffer to clear.</param>
     /// <param name="depthValue">The clear depth value.</param>
     /// <param name="stencilValue">The clear stencil value.</param>
-    API_FUNCTION() virtual void ClearDepth(GPUTextureView* depthBuffer, float depthValue = GPU_DEPTH_CLEAR_VALUE, uint8 stencilValue = 0) = 0;
+    API_FUNCTION() virtual void ClearDepth(GPUTextureView* depthBuffer, float depthValue = GPU_DEPTH_MAX_VALUE, uint8 stencilValue = 0) = 0;
 
     /// <summary>
     /// Clears an unordered access buffer with a float value.
@@ -634,9 +638,10 @@ public:
     /// <summary>
     /// Sets the minimum and maximum depth values for depth bounds test.
     /// </summary>
+    /// <remarks>Both values must be between 0.0 and 1.0, MinDepth must be less than or equal to MaxDepth.</remarks>
     /// <param name="minDepth">The minimum value for depth bound test.</param>
     /// <param name="maxDepth">The maximum value for depth bound test.</param>
-    API_FUNCTION() virtual void SetDepthBounds(float minDepth, float maxDepth) = 0;
+    API_FUNCTION() virtual void SetDepthBounds(float minDepth = 0.0f, float maxDepth = 1.0f) = 0;
 
 public:
     /// <summary>

Source/Engine/Graphics/RenderTools.cpp

@@ -684,6 +684,20 @@ float RenderTools::TemporalHalton(int32 index, int32 base)
 
 Float2 RenderTools::GetDepthBounds(const RenderView& view, const Float3& nearPoint, const Float3& farPoint)
 {
+#if FLAX_REVERSE_Z
+    Float3 viewNearPoint = Float3::Transform(nearPoint, view.View);
+    Float3 viewFarPoint = Float3::Transform(farPoint, view.View);
+
+    viewNearPoint.Z = Math::Max(viewNearPoint.Z, view.Near);
+    viewFarPoint.Z = Math::Min(viewFarPoint.Z, view.Far);
+
+    Float4 clipNearPoint = Matrix::TransformPosition(view.Projection, Float4(0, 0, viewNearPoint.Z, 1));
+    Float4 clipFarPoint = Matrix::TransformPosition(view.Projection, Float4(0, 0, viewFarPoint.Z, 1));
+    clipNearPoint /= clipNearPoint.W;
+    clipFarPoint /= clipFarPoint.W;
+
+    return Float2(clipNearPoint.Z, clipFarPoint.Z);
+#else
     // Point closest the view
     const Float4 nearPointClip = Matrix::TransformPosition(view.ViewProjection(), Float4(nearPoint, 1.0));
     float nearDepth = nearPointClip.Z / nearPointClip.W;
@@ -700,8 +714,8 @@ Float2 RenderTools::GetDepthBounds(const RenderView& view, const Float3& nearPoi
     nearDepth = Math::Clamp(nearDepth, 0.0f, 1.0f);
     farDepth = Math::Clamp(farDepth, nearDepth, 1.0f);
 
-    // TODO: swap depths when using reversed depth buffer
     return Float2(nearDepth, farDepth);
+#endif
 }
 
 Float2 RenderTools::GetDepthBounds(const RenderView& view, const BoundingSphere& bounds)
@@ -713,6 +727,24 @@ Float2 RenderTools::GetDepthBounds(const RenderView& view, const BoundingSphere&
 
 Float2 RenderTools::GetDepthBounds(const RenderView& view, const Span<Float3>& points)
 {
+#if FLAX_REVERSE_Z
+    // Find min and max view depth range for list of points
+    float nearDepth = view.Far, farDepth = view.Near;
+    for (int32 i = 0; i < points.Length(); i++)
+    {
+        const Float3 viewPoint = Float3::Transform(points[i], view.View);
+        nearDepth = Math::Min(nearDepth, viewPoint.Z);
+        farDepth = Math::Max(farDepth, viewPoint.Z);
+    }
+
+    // Project end points to clip space
+    Float4 clipNearPoint = Matrix::TransformPosition(view.Projection, Float4(0, 0, nearDepth, 1));
+    Float4 clipFarPoint = Matrix::TransformPosition(view.Projection, Float4(0, 0, farDepth, 1));
+    clipNearPoint /= clipNearPoint.W;
+    clipFarPoint /= clipFarPoint.W;
+
+    return Float2(clipNearPoint.Z, clipFarPoint.Z);
+#else
     // Find min and max depth range for list of points
     float nearDepth = 1.0f, farDepth = 0.0f;
     for (int32 i = 0; i < points.Length(); i++)
@@ -729,8 +761,8 @@ Float2 RenderTools::GetDepthBounds(const RenderView& view, const Span<Float3>& p
     nearDepth = Math::Clamp(nearDepth, 0.0f, 1.0f);
     farDepth = Math::Clamp(farDepth, nearDepth, 1.0f);
 
-    // TODO: swap depths when using reversed depth buffer
     return Float2(nearDepth, farDepth);
+#endif
 }
 
 Float2 RenderTools::GetDepthBounds(const RenderView& view, const BoundingBox& bounds)
@@ -749,11 +781,21 @@ Float2 RenderTools::GetDepthBounds(const RenderView& view, const OrientedBoundin
 
 float RenderTools::GetDepthBounds(const RenderView& view, const Float3& point, bool near)
 {
+#if FLAX_REVERSE_Z
+    Float3 viewPoint = Float3::Transform(point, view.View);
+    viewPoint.Z = Math::Clamp(viewPoint.Z, view.Near, view.Far);
+
+    Float4 clipPoint = Matrix::TransformPosition(view.Projection, Float4(0, 0, viewPoint.Z, 1));
+    clipPoint /= clipPoint.W;
+
+    return clipPoint.Z;
+#else
     const Float4 pointClip = Matrix::TransformPosition(view.ViewProjection(), Float4(point, 1.0));
     float depth = pointClip.Z / pointClip.W;
     if (depth >= 1.0f)
         depth = near ? 0.0f : 1.0f; // Point is behind the view
     return Math::Clamp(depth, 0.0f, 1.0f);
+#endif
 }
 
 float RenderTools::GetDepthBounds(const RenderView& view, float viewDistance, bool near)

Source/Engine/Graphics/RenderTools.h

@@ -173,7 +173,12 @@ public:
     static Float2 GetDepthBounds(const RenderView& view, const OrientedBoundingBox& bounds);
     static float GetDepthBounds(const RenderView& view, const Float3& point, bool near);
     static float GetDepthBounds(const RenderView& view, float viewDistance, bool near);
-    static constexpr float DepthBoundMaxBackground = 1.0f - 0.0000001f; // Skip background/sky pixels from shading
+    // Skip background/sky pixels from shading
+#if FLAX_REVERSE_Z
+    static constexpr float DepthBoundMaxBackground = 0.0000001f;
+#else
+    static constexpr float DepthBoundMaxBackground = 1.0f - 0.0000001f;
+#endif
 
     // Calculates error for a given render target format to reduce floating-point precision artifacts via QuantizeColor (from Noise.hlsl).
     static Float3 GetColorQuantizationError(PixelFormat format);

Source/Engine/GraphicsDevice/Vulkan/GPUContextVulkan.cpp

@@ -796,9 +796,8 @@ void GPUContextVulkan::OnDrawCall()
     if (_psDirtyFlag && pipelineState && (_rtDepth || _rtCount))
     {
         _psDirtyFlag = false;
-        const auto cmdBuffer = _cmdBufferManager->GetCmdBuffer()->GetHandle();
         const auto pipeline = pipelineState->GetState(_renderPass, _vertexLayout);
-        vkCmdBindPipeline(cmdBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
+        vkCmdBindPipeline(cmdBuffer->GetHandle(), VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
         RENDER_STAT_PS_STATE_CHANGE();
         if (_depthBoundsEnable && (!_currentState || !_currentState->DepthBoundsEnable))
         {

Source/Engine/Renderer/AmbientOcclusionPass.cpp

@@ -536,7 +536,7 @@ void AmbientOcclusionPass::Render(RenderContext& renderContext)
     }
 
     // Apply
-    context->SetDepthBounds(0.0f, RenderTools::GetDepthBounds(renderContext.View, aoSettings.FadeOutDistance, false));
+    context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(GPU_DEPTH_MIN_VALUE, RenderTools::GetDepthBounds(renderContext.View, aoSettings.FadeOutDistance, false)));
     context->BindSR(SSAO_TEXTURE_SLOT0, m_finalResults->ViewArray());
     context->SetViewportAndScissors((float)m_sizeX, (float)m_sizeY);
     context->SetState(settings.SkipHalfPixels ? _psApplyHalf : _psApply);

Source/Engine/Renderer/LightPass.cpp

@@ -283,7 +283,7 @@ void LightPass::RenderLights(RenderContextBatch& renderContextBatch, GPUTextureV
         if (_depthBounds)
         {
             Float2 minMaxDepth = RenderTools::GetDepthBounds(view, BoundingSphere(light.Position, light.Radius));
-            context->SetDepthBounds(minMaxDepth.X, minMaxDepth.Y);
+            context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(minMaxDepth.X, minMaxDepth.Y));
         }
         context->UpdateCB(cb0, &perLight);
         context->BindCB(0, cb0);
@@ -331,7 +331,7 @@ void LightPass::RenderLights(RenderContextBatch& renderContextBatch, GPUTextureV
         if (_depthBounds)
         {
             Float2 minMaxDepth = RenderTools::GetDepthBounds(view, BoundingSphere(light.Position, light.Radius));
-            context->SetDepthBounds(minMaxDepth.X, minMaxDepth.Y);
+            context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(minMaxDepth.X, minMaxDepth.Y));
         }
         context->UpdateCB(cb0, &perLight);
         context->BindCB(0, cb0);
@@ -365,7 +365,7 @@ void LightPass::RenderLights(RenderContextBatch& renderContextBatch, GPUTextureV
 
         // Calculate lighting
         if (_depthBounds)
-            context->SetDepthBounds(0.0f, RenderTools::DepthBoundMaxBackground);
+            context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(GPU_DEPTH_MIN_VALUE, RenderTools::DepthBoundMaxBackground));
         context->UpdateCB(cb0, &perLight);
         context->BindCB(0, cb0);
         context->BindCB(1, cb1);
@@ -398,7 +398,7 @@ void LightPass::RenderLights(RenderContextBatch& renderContextBatch, GPUTextureV
         if (_depthBounds)
         {
             Float2 minMaxDepth = RenderTools::GetDepthBounds(view, BoundingSphere(light.Position, light.Radius));
-            context->SetDepthBounds(minMaxDepth.X, minMaxDepth.Y);
+            context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(minMaxDepth.X, minMaxDepth.Y));
         }
         context->UpdateCB(cb0, &perLight);
         context->BindCB(0, cb0);
@@ -411,7 +411,7 @@ void LightPass::RenderLights(RenderContextBatch& renderContextBatch, GPUTextureV
 
     // Restore state
     if (_depthBounds)
-        context->SetDepthBounds(0, 1);
+        context->SetDepthBounds();
     context->ResetRenderTarget();
     context->ResetSR();
     context->ResetCB();

Source/Engine/Renderer/ReflectionsPass.cpp

@@ -347,7 +347,7 @@ void ReflectionsPass::Render(RenderContext& renderContext, GPUTextureView* light
 
             // Setup depth bounds (if device supports it)
             if (_depthBounds)
-                context->SetDepthBounds(minMaxDepth.X, minMaxDepth.Y);
+                context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(minMaxDepth.X, minMaxDepth.Y));
 
             // Pack probe properties buffer
             probe.SetShaderData(data.PData);
@@ -368,7 +368,7 @@ void ReflectionsPass::Render(RenderContext& renderContext, GPUTextureView* light
         context->UnBindSR(4);
         context->ResetRenderTarget();
         if (_depthBounds)
-            context->SetDepthBounds(0, 1);
+            context->SetDepthBounds();
     }
 
     // Screen Space Reflections pass
@@ -417,7 +417,7 @@ void ReflectionsPass::Render(RenderContext& renderContext, GPUTextureView* light
         if (_depthBounds)
         {
             context->SetRenderTarget(depthBufferRTV, lightBuffer);
-            context->SetDepthBounds(0, RenderTools::DepthBoundMaxBackground);
+            context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(GPU_DEPTH_MIN_VALUE, RenderTools::DepthBoundMaxBackground));
         }
         else
             context->SetRenderTarget(lightBuffer);
@@ -430,7 +430,7 @@ void ReflectionsPass::Render(RenderContext& renderContext, GPUTextureView* light
         context->SetState(_psCombinePass);
         context->DrawFullscreenTriangle();
         if (_depthBounds)
-            context->SetDepthBounds(0, 1);
+            context->SetDepthBounds();
     }
 
     RenderTargetPool::Release(ssrBuffer);

Source/Engine/Renderer/ShadowsPass.cpp

@@ -1147,11 +1147,7 @@ void ShadowsPass::SetupLight(ShadowsCustomBuffer& shadows, RenderContext& render
 void ShadowsPass::ClearShadowMapTile(GPUContext* context, GPUConstantBuffer* quadShaderCB, QuadShaderData& quadShaderData) const
 {
     // Color.r is used by PS_DepthClear in Quad shader to clear depth
-#if FLAX_REVERSE_Z
+    quadShaderData.Color = GPU_DEPTH_MAX_VALUE;
-    quadShaderData.Color = Float4::Zero;
-#else
-    quadShaderData.Color = Float4::One;
-#endif
     context->UpdateCB(quadShaderCB, &quadShaderData);
     context->BindCB(0, quadShaderCB);
 
@@ -1753,8 +1749,8 @@ void ShadowsPass::RenderShadowMask(RenderContextBatch& renderContextBatch, Rende
         if (light.IsPointLight || light.IsSpotLight)
             minMaxDepth = RenderTools::GetDepthBounds(view, BoundingSphere(light.Position, ((RenderLocalLightData&)light).Radius));
         else //if (light.IsDirectionalLight)
-            minMaxDepth = Float2(0.0f, RenderTools::DepthBoundMaxBackground);
+            minMaxDepth = Float2(GPU_DEPTH_MIN_VALUE, RenderTools::DepthBoundMaxBackground);
-        context->SetDepthBounds(minMaxDepth.X, minMaxDepth.Y);
+        context->SetDepthBounds(GPU_DEPTH_BOUNDS_SWAP(minMaxDepth.X, minMaxDepth.Y));
     }
     if (light.IsPointLight)
     {