Coordinate Grid: support inverse depth

Author: TheMostDiligent

Components/interface/CoordinateGridRenderer.hpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2024 Diligent Graphics LLC
+ *  Copyright 2024-2025 Diligent Graphics LLC
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -53,14 +53,13 @@ class CoordinateGridRenderer
     enum FEATURE_FLAGS : Uint32
     {
         FEATURE_FLAG_NONE            = 0u,
-        FEATURE_FLAG_REVERSED_DEPTH  = 1u << 0u,
-        FEATURE_FLAG_CONVERT_TO_SRGB = 1u << 1u,
-        FEATURE_FLAG_RENDER_PLANE_YZ = 1u << 2u,
-        FEATURE_FLAG_RENDER_PLANE_XZ = 1u << 3u,
-        FEATURE_FLAG_RENDER_PLANE_XY = 1u << 4u,
-        FEATURE_FLAG_RENDER_AXIS_X   = 1u << 5u,
-        FEATURE_FLAG_RENDER_AXIS_Y   = 1u << 6u,
-        FEATURE_FLAG_RENDER_AXIS_Z   = 1u << 7u,
+        FEATURE_FLAG_CONVERT_TO_SRGB = 1u << 0u,
+        FEATURE_FLAG_RENDER_PLANE_YZ = 1u << 1u,
+        FEATURE_FLAG_RENDER_PLANE_XZ = 1u << 2u,
+        FEATURE_FLAG_RENDER_PLANE_XY = 1u << 3u,
+        FEATURE_FLAG_RENDER_AXIS_X   = 1u << 4u,
+        FEATURE_FLAG_RENDER_AXIS_Y   = 1u << 5u,
+        FEATURE_FLAG_RENDER_AXIS_Z   = 1u << 6u,
     };
 
     struct RenderAttributes

Components/src/CoordinateGridRenderer.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2024 Diligent Graphics LLC
+ *  Copyright 2024-2025 Diligent Graphics LLC
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -220,7 +220,6 @@ bool CoordinateGridRenderer::UpdateUI(HLSL::CoordinateGridAttribs& Attribs, Coor
 
 void CoordinateGridRenderer::AddShaderMacros(FEATURE_FLAGS FeatureFlags, ShaderMacroHelper& Macros)
 {
-    Macros.Add("COORDINATE_GRID_INVERTED_DEPTH", (FeatureFlags & FEATURE_FLAG_REVERSED_DEPTH) != 0);
     Macros.Add("COORDINATE_GRID_CONVERT_OUTPUT_TO_SRGB", (FeatureFlags & FEATURE_FLAG_CONVERT_TO_SRGB) != 0);
 
     Macros.Add("COORDINATE_GRID_AXIS_X", (FeatureFlags & FEATURE_FLAG_RENDER_AXIS_X) != 0);

Hydrogent/src/Tasks/HnBeginFrameTask.cpp

@@ -548,7 +548,8 @@ void HnBeginFrameTask::UpdateFrameConstants(IDeviceContext* pCtx,
             CamAttribs.f2Jitter   = Jitter;
             CamAttribs.fFStop     = m_pCamera->GetFStop();
 
-            const float MetersPerUnit = RenderParam ? RenderParam->GetConfig().MetersPerUnit : 0.01f;
+            const HnRenderParam::Configuration& RenderConfig  = RenderParam->GetConfig();
+            const float                         MetersPerUnit = RenderConfig.MetersPerUnit;
 
             // USD camera properties are measured in scene units, but Diligent camera expects them in world units.
             CamAttribs.fFocusDistance = m_pCamera->GetFocusDistance() * MetersPerUnit;
@@ -574,7 +575,22 @@ void HnBeginFrameTask::UpdateFrameConstants(IDeviceContext* pCtx,
             CamAttribs.fFocalLength  = m_pCamera->GetFocalLength() * MillimetersPerUnit;
             CamAttribs.fExposure     = m_pCamera->GetExposure();
 
-            ProjMatrix.GetNearFarClipPlanes(CamAttribs.fNearPlaneZ, CamAttribs.fFarPlaneZ, pDevice->GetDeviceInfo().NDC.MinZ == -1);
+            float fNearPlaneZ, fFarPlaneZ;
+            ProjMatrix.GetNearFarClipPlanes(fNearPlaneZ, fFarPlaneZ, pDevice->GetDeviceInfo().NDC.MinZ == -1);
+            if (RenderConfig.UseReverseDepth)
+            {
+                CamAttribs.fNearPlaneZ     = fFarPlaneZ;
+                CamAttribs.fFarPlaneZ      = fNearPlaneZ;
+                CamAttribs.fNearPlaneDepth = 1.f;
+                CamAttribs.fFarPlaneDepth  = 0.f;
+            }
+            else
+            {
+                CamAttribs.fNearPlaneZ     = fNearPlaneZ;
+                CamAttribs.fFarPlaneZ      = fFarPlaneZ;
+                CamAttribs.fNearPlaneDepth = 0.f;
+                CamAttribs.fFarPlaneDepth  = 1.f;
+            }
 
             if (CamAttribs.mView != PrevCamera.mView)
             {

Shaders/Common/public/BasicStructures.fxh

@@ -88,8 +88,13 @@ struct CameraAttribs
 
     float fNearPlaneZ; 
     float fFarPlaneZ;  // fNearPlaneZ < fFarPlaneZ
+    float fNearPlaneDepth;
+    float fFarPlaneDepth;
+    
     float fHandness;   // +1.0 for right-handed coordinate system, -1.0 for left-handed
     uint  uiFrameIndex;
+    float Padding0;
+    float Padding1;
 
     // Distance to the point of focus
     float fFocusDistance DEFAULT_VALUE(10.0f); 

Shaders/Common/public/CoordinateGrid.fxh

@@ -4,18 +4,6 @@
 #include "CoordinateGridStructures.fxh"
 #include "ShaderUtilities.fxh"
 
-#if COORDINATE_GRID_INVERTED_DEPTH
-    #define DepthNearPlane     1.0
-    #define DepthFarPlane      0.0
-    #define DepthMin           max
-    #define DepthCompare(x, y) ((x)>(y))
-#else
-    #define DepthNearPlane     0.0
-    #define DepthFarPlane      1.0
-    #define DepthMin           min
-    #define DepthCompare(x, y) ((x)<(y))
-#endif // COORDINATE_GRID_INVERTED_DEPTH
-
 struct Ray
 {
     float3 Origin;
@@ -25,11 +13,13 @@ struct Ray
 Ray CreateCameraRay(float2   NormalizedXY,
                     float4x4 CameraProj,
                     float4x4 CameraViewProjInv,
-                    float3   CameraPosition)
+                    float3   CameraPosition,
+                    float    NearPlaneDepth,
+                    float    FarPlaneDepth)
 {
     Ray CameraRay;
-    float4 RayStart = mul(float4(NormalizedXY, DepthToNormalizedDeviceZ(DepthNearPlane), 1.0f), CameraViewProjInv);
-    float4 RayEnd   = mul(float4(NormalizedXY, DepthToNormalizedDeviceZ(DepthFarPlane),  1.0f), CameraViewProjInv);
+    float4 RayStart = mul(float4(NormalizedXY, DepthToNormalizedDeviceZ(NearPlaneDepth), 1.0f), CameraViewProjInv);
+    float4 RayEnd   = mul(float4(NormalizedXY, DepthToNormalizedDeviceZ(FarPlaneDepth),  1.0f), CameraViewProjInv);
 
     RayStart.xyz /= RayStart.w;
     RayEnd.xyz   /= RayEnd.w;
@@ -171,7 +161,7 @@ float4 ComputeCoordinateGrid(in float2                f2NormalizedXY,
                              in float                 MaxDepth,
                              in CoordinateGridAttribs GridAttribs)
 {
-    Ray RayWS = CreateCameraRay(f2NormalizedXY, Camera.mProj, Camera.mViewProjInv, Camera.f4Position.xyz);
+    Ray RayWS = CreateCameraRay(f2NormalizedXY, Camera.mProj, Camera.mViewProjInv, Camera.f4Position.xyz, Camera.fNearPlaneDepth, Camera.fFarPlaneDepth);
 
     float3 Positions[3];
     float  PlaneAlpha[3];