From 1b6a31b6e5005ab67c4e97c9dfadeb669d6e9bdb Mon Sep 17 00:00:00 2001
From: ExMatics HydrogenC <33123710+HydrogenC@users.noreply.github.com>
Date: Wed, 5 Jun 2024 21:15:08 +0800
Subject: [PATCH] Finish conditional compiling

---
 Source/Engine/Renderer/GBufferPass.cpp | 5 ++++-
 Source/Shaders/Common.hlsl             | 9 ++++++++-
 Source/Shaders/DebugDraw.shader        | 4 ++++
 Source/Shaders/GBuffer.hlsl            | 2 +-
 Source/Shaders/SSR.hlsl                | 4 ++++
 5 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/Source/Engine/Renderer/GBufferPass.cpp b/Source/Engine/Renderer/GBufferPass.cpp
index 96201807b..bf41b6117 100644
--- a/Source/Engine/Renderer/GBufferPass.cpp
+++ b/Source/Engine/Renderer/GBufferPass.cpp
@@ -396,7 +396,10 @@ bool GBufferPass::IsDebugView(ViewMode mode)
 void GBufferPass::SetInputs(const RenderView& view, GBufferData& gBuffer)
 {
     // GBuffer params:
-    // ViewInfo             :  x-1/Projection[0,0]   y-1/Projection[1,1]   z-(Near / (Far - Near))   w-((Far * Near) / (Far - Near) / Far)
+    // With reverse Z enabled: 
+    // ViewInfo             :  x-1/Projection[0,0]   y-1/Projection[1,1]   z-(-(Near / (Far - Near))   w-((Far * Near) / (Far - Near) / Far)
+    // Otherwise:
+    // ViewInfo             :  x-1/Projection[0,0]   y-1/Projection[1,1]   z-(Far / (Far - Near))   w-(-(Far * Near) / (Far - Near) / Far)
     // ScreenSize           :  x-Width               y-Height              z-1 / Width             w-1 / Height
     // ViewPos,ViewFar      :  x,y,z - world space view position                                   w-Far
     // InvViewMatrix        :  inverse view matrix (4 rows by 4 columns)
diff --git a/Source/Shaders/Common.hlsl b/Source/Shaders/Common.hlsl
index 701546761..d0c5ee858 100644
--- a/Source/Shaders/Common.hlsl
+++ b/Source/Shaders/Common.hlsl
@@ -53,6 +53,9 @@
 #define SHADING_MODEL_SUBSURFACE 2
 #define SHADING_MODEL_FOLIAGE 3
 
+// Didn't figure out how to pass compilation flags via C++, so hardcode it temporarily
+#define FLAX_REVERSE_Z 1
+
 // Detect feature level support
 #if FEATURE_LEVEL >= FEATURE_LEVEL_SM5
 #define CAN_USE_GATHER 1
@@ -135,7 +138,11 @@ SamplerComparisonState ShadowSamplerPCF : register(s5);
 // Structure that contains information about GBuffer
 struct GBufferData
 {
-    float4 ViewInfo; // x-1/Projection[0,0], y-1/Projection[1,1], z-(Near / (Far - Near)), w-((Far * Near) / (Far - Near) / Far)
+    // If reverse Z enabled:
+    // x-1/Projection[0,0], y-1/Projection[1,1], z-(-Near / (Far - Near)), w-((Far * Near) / (Far - Near) / Far)
+    // Otherwise: 
+    // x-1/Projection[0,0], y-1/Projection[1,1], z-(Far / (Far - Near)), w-(-(Far * Near) / (Far - Near) / Far)
+    float4 ViewInfo; 
     float4 ScreenSize; // x-Width, y-Height, z-1/Width, w-1/Height
     float3 ViewPos; // view position (in world space)
     float ViewFar; // view far plane distance (in world space)
diff --git a/Source/Shaders/DebugDraw.shader b/Source/Shaders/DebugDraw.shader
index de4e079be..81b85c1a1 100644
--- a/Source/Shaders/DebugDraw.shader
+++ b/Source/Shaders/DebugDraw.shader
@@ -43,7 +43,11 @@ float4 PS(VS2PS input) : SV_Target
 	{
 		float sceneDepthDeviceZ = SceneDepthTexture.Load(int3(input.Position.xy, 0)).r;
 		float interpolatedDeviceZ = input.Position.z;
+#if FLAX_REVERSE_Z
 		clip(interpolatedDeviceZ - sceneDepthDeviceZ);
+#else
+		clip(sceneDepthDeviceZ - interpolatedDeviceZ);
+#endif
 	}
 #endif
 
diff --git a/Source/Shaders/GBuffer.hlsl b/Source/Shaders/GBuffer.hlsl
index 0dd2c4457..9378b3be5 100644
--- a/Source/Shaders/GBuffer.hlsl
+++ b/Source/Shaders/GBuffer.hlsl
@@ -33,7 +33,7 @@ float LinearizeZ(GBufferData gBuffer, float depth)
 // Convert linear depth to device depth
 float LinearZ2DeviceDepth(GBufferData gBuffer, float linearDepth)
 {
-    return ((gBuffer.ViewInfo.w / linearDepth) + gBuffer.ViewInfo.z);
+    return (gBuffer.ViewInfo.w / linearDepth) + gBuffer.ViewInfo.z;
 }
 
 // Get view space position at given pixel coordinate with given device depth
diff --git a/Source/Shaders/SSR.hlsl b/Source/Shaders/SSR.hlsl
index 0adf84a83..8cef82789 100644
--- a/Source/Shaders/SSR.hlsl
+++ b/Source/Shaders/SSR.hlsl
@@ -98,7 +98,11 @@ float3 TraceScreenSpaceReflection(float2 uv, GBufferSample gBuffer, Texture2D de
     {
         // Sample depth buffer and calculate depth difference
         currSample = SAMPLE_RT(depthBuffer, currOffset.xy).r;
+#if FLAX_REVERSE_Z
         depthDiff = currSample - currOffset.z;
+#else
+        depthDiff = currOffset.z - currSample;
+#endif
 
         // Check intersection
         if (depthDiff >= 0)