From 494a639782ac5b08ecc9b4101f34b6d72ecaf11f Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Mon, 22 Jun 2026 13:52:08 +0200
Subject: [PATCH] Fix Debug Draw shapes manual depth test when using resolution
 upscaling

---
 Source/Engine/Debug/DebugDraw.cpp | 5 ++++-
 Source/Shaders/DebugDraw.shader   | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Source/Engine/Debug/DebugDraw.cpp b/Source/Engine/Debug/DebugDraw.cpp
index 18552dcec..a4febc613 100644
--- a/Source/Engine/Debug/DebugDraw.cpp
+++ b/Source/Engine/Debug/DebugDraw.cpp
@@ -136,7 +136,7 @@ typedef DebugDraw::Vertex Vertex;
 
 GPU_CB_STRUCT(ShaderData {
     Matrix ViewProjection;
-    Float2 Padding;
+    Float2 SceneDepthUVScale;
     float ClipPosZBias;
     uint32 EnableDepthTest;
     });
@@ -861,6 +861,9 @@ void DebugDraw::Draw(RenderContext& renderContext, GPUTextureView* target, GPUTe
     Matrix::Multiply(view.View, view.Projection, vp);
     Matrix::Transpose(vp, data.ViewProjection);
     data.ClipPosZBias = view.IsPerspectiveProjection() ? -0.2f : 0.0f; // Reduce Z-fighting artifacts (eg. editor grid)
+    data.SceneDepthUVScale = Float2::One;
+    if (enableDepthTest && renderContext.Buffers->DepthBuffer && target && ScriptingObject::Cast<GPUTexture>(target->GetParent()))
+        data.SceneDepthUVScale = renderContext.Buffers->DepthBuffer->Size() / ((GPUTexture*)target->GetParent())->Size();
     data.EnableDepthTest = enableDepthTest;
     context->UpdateCB(cb, &data);
     context->BindCB(0, cb);
diff --git a/Source/Shaders/DebugDraw.shader b/Source/Shaders/DebugDraw.shader
index 62576dd17..5994a111c 100644
--- a/Source/Shaders/DebugDraw.shader
+++ b/Source/Shaders/DebugDraw.shader
@@ -4,7 +4,7 @@
 
 META_CB_BEGIN(0, Data)
 float4x4 ViewProjection;
-float2 Padding;
+float2 SceneDepthUVScale;
 float ClipPosZBias;
 bool EnableDepthTest;
 META_CB_END
@@ -39,7 +39,7 @@ float4 PS(VS2PS input) : SV_Target
 	FLATTEN
 	if (EnableDepthTest)
 	{
-		float sceneDepthDeviceZ = SceneDepthTexture.Load(int3(input.Position.xy, 0)).r;
+		float sceneDepthDeviceZ = SceneDepthTexture.Load(int3(input.Position.xy * SceneDepthUVScale, 0)).r;
 		float interpolatedDeviceZ = input.Position.z;
 		clip(DEPTH_DIFF(sceneDepthDeviceZ, interpolatedDeviceZ));
 	}