From b34ab9b377152bbf6cccdfb22b8f0ab78c0b1d41 Mon Sep 17 00:00:00 2001
From: Johann Muszynski <johann.muszynski@gmail.com>
Date: Thu, 28 Mar 2024 09:33:25 +0200
Subject: [PATCH] Visualize depth buffer in debug pass

---
 src/pt/hybrid_renderer.cpp             | 19 +++++++++++--------
 src/pt/hybrid_renderer_debug_pass.wgsl | 10 ++++++++--
 src/pt/shader_source.hpp               | 10 ++++++++--
 3 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/src/pt/hybrid_renderer.cpp b/src/pt/hybrid_renderer.cpp
index e9a0677..7cf316c 100644
--- a/src/pt/hybrid_renderer.cpp
+++ b/src/pt/hybrid_renderer.cpp
@@ -80,7 +80,7 @@ HybridRenderer::HybridRenderer(
         const WGPUTextureDescriptor depthTextureDesc{
             .nextInChain = nullptr,
             .label = "Depth texture",
-            .usage = WGPUTextureUsage_RenderAttachment,
+            .usage = WGPUTextureUsage_RenderAttachment | WGPUTextureUsage_TextureBinding,
             .dimension = WGPUTextureDimension_2D,
             .size = {rendererDesc.framebufferSize.x, rendererDesc.framebufferSize.y, 1},
             .format = DEPTH_TEXTURE_FORMAT,
@@ -134,17 +134,19 @@ HybridRenderer::HybridRenderer(
     mGbufferBindGroupLayout = GpuBindGroupLayout{
         gpuContext.device,
         "Gbuffer bind group layout",
-        std::array<WGPUBindGroupLayoutEntry, 2>{
+        std::array<WGPUBindGroupLayoutEntry, 3>{
             textureBindGroupLayoutEntry(0, WGPUTextureSampleType_UnfilterableFloat),
-            textureBindGroupLayoutEntry(1, WGPUTextureSampleType_UnfilterableFloat)}};
+            textureBindGroupLayoutEntry(1, WGPUTextureSampleType_UnfilterableFloat),
+            textureBindGroupLayoutEntry(2, WGPUTextureSampleType_Depth)}};
 
     mGbufferBindGroup = GpuBindGroup{
         gpuContext.device,
         "Gbuffer bind group",
         mGbufferBindGroupLayout.ptr(),
-        std::array<WGPUBindGroupEntry, 2>{
+        std::array<WGPUBindGroupEntry, 3>{
             textureBindGroupEntry(0, mAlbedoTextureView),
-            textureBindGroupEntry(1, mNormalTextureView)}};
+            textureBindGroupEntry(1, mNormalTextureView),
+            textureBindGroupEntry(2, mDepthTextureView)}};
 
     mDebugPass = DebugPass{gpuContext, mGbufferBindGroupLayout, rendererDesc.framebufferSize};
 }
@@ -227,7 +229,7 @@ void HybridRenderer::resize(const GpuContext& gpuContext, const Extent2u& newSiz
         const WGPUTextureDescriptor depthTextureDesc{
             .nextInChain = nullptr,
             .label = "Depth texture",
-            .usage = WGPUTextureUsage_RenderAttachment,
+            .usage = WGPUTextureUsage_RenderAttachment | WGPUTextureUsage_TextureBinding,
             .dimension = WGPUTextureDimension_2D,
             .size = {newSize.x, newSize.y, 1},
             .format = DEPTH_TEXTURE_FORMAT,
@@ -282,9 +284,10 @@ void HybridRenderer::resize(const GpuContext& gpuContext, const Extent2u& newSiz
         gpuContext.device,
         "Gbuffer bind group",
         mGbufferBindGroupLayout.ptr(),
-        std::array<WGPUBindGroupEntry, 2>{
+        std::array<WGPUBindGroupEntry, 3>{
             textureBindGroupEntry(0, mAlbedoTextureView),
-            textureBindGroupEntry(1, mNormalTextureView)}};
+            textureBindGroupEntry(1, mNormalTextureView),
+            textureBindGroupEntry(2, mDepthTextureView)}};
 }
 
 HybridRenderer::GbufferPass::GbufferPass(
diff --git a/src/pt/hybrid_renderer_debug_pass.wgsl b/src/pt/hybrid_renderer_debug_pass.wgsl
index 4c2d03c..cbc0721 100644
--- a/src/pt/hybrid_renderer_debug_pass.wgsl
+++ b/src/pt/hybrid_renderer_debug_pass.wgsl
@@ -20,15 +20,21 @@ fn vsMain(in: VertexInput) -> VertexOutput {
 @group(0) @binding(0) var<uniform> framebufferSize: vec2f;
 @group(1) @binding(0) var gbufferAlbedo: texture_2d<f32>;
 @group(1) @binding(1) var gbufferNormal: texture_2d<f32>;
+@group(1) @binding(2) var gbufferDepth: texture_depth_2d;
 
 @fragment
 fn fsMain(in: VertexOutput) -> @location(0) vec4f {
     let c = in.texCoord;
     let idx = vec2u(floor(c * framebufferSize));
-    if c.x < 0.5 {
+    if c.x < 0.333 {
         return textureLoad(gbufferAlbedo, idx, 0);
-    } else {
+    } else if c.x < 0.666 {
         let n = textureLoad(gbufferNormal, idx, 0);
         return vec4(vec3(0.5) * (n.xyz + vec3(1f)), 1.0);
+    } else {
+        let d = vec3(1.0) - textureLoad(gbufferDepth, idx, 0);
+        let x = d;
+        let a = 0.05;
+        return vec4((1.0 + a) * x / (x + vec3(a)), 1.0);
     }
 }
diff --git a/src/pt/shader_source.hpp b/src/pt/shader_source.hpp
index 02d984e..198045d 100644
--- a/src/pt/shader_source.hpp
+++ b/src/pt/shader_source.hpp
@@ -759,16 +759,22 @@ fn vsMain(in: VertexInput) -> VertexOutput {
 @group(0) @binding(0) var<uniform> framebufferSize: vec2f;
 @group(1) @binding(0) var gbufferAlbedo: texture_2d<f32>;
 @group(1) @binding(1) var gbufferNormal: texture_2d<f32>;
+@group(1) @binding(2) var gbufferDepth: texture_depth_2d;
 
 @fragment
 fn fsMain(in: VertexOutput) -> @location(0) vec4f {
     let c = in.texCoord;
     let idx = vec2u(floor(c * framebufferSize));
-    if c.x < 0.5 {
+    if c.x < 0.333 {
         return textureLoad(gbufferAlbedo, idx, 0);
-    } else {
+    } else if c.x < 0.666 {
         let n = textureLoad(gbufferNormal, idx, 0);
         return vec4(vec3(0.5) * (n.xyz + vec3(1f)), 1.0);
+    } else {
+        let d = vec3(1.0) - textureLoad(gbufferDepth, idx, 0);
+        let x = d;
+        let a = 0.05;
+        return vec4((1.0 + a) * x / (x + vec3(a)), 1.0);
     }
 }
 )";