---
title: RDG Debug笔记
date: 2025-06-14 15:44:47
excerpt: 
tags: 
rating: ⭐
---
# 前言
- [UE5 Render Dependency Graph-实用指南](https://zhuanlan.zhihu.com/p/637889120)

# Command
- r.rdg
	- AsyncCompute 
	- BreakPoint

## Reference
```c++
FAutoConsoleVariableRef CVarRDGDebug(  
    TEXT("r.RDG.Debug"),  
    GRDGDebug,  
    TEXT("Allow to output warnings for inefficiencies found during wiring and execution of the passes.\n")  
    TEXT(" 0: disabled;\n")  
    TEXT(" 1: emit warning once (default);\n")  
    TEXT(" 2: emit warning everytime issue is detected."),  
    ECVF_RenderThreadSafe);
    
FAutoConsoleVariableRef CVarRDGClobberResources(  
    TEXT("r.RDG.ClobberResources"),  
    GRDGClobberResources,  
    TEXT("Clears all render targets and texture / buffer UAVs with the requested clear color at allocation time. Useful for debugging.\n")  
    TEXT(" 0:off (default);\n")  
    TEXT(" 1: 1000 on RGBA channels;\n")  
    TEXT(" 2: NaN on RGBA channels;\n")  
    TEXT(" 3: +INFINITY on RGBA channels.\n"),  
    ECVF_Cheat | ECVF_RenderThreadSafe);
    
FAutoConsoleVariableRef CVarRDGOverlapUAVs(  
    TEXT("r.RDG.OverlapUAVs"), GRDGOverlapUAVs,  
    TEXT("RDG will overlap UAV work when requested; if disabled, UAV barriers are always inserted."),  
    ECVF_RenderThreadSafe);
    
FAutoConsoleVariableRef CVarRDGTransitionLog(  
    TEXT("r.RDG.TransitionLog"), GRDGTransitionLog,  
    TEXT("Logs resource transitions to the console.\n")  
    TEXT(" 0: disabled(default);\n")  
    TEXT(">0: enabled for N frames;\n")  
    TEXT("<0: enabled;\n"),  
    ECVF_RenderThreadSafe);
    
TAutoConsoleVariable<FString> CVarRDGDebugPassFilter(  
    TEXT("r.RDG.Debug.PassFilter"), TEXT(""),  
    TEXT("Filters certain debug events to specific passes. Set to 'None' to reset.\n"),  
    ECVF_Default);
    
TAutoConsoleVariable<FString> CVarRDGDebugResourceFilter(  
    TEXT("r.RDG.Debug.ResourceFilter"), TEXT(""),  
    TEXT("Filters certain debug events to a specific resource. Set to 'None' to reset.\n"),  
    ECVF_Default);

FAutoConsoleVariableRef CVarRDGParallelSetup(  
    TEXT("r.RDG.ParallelSetup"), GRDGParallelSetup,  
    TEXT("RDG will setup passes in parallel when prompted by calls to FRDGBuilder::FlushSetupQueue.")  
    TEXT(" 0: pass setup is done synchronously in AddPass;")  
    TEXT(" 1: pass setup is done asynchronously (default);"),  
    ECVF_RenderThreadSafe);
```

# Visualize Texture Integration
**vis**  
使用vis指令，可以打印vis指令帮助信息，以及当前帧使用到的所有的资源信息

![[RDG_Vis.jpg|1200]]

**vis [RT Name]**  
使用vis [RT Name]可以实时预览当前RT的内容，在调试渲染特性的时候可以很方便的Debug

![[RDG_Vis_RTName.jpg|800]]

**vis [RT Name] bump**  
打印当前RT到Saved/Screenshots  
  
**vis off**  
关闭当前帧的debug模式

# r.RDG.ImmediateMode
将RDG设置成理解执行模式，方便进行资源绑定Debug以及断点。
- RDG立即执行模式:
	- 立刻执行Pass在其被添加的时候
	- 产生和延后执行时一样的功能
	- 如果打断点，会非常容易检查其创建的代码
	- 由于这个原因，所以不能在AddPass后再去更改Pass参数
	- 可以利用r.RDG.ImmediateMode在运行时切换
	- 会消耗更多的内存，可以考虑使用r.Test.SecondaryUpscaleOverride运行在低分辨率下。（r.Test.SecondaryUpscaleOverride 设置的参数越大越模糊）

![[RDG_Immediate.png|800]]

- **r.RDG.ImmediateMode 1** / -rdgimmediate : 去除RDG的影响  
- **r.RHICmdBypass 1** ：去除RHI和并行渲染的影响
- r.RDG.ParallelExecute=0
- r.RDG.ParallelSetup=0

## RDG Async Compute
1.直接设置ComputePassFlags为ERDGPassFlags::AsyncCompute，剩下的工作交给RDG自动判断和设置
```c++
ERDGPassFlags ComputePassFlags = (GSupportsEfficientAsyncCompute && CVarTSRAsyncCompute.GetValueOnRenderThread() != 0) ? ERDGPassFlags::AsyncCompute : ERDGPassFlags::Compute;

TShaderMapRef<FTSRClearPrevTexturesCS> ComputeShader(View.ShaderMap);
                FComputeShaderUtils::AddPass(
                        GraphBuilder,
                        RDG_EVENT_NAME("TSR ClearPrevTextures %dx%d", InputRect.Width(), InputRect.Height()),
                        ComputePassFlags,
                        ComputeShader,
                        PassParameters,
                        FComputeShaderUtils::GetGroupCount(InputRect.Size(), 8 * 2));
```

2.在Render层调整Pass顺序，为RDG提供更多Async Compute Overlap的可能性

# ValidateShaderParameters
ValidateShaderParameters()可以检测RDG绑定的资源是否都存在。

# -rdgdebug
`r.RDG.Debug = 1`来开启。

# RDG Insight
开启RDG Insight Plugin之后即可在UnrealInsight看到额外添加RDG Channel。

命令行启动游戏：  
`Game.exe -trace=rdg,defaults`

# DumpGPU
使用DumpGPU指令可以将当前帧的所有Pass和资源信息打印，可以很方便的进行查看。  
在Console中输入DumpGPU指令，会弹出生成好的html文件：  

![](https://pica.zhimg.com/v2-675aa8a985ccd280ef78e7578d509f16_1440w.jpg)

  
执行OpenGPUDumpViewer.bat打开网页，默认只支持chrome浏览器，可以通过修改脚本调用别的浏览器：
![](https://pic1.zhimg.com/v2-2fb3021428caca29b8c41b2cb01a0f26_1440w.jpg)

  
可以看到各个Pass的信息：  

![](https://pic1.zhimg.com/v2-3732fc0379732e15eaf15d341b08586c_1440w.jpg)

  
显示当前帧所有CVar的值：  

![](https://pica.zhimg.com/v2-79ba2f962e6167dfec0f88f08ac3c2aa_1440w.jpg)

  
比较像素的值：  

![](https://picx.zhimg.com/v2-16e264f19d4c0d98b3942fb485115ecf_1440w.jpg)