bSupportsDxc

bSupportsDxc

#Overview

name: bSupportsDxc

The value of this variable can be defined or overridden in .ini config files. 8 .ini config files referencing this setting variable.

It is referenced in 4 C++ source files.

#Summary

#Usage in the C++ source code

The purpose of bSupportsDxc is to indicate whether the DirectX Shader Compiler (DXC) is supported for a specific shader platform in Unreal Engine 5. This variable is part of the shader compilation and rendering system.

The Unreal Engine subsystem that primarily relies on this setting variable is the Rendering Hardware Interface (RHI) module. This can be seen from the file locations where the variable is referenced, which are all within the RHI module.

The value of this variable is set through the data-driven shader platform information system. It’s parsed from a configuration section in the ParseDataDrivenShaderInfo function and can be updated for preview platforms in the UpdatePreviewPlatforms function.

This variable interacts with other shader platform-related variables such as bIsHlslcc, bIsSPIRV, and Language. These variables collectively define the characteristics and capabilities of a shader platform.

Developers must be aware that this variable is platform-specific and its value can affect shader compilation processes. It’s particularly important when working on cross-platform projects or when targeting platforms that may or may not support DXC.

Best practices when using this variable include:

1. Always check its value before attempting to use DXC for shader compilation.
2. Consider providing fallback options for platforms where DXC is not supported.
3. Use the provided GetSupportsDxc function to query this value, rather than accessing the variable directly.
4. Be aware of how this setting interacts with other shader platform settings to ensure consistent behavior across different platforms.
5. When defining custom shader platforms, ensure this value is correctly set to reflect the platform’s capabilities.

#Setting Variables

#References In INI files

Location: <Workspace>/Engine/Config/Android/DataDrivenPlatformInfo.ini:70, section: [ShaderPlatform OPENGL_ES3_1_ANDROID]

• INI Section: ShaderPlatform OPENGL_ES3_1_ANDROID
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/Android/DataDrivenPlatformInfo.ini:92, section: [ShaderPlatform VULKAN_ES3_1_ANDROID]

• INI Section: ShaderPlatform VULKAN_ES3_1_ANDROID
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/Android/DataDrivenPlatformInfo.ini:123, section: [ShaderPlatform VULKAN_SM5_ANDROID]

• INI Section: ShaderPlatform VULKAN_SM5_ANDROID
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/Mac/DataDrivenPlatformInfo.ini:45, section: [ShaderPlatform METAL_SM5]

• INI Section: ShaderPlatform METAL_SM5
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/Mac/DataDrivenPlatformInfo.ini:85, section: [ShaderPlatform METAL_SM6]

• INI Section: ShaderPlatform METAL_SM6
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/VulkanPC/DataDrivenPlatformInfo.ini:21, section: [ShaderPlatform VULKAN_SM5]

• INI Section: ShaderPlatform VULKAN_SM5
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/VulkanPC/DataDrivenPlatformInfo.ini:152, section: [ShaderPlatform VULKAN_SM6]

• INI Section: ShaderPlatform VULKAN_SM6
• Raw value: true
• Is Array: False

Location: <Workspace>/Engine/Config/Windows/DataDrivenPlatformInfo.ini:111, section: [ShaderPlatform PCD3D_SM6]

• INI Section: ShaderPlatform PCD3D_SM6
• Raw value: true
• Is Array: False

#References in C++ code

#Callsites

This variable is referenced in the following C++ source code:

#Loc: <Workspace>/Engine/Source/Runtime/RHI/Private/DataDrivenShaderPlatformInfo.cpp:262

Scope (from outer to inner):

file
function     void FGenericDataDrivenShaderPlatformInfo::ParseDataDrivenShaderInfo

Source code excerpt:

	GET_SECTION_BOOL_HELPER(bSupportsPerPixelDBufferMask);
	GET_SECTION_BOOL_HELPER(bIsHlslcc);
	GET_SECTION_BOOL_HELPER(bSupportsDxc);
	GET_SECTION_BOOL_HELPER(bSupportsVariableRateShading);
	GET_SECTION_BOOL_HELPER(bIsSPIRV);
	GET_SECTION_INT_HELPER(NumberOfComputeThreads);

	GET_SECTION_BOOL_HELPER(bWaterUsesSimpleForwardShading);
	GET_SECTION_BOOL_HELPER(bSupportsHairStrandGeometry);

#Loc: <Workspace>/Engine/Source/Runtime/RHI/Private/DataDrivenShaderPlatformInfo.cpp:436

Scope (from outer to inner):

file
function     void FGenericDataDrivenShaderPlatformInfo::UpdatePreviewPlatforms

Source code excerpt:

				PREVIEW_USE_RUNTIME_VALUE(Language);
				PREVIEW_USE_RUNTIME_VALUE(bIsHlslcc);
				PREVIEW_USE_RUNTIME_VALUE(bSupportsDxc);

				// Editor is always PC, never console and always supports debug view shaders
				PREVIEW_FORCE_SETTING(bIsPC, true);
				PREVIEW_FORCE_SETTING(bSupportsDebugViewShaders, true);
				PREVIEW_FORCE_SETTING(bIsConsole, false);

#Loc: <Workspace>/Engine/Source/Runtime/RHI/Public/DataDrivenShaderPlatformInfo.h:86

Scope (from outer to inner):

file
class        class FGenericDataDrivenShaderPlatformInfo

Source code excerpt:

	uint32 bSupportsPerPixelDBufferMask : 1;
	uint32 bIsHlslcc : 1;
	uint32 bSupportsDxc : 1; // Whether DirectXShaderCompiler (DXC) is supported
	uint32 bIsSPIRV : 1;
	uint32 bSupportsVariableRateShading : 1;
	uint32 NumberOfComputeThreads : 10;
	uint32 bWaterUsesSimpleForwardShading : 1;
	uint32 bSupportsHairStrandGeometry : 1;
	uint32 bSupportsDOFHybridScattering : 1;

#Loc: <Workspace>/Engine/Source/Runtime/RHI/Public/DataDrivenShaderPlatformInfo.h:599

Scope (from outer to inner):

file
class        class FGenericDataDrivenShaderPlatformInfo
function     static const bool GetSupportsDxc

Source code excerpt:

	{
		check(IsValid(Platform));
		return Infos[Platform].bSupportsDxc;
	}

	static FORCEINLINE_DEBUGGABLE const bool GetIsSPIRV(const FStaticShaderPlatform Platform)
	{
		check(IsValid(Platform));
		return Infos[Platform].bIsSPIRV;