bRequiresGeneratePrevTransformBuffer

bRequiresGeneratePrevTransformBuffer

#Overview

name: bRequiresGeneratePrevTransformBuffer

The value of this variable can be defined or overridden in .ini config files. 2 .ini config files referencing this setting variable.

It is referenced in 3 C++ source files.

#Summary

#Usage in the C++ source code

The purpose of bRequiresGeneratePrevTransformBuffer is to indicate whether a specific shader platform requires the generation of a previous transform buffer. This setting is related to the rendering system, specifically to shader and graphics processing capabilities.

This setting variable is primarily used within the RHI (Rendering Hardware Interface) module of Unreal Engine. It is part of the FGenericDataDrivenShaderPlatformInfo class, which is responsible for managing shader platform-specific information.

The value of this variable is set during the parsing of data-driven shader information. This occurs in the ParseDataDrivenShaderInfo function within the DataDrivenShaderPlatformInfo.cpp file.

This variable interacts with other shader platform-specific settings, such as bSupportsAnisotropicMaterials, bSupportsDualSourceBlending, and bRequiresRenderTargetDuringRaster. These settings collectively define the capabilities and requirements of a particular shader platform.

Developers must be aware that this setting is platform-specific and may affect performance and compatibility across different graphics hardware. It’s crucial to ensure that the correct value is set for each supported platform to avoid rendering issues or unnecessary overhead.

Best practices when using this variable include:

1. Thoroughly testing rendering performance and correctness on all target platforms when modifying this setting.
2. Consulting hardware specifications and graphics API documentation to determine the correct value for each platform.
3. Using the GetRequiresGeneratePrevTransformBuffer function to access this setting, rather than directly accessing the member variable.
4. Considering the implications of enabling this feature on memory usage and performance, especially on platforms with limited resources.
5. Documenting any platform-specific considerations or workarounds related to this setting for future reference.

#Setting Variables

#References In INI files

Location: <Workspace>/Engine/Config/VulkanPC/DataDrivenPlatformInfo.ini:101, section: [ShaderPlatform VULKAN_SM5]

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

Location: <Workspace>/Engine/Config/VulkanPC/DataDrivenPlatformInfo.ini:220, section: [ShaderPlatform VULKAN_SM6]

• INI Section: ShaderPlatform VULKAN_SM6
• Raw value: false
• 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:251

Scope (from outer to inner):

file
function     void FGenericDataDrivenShaderPlatformInfo::ParseDataDrivenShaderInfo

Source code excerpt:

	GET_SECTION_BOOL_HELPER(bSupportsAnisotropicMaterials);
	GET_SECTION_BOOL_HELPER(bSupportsDualSourceBlending);
	GET_SECTION_BOOL_HELPER(bRequiresGeneratePrevTransformBuffer);
	GET_SECTION_BOOL_HELPER(bRequiresRenderTargetDuringRaster);
	GET_SECTION_BOOL_HELPER(bRequiresDisableForwardLocalLights);
	GET_SECTION_BOOL_HELPER(bCompileSignalProcessingPipeline);
	GET_SECTION_BOOL_HELPER(bSupportsMeshShadersTier0);
	GET_SECTION_BOOL_HELPER(bSupportsMeshShadersTier1);
	GET_SECTION_BOOL_HELPER(bSupportsMeshShadersWithClipDistance);

#Loc: <Workspace>/Engine/Source/Runtime/RHI/Public/DataDrivenShaderPlatformInfo.h:75

Scope (from outer to inner):

file
class        class FGenericDataDrivenShaderPlatformInfo

Source code excerpt:

	uint32 bSupportsAnisotropicMaterials : 1;
	uint32 bSupportsDualSourceBlending : 1;
	uint32 bRequiresGeneratePrevTransformBuffer : 1;
	uint32 bRequiresRenderTargetDuringRaster : 1;
	uint32 bRequiresDisableForwardLocalLights : 1;
	uint32 bCompileSignalProcessingPipeline : 1;
	uint32 bSupportsMeshShadersTier0 : 1;
	uint32 bSupportsMeshShadersTier1 : 1;
	uint32 bSupportsMeshShadersWithClipDistance : 1;

#Loc: <Workspace>/Engine/Source/Runtime/RHI/Public/DataDrivenShaderPlatformInfo.h:533

Scope (from outer to inner):

file
class        class FGenericDataDrivenShaderPlatformInfo
function     static const bool GetRequiresGeneratePrevTransformBuffer

Source code excerpt:

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

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