D3D12DDI_HIT_GROUP_DESC_0054 structure (d3d12umddi.h)

Describes a hit group.

Syntax

typedef struct D3D12DDI_HIT_GROUP_DESC_0054 {
  LPCWSTR                       HitGroupExport;
  D3D12DDI_HIT_GROUP_TYPE       Type;
  LPCWSTR                       AnyHitShaderImport;
  LPCWSTR                       ClosestHitShaderImport;
  LPCWSTR                       IntersectionShaderImport;
  D3D12DDI_EXPORT_SUMMARY_FLAGS SummaryFlags;
} D3D12DDI_HIT_GROUP_DESC_0054;

Members

HitGroupExport

Name of the hit group.

Type

A D3D12DDI_HIT_GROUP_TYPE enumeration that represents the type of hit group.

AnyHitShaderImport

The any hit shader import.

ClosestHitShaderImport

Closest hit shader import.

IntersectionShaderImport

Intersection shader import.

SummaryFlags

A D3D12DDI_EXPORT_SUMMARY_FLAGS flag that indicates the properties the runtime has determined about the shader export.

Remarks

A hit group is one or more shaders that consists of:

• 0 or 1 intersection shader
• 0 or 1 any hit shader
• 0 or 1 closest hit shader

Individual geometries in a given instance each refer to a hit group to provide their shader code. The point of the grouping is to allow implementations to be able to compile and execute the group as efficiently as rays interacting with geometry

Ray generation shaders and miss shaders aren’t part of hit groups because they aren’t involved directly with geometry.

If a hit group contains an intersection shader, it can only be used with procedural primitive geometry. If a hit group does not contain an intersection shader, it can only be used with triangle geometry.

A hit group with no shaders at all is also possible, by simply using NULL as it’s shader identifier.

An empty hit group can be useful, for example, if the app doesn’t want to do anything for hits and only cares about the miss shader running when nothing has been hit.

Requirements

Requirement	Value
Minimum supported client	Windows 10, version 1809
Header	d3d12umddi.h