Name Strings

SPV_EXT_shader_invocation_reorder

Contact

See Issues list in the Khronos SPIRV-Registry repository: https://github.com/KhronosGroup/SPIRV-Registry

Contributors

  • Ashwin Lele, NVIDIA

  • Eric Werness, NVIDIA

  • Daniel Koch, NVIDIA

  • Pankaj Mistry, NVIDIA

  • Aaron Hagan, AMD

  • Stu Smith, AMD

  • Sebastian Neubauer, AMD

  • Alan Baker, Google

  • Sven Woop, Intel

  • Ben Ashbaugh, Intel

  • Baldur Karlsson, Valve

  • Matthew Moulton, Samsung

  • Tim Kong, Samsung

  • Members of Vulkan Ray Tracing TSG

Status

  • Approved by the SPIR-V Working Group: 2025-09-03

  • Ratified by the Khronos Board: 2025-10-17

Version

Last Modified Date

2025-01-27

Revision

2

Dependencies

This extension is written against the Unified SPIR-V Specification, Version 1.6, Revision 1.

This extension requires SPIR-V 1.4.

This extension requires SPV_KHR_ray_tracing.

This extension requires SPV_EXT_physical_storage_buffer, SPV_KHR_physical_storage_buffer or SPIR-V 1.5.

This extension interacts with SPV_NV_ray_tracing_motion_blur.

This extension interacts with SPV_KHR_ray_tracing_position_fetch.

This extension interacts with SPV_KHR_ray_query.

Overview

This extension adds hit objects and reordering builtins to provide finer grain control over traversal during ray tracing.

Extension Name

To use this extension within a SPIR-V module, the following OpExtension must be present in the module:

OpExtension "SPV_EXT_shader_invocation_reorder"

New Capabilities

This extension introduces new capabilities:

ShaderInvocationReorderEXT

New Storage Classes

Storage classes added under the ShaderInvocationReorderEXT capability

HitObjectAttributeEXT

New Decorations

This extension introduces new decorations:

HitObjectShaderRecordBufferEXT

New Instructions

Instructions added under the ShaderInvocationReorderEXT capability

OpTypeHitObjectEXT
OpReorderThreadWithHintEXT
OpReorderThreadWithHitObjectEXT
OpHitObjectIsMissEXT
OpHitObjectIsHitEXT
OpHitObjectIsEmptyEXT
OpHitObjectGetRayTMinEXT
OpHitObjectGetRayTMaxEXT
OpHitObjectGetRayFlagsEXT
OpHitObjectGetObjectRayOriginEXT
OpHitObjectGetObjectRayDirectionEXT
OpHitObjectGetWorldRayOriginEXT
OpHitObjectGetWorldRayDirectionEXT
OpHitObjectGetObjectToWorldEXT
OpHitObjectGetWorldToObjectEXT
OpHitObjectGetIntersectionTriangleVertexPositionsEXT
OpHitObjectGetInstanceCustomIndexEXT
OpHitObjectGetInstanceIdEXT
OpHitObjectGetGeometryIndexEXT
OpHitObjectGetPrimitiveIndexEXT
OpHitObjectGetHitKindEXT
OpHitObjectGetAttributesEXT
OpHitObjectGetCurrentTimeEXT
OpHitObjectGetShaderBindingTableRecordIndexEXT
OpHitObjectSetShaderBindingTableRecordIndexEXT
OpHitObjectGetShaderRecordBufferHandleEXT
OpHitObjectExecuteShaderEXT
OpHitObjectRecordFromQueryEXT
OpHitObjectRecordMissEXT
OpHitObjectRecordMissMotionEXT
OpHitObjectRecordEmptyEXT
OpHitObjectTraceRayEXT
OpHitObjectTraceRayMotionEXT
OpHitObjectReorderExecuteShaderEXT
OpHitObjectTraceReorderExecuteEXT
OpHitObjectTraceMotionReorderExecuteEXT

Modifications to the SPIR-V Specification

(Modify Section 2.2.1, Instructions )

Add OpTraceRayWithHitObjectEXT, OpHitObjectExecuteShaderEXT, *OpHitObjectReorderExecuteShaderEXT, *OpHitObjectTraceReorderExecuteEXT to the list of shader call instructions.

(Add the following terminology to section 2.2.2, Types)

Hit object type: The type returned by OpTypeHitObjectEXT.

(Add to the list of opaque types in section 2.2.2, Types)

  • OpTypeHitObjectEXT

(Modify Section 3.2, Decorations, adding a row to the Decoration table)
Decoration Requires

5389

HitObjectShaderRecordBufferEXT
Apply to a variable to indicate that it represents a shader record buffer address obtained from a hit object. This decoration marks variables that store physical storage buffer pointers returned by OpHitObjectGetShaderRecordBufferHandleEXT.
Valid targets: OpVariable

ShaderInvocationReorderEXT
(Modify Section 3.7, Storage Class, adding rows to the Storage Class table)
Storage Class Enabling Capabilities Enabled by Extension

5411

HitObjectAttributeEXT
Used for storing attributes of geometry intersected by a ray to be passed on to hit object instructions. Visible across all functions in the current invocation. Not shared externally. Variables declared with this storage class can be both read and written to, but cannot have initializers. Only allowed in RayGenerationKHR, ClosestHitKHR, and MissKHR execution models.

ShaderInvocationReorderEXT

SPV_EXT_shader_invocation_reorder
(Modify Section 3.31, Capability, adding a row to the Capability table)
Capability Implicitly Declares

5388

ShaderInvocationReorderEXT

RayTracingKHR
(Add the following line to the description of OpTypePointer, in Section 3.32.6, Type-Declaration Instructions)

If Type is OpTypeHitObjectEXT, Storage Class must be Private or Function.

(Add the following line to the description of OpStore and OpLoad, in Section 3.32.8, Memory Instructions)

The Type operand to the OpTypePointer used for Pointer must not be OpTypeHitObjectEXT.

(Add the following line to the description of OpCopyMemory and OpCopyMemorySized, in Section 3.32.8, Memory Instructions)

The Type operand to the OpTypePointer used for Target or Source must not be OpTypeHitObjectEXT.

(Modify Section 2.16.1, Universal Validation Rules)

Add the following instructions to the list of instructions that may have a pointer as an operand:

  • OpReorderThreadWithHitObjectEXT

  • OpHitObjectTraceRayEXT

  • OpHitObjectTraceRayMotionEXT

  • OpHitObjectRecordFromQueryEXT

  • OpHitObjectRecordMissEXT

  • OpHitObjectRecordMissMotionEXT

  • OpHitObjectRecordEmptyEXT

  • OpHitObjectExecuteShaderEXT

  • OpHitObjectGetCurrentTimeEXT

  • OpHitObjectGetAttributesEXT

  • OpHitObjectGetHitKindEXT

  • OpHitObjectGetPrimitiveIndexEXT

  • OpHitObjectGetGeometryIndexEXT

  • OpHitObjectGetInstanceIdEXT

  • OpHitObjectGetInstanceCustomIndexEXT

  • OpHitObjectGetObjectRayOriginEXT

  • OpHitObjectGetObjectRayDirectionEXT

  • OpHitObjectGetWorldRayDirectionEXT

  • OpHitObjectGetWorldRayOriginEXT

  • OpHitObjectGetObjectToWorldEXT

  • OpHitObjectGetWorldToObjectEXT

  • OpHitObjectGetIntersectionTriangleVertexPositionsEXT

  • OpHitObjectGetRayTMaxEXT

  • OpHitObjectGetRayTMinEXT

  • OpHitObjectGetRayFlagsEXT

  • OpHitObjectGetShaderBindingTableRecordIndexEXT

  • OpHitObjectSetShaderBindingTableRecordIndexEXT

  • OpHitObjectGetShaderRecordBufferHandleEXT

  • OpHitObjectIsEmptyEXT

  • OpHitObjectIsHitEXT

  • OpHitObjectIsMissEXT

  • OpHitObjectReorderExecuteShaderEXT

  • OpHitObjectTraceReorderExecuteEXT

  • OpHitObjectTraceMotionReorderExecuteEXT

(Add a new sub section 3.36.Reorder Instructions)

For reorder instructions providing a hint, the hint value used for reordering is the specified number of bits from the LSBs of the hint value interpreted as an unsigned integer. The higher bits of that hint value are higher priority than the lower bits. If both the hint and the hit object are provided, the implementation should prioritize the hint bits lower in the reorder priority than the shader referenced by the hit object but higher than any other information in the hit object.

OpReorderThreadWithHintEXT

Reorder threads based on user provided hint. Similar Hint values indicate similarity of subsequent work done after this call. Behavior is described above.

Hint must be a 32-bit integer-type scalar.

Bits must be a 32-bit integer-type scalar.

This instruction is allowed only in RayGenerationKHR execution models.

Capability:
ShaderInvocationReorderEXT

3

5314

<id> Hint

<id> Bits

OpReorderThreadWithHitObjectEXT

Reorder threads based on hit object supplemented by Hint and Bits if they are optionally provided values. Behavior is described above.

Hit Object must be a pointer to hit object used to reorder threads.

Hint must be a 32-bit integer-type scalar.

Bits must be a 32-bit integer-type scalar.

Hint and Bits are optional together i.e Either both Hint and Bits should be provided or neither.

This instruction is allowed only in RayGenerationKHR execution models.

Capability:
ShaderInvocationReorderEXT

2 + variable

5315

<id> Hit Object

Optional <id> Hint

Optional <id> Bits
(Add a new sub section 3.36.Hit Object Instructions)

The semantics of the arguments of OpHitObjectTraceRayEXT and OpHitObjectTraceRayMotionEXT are same as those with the same names of OpTraceRayKHR and OpTraceRayMotionNV as defined in the SPV_KHR_ray_tracing and SPV_NV_ray_tracing_motion_blur extensions, respectively. The sequence OpHitObjectTraceRayEXT, OpReorderThreadWithHitObjectEXT, OpHitObjectExecuteShaderEXT is equivalent to OpTraceRayKHR instruction.

OpHitObjectTraceRayEXT

Traces a ray and triggers execution on any-hit or intersection shaders and populates resulting hit or miss information in the hit object.

Hit Object is a pointer to the hit object.

Acceleration Structure is the descriptor for the acceleration structure to trace into.

Ray Flags contains one or more of the ray flag values. Refer to the client API specification for details.
Cull Mask is the mask to test against the instance mask.

SBT Offset and SBT Stride control indexing into the SBT for hit shaders called from this trace. SBT stands for Shader Binding Table. Refer to the client API specification for details.

Miss Index is the index of the miss shader to be called from this trace call.

Ray Origin, Ray Tmin, Ray Direction, and Ray Tmax control the basic parameters of the ray to be traced.

Payload is a pointer to the ray payload structure to use for this trace. Payload must be the result of an OpVariable with a storage class of RayPayloadKHR or IncomingRayPayloadKHR.

Ray Flags, Cull Mask, SBT Offset, SBT Stride, and Miss Index must be a 32-bit integer type scalar.

Only the 8 least-significant bits of Cull Mask are used by this instruction - other bits are ignored.
Only the 4 least-significant bits of SBT Offset and SBT Stride are used by this instruction - other bits are ignored.
Only the 16 least-significant bits of Miss Index are used by this instruction - other bits are ignored.
Ray Origin and Ray Direction must be a 32-bit float type 3-component vector.

Ray Tmin and Ray Tmax must be a 32-bit float type scalar.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

This instruction is a shader call instruction which may invoke shaders with the IntersectionKHR and AnyHitKHR execution models.

Capability:
ShaderInvocationReorderEXT

13

5316

<id> Hit Object

<id> Acceleration Structure

<id> Ray Flags

<id> Cull Mask

<id> SBT Offset

<id> SBT Stride

<id> Miss Index

<id> Ray Origin

<id> Ray Tmin

<id> Ray Direction

<id> Ray Tmax

<id> Payload

OpHitObjectTraceRayMotionEXT

Traces a ray and triggers execution of any-hit or intersection shaders and populates resulting hit or miss information in the hit object.

Hit Object is a pointer to the hit object.

Acceleration Structure is the descriptor for the acceleration structure to trace into.

Ray Flags contains one or more of the ray flag values. Refer to the client API specification for details.
Cull Mask is the mask to test against the instance mask.

SBT Offset and SBT Stride control indexing into the SBT for hit shaders called from this trace. SBT stands for Shader Binding Table. Refer to the client API specification for details.

Miss Index is the index of the miss shader to be called from this trace call.

Ray Origin, Ray Tmin, Ray Direction, and Ray Tmax control the basic parameters of the ray to be traced.

Payload is a pointer to the ray payload structure to use for this trace. Payload must be the result of an OpVariable with a storage class of RayPayloadKHR or IncomingRayPayloadKHR.

Ray Flags, Cull Mask, SBT Offset, SBT Stride, and Miss Index must be a 32-bit integer type scalar.

Only the 8 least-significant bits of Cull Mask are used by this instruction - other bits are ignored.
Only the 4 least-significant bits of SBT Offset and SBT Stride are used by this instruction - other bits are ignored.
Only the 16 least-significant bits of Miss Index are used by this instruction - other bits are ignored.
Ray Origin and Ray Direction must be a 32-bit float type 3-component vector.

Ray Tmin and Ray Tmax must be a 32-bit float type scalar.

Current Time must be a 32-bit float type scalar.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models with SPV_NV_ray_tracing_motion_blur extension.

This instruction is a shader call instruction which may invoke shaders with the IntersectionKHR and AnyHitKHR execution models.

Capability:
ShaderInvocationReorderEXT, RayTracingMotionBlurNV

14

5317

<id> Hit Object

<id> Acceleration Structure

<id> Ray Flags

<id> Cull Mask

<id> SBT Offset

<id> SBT Stride

<id> Miss Index

<id> Ray Origin

<id> Ray Tmin

<id> Ray Direction

<id> Ray Tmax

<id> Current Time

<id> Payload

OpHitObjectRecordFromQueryEXT

Populates the hit object to represent a hit without tracing a ray.

Hit Object is a pointer to the hit object.

Ray Query is a pointer to the ray query pull hit information from.

SBT Record Index controls indexing into the SBT to determine the closest-hit shader to be encoded in the hit object. SBT stands for Shader Binding Table. Refer to the client API specification for details.

SBT Record Index must be a 32 bit integer type scalar.
Hit Object Attributes contains the attributes of the hit which are to be encoded in Hit Object. This must be an OpVariable in HitObjectAttributeEXT storage class.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

5

5304

<id> Hit Object

<id> Ray Query

<id> SBT Record Index

<id> Hit Object Attributes

OpHitObjectRecordMissEXT

Encodes the hit object to represent a miss without tracing a ray.

Hit Object is a pointer to the hit object.

Ray Flags contains one or more of the ray flag values. Refer to the client API specification for details.
Miss Index is the index of the miss shader to be encoded in the hit object.

Miss Index must be a 32-bit unsigned integer type scalar.
Ray Origin, Ray Tmin, Ray Direction, and Ray Tmax control the basic parameters of the ray.

Ray Origin and Ray Direction must be a 32-bit float type 3-component vector.

Ray Tmin and Ray Tmax must be a 32-bit float type scalar.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

8

5305

<id> Hit Object

<id> Ray Flags

<id> Miss Index

<id> Ray Origin

<id> Ray TMin

<id> Ray Direction

<id> Ray TMax

OpHitObjectRecordMissMotionEXT

Encodes the hit object to represent a miss without tracing a ray.

Hit Object is a pointer to the hit object.

Ray Flags contains one or more of the ray flag values. Refer to the client API specification for details.
Miss Index is the index of the miss shader to be encoded in the hit object.

Miss Index must be a 32-bit unsigned integer type scalar.
Ray Origin, Ray Tmin, Ray Direction, and Ray Tmax control the basic parameters of the ray.

Ray Origin and Ray Direction must be a 32-bit float type 3-component vector.

Ray Tmin and Ray Tmax must be a 32-bit float type scalar.

Current Time must be a 32-bit float type scalar.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models with SPV_NV_ray_tracing_motion_blur extension.

Capability:
ShaderInvocationReorderEXT, RayTracingMotionBlurNV

9

5306

<id> Hit Object

<id> Ray Flags

<id> Miss Index

<id> Ray Origin

<id> Ray TMin

<id> Ray Direction

<id> Ray TMax

<id> Current Time

OpHitObjectRecordEmptyEXT

Encodes the hit object to represent an empty hit object which is neither a hit nor a miss.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

2

5318

<id> Hit Object

OpHitObjectExecuteShaderEXT

Executes the closest-hit or miss shader as encoded in the hit object.
If the hit object encodes an empty hit object or was created from a ray query with no shader index set, no function is called.

Hit Object is a pointer to the hit object.

Payload is a pointer to the ray payload structure to use for this trace. Payload must be the result of an OpVariable with a storage class of RayPayloadKHR or IncomingRayPayloadKHR.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

This instruction is a shader call instruction which may invoke shaders with the ClosestHitKHR, and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

3

5319

<id> Hit Object

<id> Payload

OpHitObjectGetCurrentTimeEXT

Returns the current time value encoded in the hit object.

Result is the current time value as encoded in the hit object.

Result Type must be a 32-bit floating-point type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5320

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetAttributesEXT

Returns the attributes as encoded in the hit object.

Hit Object is a pointer to the hit object.

Hit Object Attributes contains the attributes of the hit which are to be encoded in Hit Object. This must be an OpVariable in HitObjectAttributeEXT storage class.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

3

5321

<id> Hit Object

<id> Hit Object Attributes

OpHitObjectGetHitKindEXT

Returns a unsigned integer value of the hit as encoded in the hit object with front face or back face of a primitive.

Result is 0xFE if hit encoded in the hit object is with front facing primitive else is 0xFF if it is back facing primitive.

Result Type must be a 32bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5322

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetPrimitiveIndexEXT

Returns the primitive index as encoded in the hit object.

Result is the primitive index as encoded in the hit object.

Result Type must be a 32-bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5323

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetGeometryIndexEXT

Returns the geometry index as encoded in the hit object.

Result is the geometry index as encoded in the hit object.

Result Type must be a 32-bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5324

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetInstanceIdEXT

Returns the instance id as encoded in the hit object.

Result is the instance id as encoded in the hit object.

Result Type must be a 32-bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5325

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetInstanceCustomIndexEXT

Returns the application specified custom index value as encoded in the hit object.

Result is the application specified custom index value as encoded in the hit object.

Result Type must be a 32-bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5326

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetObjectRayOriginEXT

Returns the object-space ray origin as encoded in the hit object.

Result is the ray object-space ray origin as encoded in the hit object.

Result Type must be a 32-bit floating-point type 3-component vector.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5327

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetObjectRayDirectionEXT

Returns the object-space ray direction as encoded in the hit object.

Result is the ray object-space ray direction as encoded in the hit object.

Result Type must be a 32-bit floating-point type 3-component vector.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5328

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetWorldRayDirectionEXT

Returns the world-space ray direction as encoded in the hit object.

Result is the ray world-space ray direction as encoded in the hit object.

Result Type must be a 32-bit floating-point type 3-component vector.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5329

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetWorldRayOriginEXT

Returns the world-space ray origin as encoded in the hit object.

Result is the ray world-space ray origin as encoded in the hit object.

Result Type must be a 32-bit floating-point type 3-component vector.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5330

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetObjectToWorldEXT

Returns a matrix that transforms values from object-space to world-space as encoded in the hit object.

Result is the matrix.

Result Type must be a matrix with a Column Count of 4, and a Column Type that is a vector type with a Component Type that is a 32-bit floating-point type and a Component Count of 3.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5331

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetWorldToObjectEXT

Returns a matrix that transforms values from world-space to object-space as encoded in the hit object.

Result is the matrix.

Result Type must be a matrix with a Column Count of 4, and a Column Type that is a vector type with a Component Type that is a 32-bit floating-point type and a Component Count of 3.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5332

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetIntersectionTriangleVertexPositionsEXT

Gets the vertex positions for the triangle encoded in the hit object.

Result is the returned vertex positions.

Result Type must be an array with a Length of 3, and an Element Type that is a vector type with a Component Type that is a 32-bit floating-point type and a Component Count of 3.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5307

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetRayTMaxEXT

Returns the Ray Tmax value encoded in the hit object.
Semantics are similar to RayTMaxKHR builtin as defined in SPV_KHR_ray_tracing.
Result is the Ray Tmax value as encoded in the hit object.

Result Type must be a 32-bit floating-point type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5333

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetRayTMinEXT

Returns the Ray Tmin value encoded in the hit object.
Semantics are similar to RayTMinKHR builtin as defined in SPV_KHR_ray_tracing.
Result is the Ray Tmin value as encoded in the hit object.

Result Type must be a 32-bit floating-point type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5347

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetRayFlagsEXT

Returns the Ray Flags value encoded in the hit object.
Semantics are similar to RayFlagsKHR builtin as defined in SPV_KHR_ray_tracing.
Result is the Ray Flags value as encoded in the hit object.

Result Type must be a 32-bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5308

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetShaderBindingTableRecordIndexEXT

Returns the index for the record in shader binding table as encoded in hit object.

Result is the current SBT index value as encoded in the hit object.

Result Type must be a 32-bit integer type scalar.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5348

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectSetShaderBindingTableRecordIndexEXT

Sets the index for the record in shader binding table as encoded in hit object.

Hit Object is a pointer to the hit object.

SBT Record Index is the new SBT index value to be encoded in the hit object.

SBT Record Index must be a 32-bit integer type scalar.
This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

3

5309

<id> Hit Object

<id> SBT Record Index

OpHitObjectGetShaderRecordBufferHandleEXT

Returns the address of shader record buffer for the hit or miss record encoded in hit object.

Result is the address of data in shader record as encoded in the hit object.

Result Type must be a 32-bit integer type 2-component vector.

Hit Object is a pointer to the hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5349

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectIsEmptyEXT

Returns a boolean indicating whether the hit object is an empty hit object.

Result is true if hit object encodes a NOP, false otherwise.

Result Type must be a boolean type scalar.

Hit Object must be a pointer to hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5350

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectIsHitEXT

Returns a boolean indicating whether the hit object has encoded a hit.

Result is true if hit object encodes a hit, false otherwise.

Result Type must be a boolean type scalar.

Hit Object must be a pointer to hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

4

5351

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectIsMissEXT

Returns a boolean indicating whether the hit object has encoded a miss.

Result is true if hit object encodes a miss, false otherwise.

Result Type must be a boolean type scalar.

Hit Object must be a pointer to hit object.

This instruction is allowed only in RayGenerationKHR, ClosestHitKHR and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

3

5352

<id> Result Type

<id> Result

<id> Hit Object
(Add a new sub section 3.36.Fused Hit Object Instructions)

OpHitObjectReorderExecuteShaderEXT

Reorder threads based on hit object supplemented by Hint and Bits if they are optionally provided values followed by executing the shader. Behavior is as described in Reorder Instructions above.

Hit Object must be a pointer to hit object used to reorder threads.

Payload is a pointer to the ray payload structure to use for this trace. Payload must be the result of an OpVariable with a storage class of RayPayloadKHR or IncomingRayPayloadKHR.

Hint must be a 32-bit integer-type scalar.

Bits must be a 32-bit integer-type scalar.

Hint and Bits are optional together i.e Either both Hint and Bits should be provided or neither.

This instruction is allowed only in RayGenerationKHR execution models.

This instruction is a shader call instruction which may invoke shaders with the ClosestHitKHR, and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

2 + variable

5310

<id> Hit Object

<id> Payload

Optional <id> Hint

Optional <id> Bits

OpHitObjectTraceReorderExecuteEXT

Traces a ray and triggers execution on any-hit or intersection shaders and populates resulting hit or miss information in the hit object.

Hit Object is a pointer to the hit object.

Acceleration Structure is the descriptor for the acceleration structure to trace into.

Ray Flags contains one or more of the ray flag values. Refer to the client API specification for details.
Cull Mask is the mask to test against the instance mask.

SBT Offset and SBT Stride control indexing into the SBT for hit shaders called from this trace. SBT stands for Shader Binding Table. Refer to the client API specification for details.

Miss Index is the index of the miss shader to be called from this trace call.

Ray Origin, Ray Tmin, Ray Direction, and Ray Tmax control the basic parameters of the ray to be traced.

Payload is a pointer to the ray payload structure to use for this trace. Payload must be the result of an OpVariable with a storage class of RayPayloadKHR or IncomingRayPayloadKHR.

Ray Flags, Cull Mask, SBT Offset, SBT Stride, and Miss Index must be a 32-bit integer type scalar.

Only the 8 least-significant bits of Cull Mask are used by this instruction - other bits are ignored.
Only the 4 least-significant bits of SBT Offset and SBT Stride are used by this instruction - other bits are ignored.
Only the 16 least-significant bits of Miss Index are used by this instruction - other bits are ignored.
Ray Origin and Ray Direction must be a 32-bit float type 3-component vector.

Ray Tmin and Ray Tmax must be a 32-bit float type scalar.

Hint must be a 32-bit integer-type scalar.

Bits must be a 32-bit integer-type scalar.

Hint and Bits are optional together i.e Either both Hint and Bits should be provided or neither.

This instruction is allowed only in RayGenerationKHR execution models.

This instruction is a shader call instruction which may invoke shaders with the IntersectionKHR, AnyHitKHR, ClosestHitKHR, and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT

13 + variable

5311

<id> Hit Object

<id> Acceleration Structure

<id> Ray Flags

<id> Cull Mask

<id> SBT Offset

<id> SBT Stride

<id> Miss Index

<id> Ray Origin

<id> Ray Tmin

<id> Ray Direction

<id> Ray Tmax

<id> Payload

Optional <id> Hint

Optional <id> Bits

OpHitObjectTraceMotionReorderExecuteEXT

Traces a ray and triggers execution of any-hit or intersection shaders and populates resulting hit or miss information in the hit object.

Hit Object is a pointer to the hit object.

Acceleration Structure is the descriptor for the acceleration structure to trace into.

Ray Flags contains one or more of the ray flag values. Refer to the client API specification for details.
Cull Mask is the mask to test against the instance mask.

SBT Offset and SBT Stride control indexing into the SBT for hit shaders called from this trace. SBT stands for Shader Binding Table. Refer to the client API specification for details.

Miss Index is the index of the miss shader to be called from this trace call.

Ray Origin, Ray Tmin, Ray Direction, and Ray Tmax control the basic parameters of the ray to be traced.

Payload is a pointer to the ray payload structure to use for this trace. Payload must be the result of an OpVariable with a storage class of RayPayloadKHR or IncomingRayPayloadKHR.

Ray Flags, Cull Mask, SBT Offset, SBT Stride, and Miss Index must be a 32-bit integer type scalar.

Only the 8 least-significant bits of Cull Mask are used by this instruction - other bits are ignored.
Only the 4 least-significant bits of SBT Offset and SBT Stride are used by this instruction - other bits are ignored.
Only the 16 least-significant bits of Miss Index are used by this instruction - other bits are ignored.
Ray Origin and Ray Direction must be a 32-bit float type 3-component vector.

Ray Tmin and Ray Tmax must be a 32-bit float type scalar.

Current Time must be a 32-bit float type scalar.

Hint must be a 32-bit integer-type scalar.

Bits must be a 32-bit integer-type scalar.

Hint and Bits are optional together i.e Either both Hint and Bits should be provided or neither.

This instruction is allowed only in RayGenerationKHR execution models with SPV_NV_ray_tracing_motion_blur extension.

This instruction is a shader call instruction which may invoke shaders with the IntersectionKHR, AnyHitKHR, ClosestHitKHR, and MissKHR execution models.

Capability:
ShaderInvocationReorderEXT, RayTracingMotionBlurNV

14 + variable

5312

<id> Hit Object

<id> Acceleration Structure

<id> Ray Flags

<id> Cull Mask

<id> SBT Offset

<id> SBT Stride

<id> Miss Index

<id> Ray Origin

<id> Ray Tmin

<id> Ray Direction

<id> Ray Tmax

<id> Current Time

<id> Payload

Optional <id> Hint

Optional <id> Bits
(Modify Section 3.36.6, Type-Declaration Instructions, adding a new table)

OpTypeHitObjectEXT

Declares a hit object type which is an opaque object representing state during ray tracing traversal.

This type is opaque: values of this type have no defined physical size or bit pattern.

Capability:
ShaderInvocationReorderEXT

2

5313

<id> Result

Validation Rules

An OpExtension must be added to the SPIR-V for validation layers to check legal use of this extension:

OpExtension "SPV_EXT_shader_invocation_reorder"

Interactions with SPV_NV_ray_tracing_motion_blur

If the SPV_NV_ray_tracing_motion_blur extension is not supported, the OpHitObjectTraceRayMotionEXT, OpHitObjectRecordMissMotionEXT, and OpHitObjectTraceMotionReorderExecuteEXT instructions are not supported.

Interactions with SPV_KHR_ray_tracing_position_fetch

If the SPV_KHR_ray_tracing_position_fetch extension is not supported the OpHitObjectGetIntersectionTriangleVertexPositionsEXT instruction is not supported.

Interactions with SPV_KHR_ray_query

If the SPV_KHR_ray_query extension is not supported the OpHitObjectRecordFromQueryEXT instruction is not supported.

Issues

None

Revision History

Rev Date Author Changes

1

2024-05-08

Eric Werness

Port to EXT

2

2025-01-27

Ashwin Lele

Renumber enums