Name Strings

SPV_NV_linear_swept_spheres

Contact

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

Contributors

  • Ashwin Lele, NVIDIA

  • Eric Werness, NVIDIA

  • Vikram Kushwaha, NVIDIA

Status

  • Complete

Version

Last Modified Date

2025-01-01

Revision

1

Dependencies

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

This extension requires SPIR-V 1.4.

This extension interacts with SPV_KHR_ray_tracing.

This extension interacts with SPV_KHR_ray_query.

This extension interacts with SPV_NV_shader_invocation_reorder.

Overview

This extension adds new functionality to support the Vulkan VK_NV_ray_tracing_linear_swept_spheres extension in SPIR-V.

Extension Name

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

OpExtension "SPV_NV_linear_swept_spheres"

New Capabilities

This extension introduces new capabilities:

RayTracingSpheresGeometryNV
RayTracingLinearSweptSpheresGeometryNV

New Builtins

Builtins added under the RayTracingLinearSweptSpheresGeometryNV capability

HitIsLSSNV
HitLSSPositionsNV
HitLSSRadiiNV

Builtins added under the RayTracingSpheresGeometryNV capability

HitIsSphereNV
HitSpherePositionNV
HitSphereRadiusNV

New Instructions

Instructions added under the RayTracingSpheresGeometryNV capability

OpHitObjectGetSpherePositionNV
OpHitObjectGetSphereRadiusNV
OpHitObjectIsSphereHitNV
OpRayQueryGetIntersectionSpherePositionNV
OpRayQueryGetIntersectionSphereRadiusNV
OpRayQueryIsSphereHitNV

Instructions added under the RayTracingLinearSweptSpheresGeometryNV capability

OpHitObjectGetLSSPositionsNV
OpHitObjectGetLSSRadiiNV
OpHitObjectIsLSSHitNV
OpRayQueryGetIntersectionLSSPositionsNV
OpRayQueryGetIntersectionLSSRadiiNV
OpRayQueryGetIntersectionLSSHitValueNV
OpRayQueryIsLSSHitNV

Modifications to the SPIR-V Specification

(Modify Section 3.21, Builtin, adding rows to the Builtin table)
Decoration Enabling Capabilities

5359

HitIsSphereNV
Indicates if current ray hit a sphere primitive. OpConstantTrue if hit is with a sphere primitive , OpConstantFalse otherwise.
Allowed in AnyHitKHR and ClosestHitKHR ray tracing execution models.

RayTracingSpheresGeometryNV

5360

HitIsLSSNV
Indicates if current ray hit a LSS primitive, OpConstantTrue if hit is with a LSS primitive , OpConstantFalse otherwise.
Allowed in AnyHitKHR and ClosestHitKHR ray tracing execution models.

RayTracingLinearSweptSpheresGeometryNV

5361

HitSpherePositionNV
The position of sphere primitive intersected by current ray.
Allowed in AnyHitKHR and ClosestHitKHR ray tracing execution models.

RayTracingSpheresGeometryNV

5396

HitLSSPositionsNV
The positions of two endcaps of LSS primitive intersected by current ray.
Allowed in AnyHitKHR and ClosestHitKHR ray tracing execution models.

RayTracingLinearSweptSpheresGeometryNV

5420

HitSphereRadiusNV
The radius of sphere primitive intersected by current ray.
Allowed in AnyHitKHR and ClosestHitKHR ray tracing execution models.

RayTracingSpheresGeometryNV

5421

HitLSSRadiiNV
The radii of two endcaps of LSS primitive intersected by current ray.
Allowed in AnyHitKHR and ClosestHitKHR ray tracing execution models.

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

5418

RayTracingSpheresGeometryNV

5419

RayTracingLinearSweptSpheresGeometryNV
(Modify sub-section 3.RF, Ray Flags, add a new row)

3.RF, Ray Flags

Ray Flags Enabling Capabilities

256

SkipBuiltinPrimitivesNV
Alias for SkipTrianglesKHR. See the Ray Primitive Culling section in the Vulkan API specification.

RayTracingSpheresGeometryNV or RayTracingLinearSweptSpheresGeometryNV
(Add a new sub section 3.36.Hit Object Instructions)

OpHitObjectGetSpherePositionNV

Returns object space position of sphere primitive as encoded in the hit object.

Result is object space position of sphere primitive.

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:
RayTracingSpheresGeometryNV

4

5432

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetSphereRadiusNV

Returns sphere radius of sphere primitive as encoded in the hit object.

Result is radius of sphere primitive.

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:
RayTracingSpheresGeometryNV

4

5433

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetLSSPositionsNV

Returns object space positions of endcaps of LSS primitive as encoded in the hit object.

Result is object space positions of LSS primitive.

Result Type must be an array with a Length of 2, 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:
RayTracingLinearSweptSpheresGeometryNV

4

5434

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectGetLSSRadiiNV

Returns radii of endcaps of LSS primitive as encoded in the hit object.

Result is radii of endcaps of LSS primitive.

Result Type must be an array with a Length of 2, and an Element Type that is 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:
RayTracingLinearSweptSpheresGeometryNV

4

5435

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectIsSphereHitNV

Returns a boolean indicating if hit is with sphere primitive as encoded in the hit object.

Result is true if hit is with sphere primitive, false otherwise.

Result Type must be a boolean type scalar.

Hit Object is a pointer to the hit object.

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

Capability:
RayTracingSpheresGeometryNV

4

5436

<id> Result Type

<id> Result

<id> Hit Object

OpHitObjectIsLSSHitNV

Returns a boolean indicating if hit is with LSS primitive as encoded in the hit object.

Result is true if hit is with LSS primitive, false otherwise.

Result Type must be a boolean type scalar.

Hit Object is a pointer to the hit object.

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

Capability:
RayTracingLinearSweptSpheresGeometryNV

4

5437

<id> Result Type

<id> Result

<id> Hit Object
(Add a new sub section 3.36.RQInstructions, Ray Query Instructions)

OpRayQueryGetIntersectionSpherePositionNV

Returns the object space position of sphere primitive at the current intersection.

Result is the returned sphere position.

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

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingSpheresGeometryNV

5

5427

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

OpRayQueryGetIntersectionSphereRadiusNV

Returns the radius of the sphere primitive at the current intersection.

Result is the returned sphere radius.

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

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingSpheresGeometryNV

5

5428

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

OpRayQueryGetIntersectionLSSPositionsNV

Returns the positions of encaps of the LSS primitive at the current intersection.

Result is the returned LSS primitive endcap positions.

Result Type must be an array with a Length of 2, 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.

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingLinearSweptSpheresGeometryNV

5

5429

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

OpRayQueryGetIntersectionLSSRadiiNV

Returns the radii of endcaps of the LSS primitive at the current intersection.

Result is the returned LSS primitive endcap radii.

Result Type must be an array with a Length of 2, and an Element Type that is a 32-bit floating-point type scalar.

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingLinearSweptSpheresGeometryNV

5

5430

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

OpRayQueryGetIntersectionLSSHitValueNV

Returns the floating point parametric value at hit for LSS primitive at the current intersection.

Result is the returned floating point value.
Result Type must be a 32-bit floating-point type scalar.

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingLinearSweptSpheresGeometryNV

5

5431

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

OpRayQueryIsSphereHitNV

Returns a boolean indicating hit with a sphere primitive at the current intersection.

Result is the true if hit is with sphere primitive, false otherwise

Result Type must be a boolean type scalar.

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingSpheresGeometryNV

5

5438

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

OpRayQueryIsLSSHitNV

Returns a boolean indicating hit with a LSS primitive at the current intersection.

Result is the true if hit is with LSS primitive, false otherwise.

Result Type must be a boolean type scalar.

Intersection must be the <id> of a constant instruction with a 32-bit scalar integer type.

Intersection identifies which intersection values should be returned for, either the current candidate or the closest recorded hit so far; see Ray Query Intersection.

Ray Query is a pointer to the ray query object.

If Intersection is RayQueryCandidateIntersectionKHR, behavior is undefined if OpRayQueryProceedKHR was not executed on the same ray query object, or if the last value returned by such an execution of OpRayQueryProceedKHR was not true.

If Intersection is RayQueryCommittedIntersectionKHR, behavior is undefined if there is no current committed intersection (see OpRayQueryCommittedTypeKHR).

Capability:
RayTracingLinearSweptSpheresGeometryNV

5

5439

<id> Result Type

<id> Result

<id> Ray Query

<id> Intersection

Validation Rules

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

OpExtension "SPV_NV_linear_swept_spheres"

Interactions with SPV_KHR_ray_tracing

Builtins HitIsSphereNV, HitIsLSSNV, HitSpherePositionNV HitSphereRadiusNV, HitLSSPositionsNV, HitLSSRadiiNV are supported only if SPV_KHR_ray_tracing is supported.

Interactions with SPV_KHR_ray_query

OpRayQueryGetIntersectionSpherePositionNV, OpRayQueryGetIntersectionSphereRadiusNV, OpRayQueryGetIntersectionLSSPositionsNV, OpRayQueryGetIntersectionLSSRadiiNV, OpRayQueryGetIntersectionLSSHitValueNV,OpRayQueryIsSphereHitNV, OpRayQueryIsLSSHitNV are supported only if SPV_KHR_ray_query is supported.

Interactions with SPV_NV_shader_invocation_reorder

OpHitObjectGetSpherePositionNV, OpHitObjectGetSphereRadiusNV,OpHitObjectGetLSSPositionsNV, OpHitObjectGetLSSRadiiNV, OpHitObjectIsSphereHitNV, OpHitObjectIsLSSHitNV are supported only if SPV_NV_shader_invocation_reorder is supported.

Issues

None

Revision History

Rev Date Author Changes

1

2025-01-01

Ashwin Lele

Internal revisions.