Package org.lwjgl.vulkan

Class EXTShaderSubgroupBallot

  • public final class EXTShaderSubgroupBallot
extends java.lang.Object
    This extension adds support for the following SPIR-V extension in Vulkan:
    • SPV_KHR_shader_ballot

    This extension provides the ability for a group of invocations, which execute in parallel, to do limited forms of cross-invocation communication via a group broadcast of a invocation value, or broadcast of a bitarray representing a predicate value from each invocation in the group.

    This extension provides access to a number of additional built-in shader variables in Vulkan:

    • SubgroupEqMaskKHR, containing the subgroup mask of the current subgroup invocation,
    • SubgroupGeMaskKHR, containing the subgroup mask of the invocations greater than or equal to the current invocation,
    • SubgroupGtMaskKHR, containing the subgroup mask of the invocations greater than the current invocation,
    • SubgroupLeMaskKHR, containing the subgroup mask of the invocations less than or equal to the current invocation,
    • SubgroupLtMaskKHR, containing the subgroup mask of the invocations less than the current invocation,
    • SubgroupLocalInvocationId, containing the index of an invocation within a subgroup, and
    • SubgroupSize, containing the maximum number of invocations in a subgroup.

    Additionally, this extension provides access to the new SPIR-V instructions:

    • OpSubgroupBallotKHR,
    • OpSubgroupFirstInvocationKHR, and
    • OpSubgroupReadInvocationKHR,

    When using GLSL source-based shader languages, the following variables and shader functions from GL_ARB_shader_ballot can map to these SPIR-V built-in decorations and instructions:

    • in uint64_t gl_SubGroupEqMaskARB; → SubgroupEqMaskKHR,
    • in uint64_t gl_SubGroupGeMaskARB; → SubgroupGeMaskKHR,
    • in uint64_t gl_SubGroupGtMaskARB; → SubgroupGtMaskKHR,
    • in uint64_t gl_SubGroupLeMaskARB; → SubgroupLeMaskKHR,
    • in uint64_t gl_SubGroupLtMaskARB; → SubgroupLtMaskKHR,
    • in uint gl_SubGroupInvocationARB; → SubgroupLocalInvocationId,
    • uniform uint gl_SubGroupSizeARB; → SubgroupSize,
    • ballotARB() → OpSubgroupBallotKHR,
    • readFirstInvocationARB() → OpSubgroupFirstInvocationKHR, and
    • readInvocationARB() → OpSubgroupReadInvocationKHR.
    Deprecated by Vulkan 1.2

    Most of the functionality in this extension is superseded by the core Vulkan 1.1 subgroup operations. However, Vulkan 1.1 required the OpGroupNonUniformBroadcast “Id” to be constant. This restriction was removed in Vulkan 1.2 with the addition of the subgroupBroadcastDynamicId feature.

    VK_EXT_shader_subgroup_ballot
    Name String
    VK_EXT_shader_subgroup_ballot
    Extension Type
    Device extension
    Registered Extension Number
    65
    Revision
    1
    Extension and Version Dependencies
    • Requires Vulkan 1.0
    Deprecation state
    Contact
    Other Extension Metadata
    Last Modified Date
    2016-11-28
    IP Status
    No known IP claims.
    Interactions and External Dependencies
    Contributors
    • Jeff Bolz, NVIDIA
    • Neil Henning, Codeplay
    • Daniel Koch, NVIDIA Corporation

    • Field Detail

      • VK_EXT_SHADER_SUBGROUP_BALLOT_SPEC_VERSION

        public static final int VK_EXT_SHADER_SUBGROUP_BALLOT_SPEC_VERSION
        The extension specification version.
        See Also:
        Constant Field Values

      • VK_EXT_SHADER_SUBGROUP_BALLOT_EXTENSION_NAME

        public static final java.lang.String VK_EXT_SHADER_SUBGROUP_BALLOT_EXTENSION_NAME
        The extension name.
        See Also:
        Constant Field Values