Package org.lwjgl.vulkan

Class EXTDescriptorIndexing

java.lang.Object

org.lwjgl.vulkan.EXTDescriptorIndexing

public final class EXTDescriptorIndexing
extends java.lang.Object

This extension adds several small features which together enable applications to create large descriptor sets containing substantially all of their resources, and selecting amongst those resources with dynamic (non-uniform) indexes in the shader. There are feature enables and SPIR-V capabilities for non-uniform descriptor indexing in the shader, and non-uniform indexing in the shader requires use of a new NonUniformEXT decoration defined in the SPV_EXT_descriptor_indexing SPIR-V extension. There are descriptor set layout binding creation flags enabling several features:

• Descriptors can be updated after they are bound to a command buffer, such that the execution of the command buffer reflects the most recent update to the descriptors.
• Descriptors that are not used by any pending command buffers can be updated, which enables writing new descriptors for frame N+1 while frame N is executing.
• Relax the requirement that all descriptors in a binding that is “statically used” must be valid, such that descriptors that are not accessed by a submission need not be valid and can be updated while that submission is executing.
• The final binding in a descriptor set layout can have a variable size (and unsized arrays of resources are allowed in the GL_EXT_nonuniform_qualifier and SPV_EXT_descriptor_indexing extensions).

Note that it is valid for multiple descriptor arrays in a shader to use the same set and binding number, as long as they are all compatible with the descriptor type in the pipeline layout. This means a single array binding in the descriptor set can serve multiple texture dimensionalities, or an array of buffer descriptors can be used with multiple different block layouts.

There are new descriptor set layout and descriptor pool creation flags that are required to opt in to the update-after-bind functionality, and there are separate maxPerStage* and maxDescriptorSet* limits that apply to these descriptor set layouts which may be much higher than the pre-existing limits. The old limits only count descriptors in non-updateAfterBind descriptor set layouts, and the new limits count descriptors in all descriptor set layouts in the pipeline layout.

Name String

VK_EXT_descriptor_indexing

Extension Type

Device extension

Registered Extension Number

162

Revision

2

Extension and Version Dependencies

• Requires Vulkan 1.0
• Requires VK_KHR_get_physical_device_properties2
• Requires VK_KHR_maintenance3

Contact

• Jeff Bolz jeffbolznv

Status

Complete

Last Modified Data

2017-10-02

Contributors

• Jeff Bolz, NVIDIA
• Daniel Rakos, AMD
• Slawomir Grajewski, Intel
• Tobias Hector, Imagination Technologies

Field Summary

Fields

Modifier and Type	Field	Description
static int	VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXT	VkDescriptorBindingFlagBitsEXT - Bitmask specifying descriptor set layout binding properties
static int	VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT	Extends VkDescriptorPoolCreateFlagBits.
static int	VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT	Extends VkDescriptorSetLayoutCreateFlagBits.
static int	VK_ERROR_FRAGMENTATION_EXT	Extends VkResult.
static java.lang.String	VK_EXT_DESCRIPTOR_INDEXING_EXTENSION_NAME	The extension name.
static int	VK_EXT_DESCRIPTOR_INDEXING_SPEC_VERSION	The extension specification version.
static int	VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT	Extends VkStructureType.

Method Summary

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

VK_EXT_DESCRIPTOR_INDEXING_SPEC_VERSION

The extension specification version.

VK_EXT_DESCRIPTOR_INDEXING_EXTENSION_NAME

The extension name.

VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT, VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT, VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT, VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT, VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT

Extends VkStructureType.

Enum values:

• STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT
• STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT
• STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT
• STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT
• STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT

VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT

Extends VkDescriptorPoolCreateFlagBits.

VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT

Extends VkDescriptorSetLayoutCreateFlagBits.

VK_ERROR_FRAGMENTATION_EXT

Extends VkResult.

VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT, VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT, VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT, VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXT

VkDescriptorBindingFlagBitsEXT - Bitmask specifying descriptor set layout binding properties

Description

• DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT indicates that if descriptors in this binding are updated between when the descriptor set is bound in a command buffer and when that command buffer is submitted to a queue, then the submission will use the most recently set descriptors for this binding and the updates do not invalidate the command buffer. Descriptor bindings created with this flag are also partially exempt from the external synchronization requirement in UpdateDescriptorSetWithTemplateKHR and UpdateDescriptorSets. They can be updated concurrently with the set being bound to a command buffer in another thread, but not concurrently with the set being reset or freed.
• DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT indicates that descriptors in this binding that are not dynamically used need not contain valid descriptors at the time the descriptors are consumed. A descriptor is dynamically used if any shader invocation executes an instruction that performs any memory access using the descriptor.
• DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT indicates that descriptors in this binding can be updated after a command buffer has bound this descriptor set, or while a command buffer that uses this descriptor set is pending execution, as long as the descriptors that are updated are not used by those command buffers. If DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT is also set, then descriptors can be updated as long as they are not dynamically used by any shader invocations. If DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT is not set, then descriptors can be updated as long as they are not statically used by any shader invocations.
• DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXT indicates that this descriptor binding has a variable size that will be specified when a descriptor set is allocated using this layout. The value of descriptorCount is treated as an upper bound on the size of the binding. This must only be used for the last binding in the descriptor set layout (i.e. the binding with the largest value of binding). For the purposes of counting against limits such as maxDescriptorSet* and maxPerStageDescriptor*, the full value of descriptorCount is counted , except for descriptor bindings with a descriptor type of DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT where descriptorCount specifies the upper bound on the byte size of the binding, thus it counts against the maxInlineUniformBlockSize limit instead. .

Note

Note that while DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT and DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT both involve updates to descriptor sets after they are bound, DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT is a weaker requirement since it is only about descriptors that are not used, whereas DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT requires the implementation to observe updates to descriptors that are used.

See Also

VkDescriptorBindingFlagsEXT