101 lines
3.8 KiB
Plaintext
101 lines
3.8 KiB
Plaintext
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include::meta/VK_EXT_descriptor_indexing.txt[]
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*Status*::
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Complete
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*Last Modified Data*::
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2017-10-02
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*Contributors*::
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- Jeff Bolz, NVIDIA
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- Daniel Rakos, AMD
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- Slawomir Grajewski, Intel
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- Tobias Hector, Imagination Technologies
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This extension adds several small features which together enable
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applications to create large descriptor sets containing substantially all of
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their resources, and selecting amongst those resources with dynamic
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(non-uniform) indexes in the shader.
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There are feature enables and SPIR-V capabilities for non-uniform descriptor
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indexing in the shader, and non-uniform indexing in the shader requires use
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of a new code:NonUniformEXT decoration defined in the
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+SPV_EXT_descriptor_indexing+ SPIR-V extension.
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There are descriptor set layout binding creation flags enabling several
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features:
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* Descriptors can be updated after they are bound to a command buffer,
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such that the execution of the command buffer reflects the most recent
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update to the descriptors.
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* Descriptors that are not used by any pending command buffers can be
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updated, which enables writing new descriptors for frame N+1 while frame
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N is executing.
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* Relax the requirement that all descriptors in a binding that is
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"statically used" must be valid, such that descriptors that are not
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accessed by a submission need not be valid and can be updated while that
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submission is executing.
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* The final binding in a descriptor set layout can have a variable size
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(and unsized arrays of resources are allowed in the
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+GL_EXT_nonuniform_qualifier+ and +SPV_EXT_descriptor_indexing+
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extensions).
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Note that it is valid for multiple descriptor arrays in a shader to use the
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same set and binding number, as long as they are all compatible with the
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descriptor type in the pipeline layout.
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This means a single array binding in the descriptor set can serve multiple
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texture dimensionalities, or an array of buffer descriptors can be used with
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multiple different block layouts.
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There are new descriptor set layout and descriptor pool creation flags that
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are required to opt in to the update-after-bind functionality, and there are
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separate pname:maxPerStage* and pname:maxDescriptorSet* limits that apply to
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these descriptor set layouts which may: be much higher than the pre-existing
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limits.
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The old limits only count descriptors in non-updateAfterBind descriptor set
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layouts, and the new limits count descriptors in all descriptor set layouts
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in the pipeline layout.
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=== New Object Types
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None.
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=== New Enum Constants
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* Extending elink:VkStructureType:
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** ename:VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT
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** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT
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** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT
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** ename:VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT
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** ename:VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT
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* Extending elink:VkDescriptorPoolCreateFlagBits:
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** ename:VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT
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* Extending elink:VkDescriptorSetLayoutCreateFlagBits:
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** ename:VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT
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* Extending elink:VkResult:
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** ename:VK_ERROR_FRAGMENTATION_EXT
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=== New Enums
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* elink:VkDescriptorBindingFlagBitsEXT
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=== New Structures
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* slink:VkDescriptorSetLayoutBindingFlagsCreateInfoEXT
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* slink:VkPhysicalDeviceDescriptorIndexingFeaturesEXT
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* slink:VkPhysicalDeviceDescriptorIndexingPropertiesEXT
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* slink:VkDescriptorSetVariableDescriptorCountAllocateInfoEXT
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* slink:VkDescriptorSetVariableDescriptorCountLayoutSupportEXT
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=== New Functions
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None.
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=== Issues
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None.
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=== Version History
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* Revision 1, 2017-07-26 (Jeff Bolz)
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- Internal revisions
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