88 lines
2.9 KiB
Plaintext
88 lines
2.9 KiB
Plaintext
// Copyright (c) 2016-2019 Khronos Group. This work is licensed under a
|
|
// Creative Commons Attribution 4.0 International License; see
|
|
// http://creativecommons.org/licenses/by/4.0/
|
|
|
|
include::meta/VK_KHR_variable_pointers.txt[]
|
|
|
|
*Last Modified Date*::
|
|
2017-09-05
|
|
*IP Status*::
|
|
No known IP claims.
|
|
*Interactions and External Dependencies*::
|
|
- Requires the
|
|
https://www.khronos.org/registry/spir-v/extensions/KHR/SPV_KHR_variable_pointers.html[`SPV_KHR_variable_pointers`]
|
|
SPIR-V extension.
|
|
- Promoted to Vulkan 1.1 Core
|
|
*Contributors*::
|
|
- John Kessenich, Google
|
|
- Neil Henning, Codeplay
|
|
- David Neto, Google
|
|
- Daniel Koch, Nvidia
|
|
- Graeme Leese, Broadcom
|
|
- Weifeng Zhang, Qualcomm
|
|
- Stephen Clarke, Imagination Technologies
|
|
- Jason Ekstrand, Intel
|
|
- Jesse Hall, Google
|
|
|
|
The `VK_KHR_variable_pointers` extension allows implementations to indicate
|
|
their level of support for the `SPV_KHR_variable_pointers` SPIR-V extension.
|
|
The SPIR-V extension allows shader modules to use invocation-private
|
|
pointers into uniform and/or storage buffers, where the pointer values can
|
|
be dynamic and non-uniform.
|
|
|
|
The `SPV_KHR_variable_pointers` extension introduces two capabilities.
|
|
The first, code:VariablePointersStorageBuffer, must: be supported by all
|
|
implementations of this extension.
|
|
The second, code:VariablePointers, is optional.
|
|
|
|
=== New Enum Constants
|
|
|
|
* Extending elink:VkStructureType:
|
|
** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR
|
|
|
|
=== New Structures
|
|
|
|
* slink:VkPhysicalDeviceVariablePointerFeaturesKHR
|
|
|
|
=== New SPIR-V Capabilities
|
|
|
|
* <<spirvenv-capabilities-table-variablepointers,VariablePointersStorageBuffer>>
|
|
* <<spirvenv-capabilities-table-variablepointers,VariablePointers>>
|
|
|
|
=== Promotion to Vulkan 1.1
|
|
|
|
All functionality in this extension is included in core Vulkan 1.1, with the
|
|
KHR suffix omitted, however support for the
|
|
<<features-variablePointersStorageBuffer,
|
|
pname:variablePointersStorageBuffer>> feature is made optional.
|
|
The original type, enum and command names are still available as aliases of
|
|
the core functionality.
|
|
|
|
=== Issues
|
|
|
|
1) Do we need an optional property for the SPIR-V
|
|
code:VariablePointersStorageBuffer capability or should it be mandatory when
|
|
this extension is advertised?
|
|
|
|
*RESOLVED*: Add it as a distinct feature, but make support mandatory.
|
|
Adding it as a feature makes the extension easier to include in a future
|
|
core API version.
|
|
In the extension, the feature is mandatory, so that presence of the
|
|
extension guarantees some functionality.
|
|
When included in a core API version, the feature would be optional.
|
|
|
|
2) Can support for these capabilities vary between shader stages?
|
|
|
|
*RESOLVED*: No, if the capability is supported in any stage it must be
|
|
supported in all stages.
|
|
|
|
3) Should the capabilities be features or limits?
|
|
|
|
*RESOLVED*: Features, primarily for consistency with other similar
|
|
extensions.
|
|
|
|
=== Version History
|
|
|
|
* Revision 1, 2017-03-14 (Jesse Hall and John Kessenich)
|
|
- Internal revisions
|