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b557dd2167
* Update release number to 96.
Public Issues:
* Fix typo in `vk.xml` for `structextends` attribute of
slink:VkPhysicalDeviceShadingRateImagePropertiesNV (public PR 870).
* Fix links in optimized PDF output (public PR 879).
Internal Issues:
* Add a link to GitHub contributors in the <<credits, Other Credits>>
section (internal issue 808).
* Clarify the behavior of command aliases described in the <<versions,Core
Revisions>> and <<initialization-functionpointers, Command Function
Pointers>> sections and the registry schema document with respect to
whether they are or are not the same entry point, and what the behaviour
of the ftext:vkGet*ProcAddr commands is for each alias (internal issue
1462).
* Update slink:VkPipelineShaderStageCreateInfo valid usage statements for
writing to code:Layer and code:viewportIndex to apply to any vertex
processing stage (internal issue 1475).
* Make sparse image creation optional for Y'C~B~C~R~ formats in the
<<features-required-format-support, Required Format Support>> section
and the <<features-formats-requiring-sampler-ycbcr-conversion, Formats
requiring sampler Y'C~B~C~R~ conversion for
ename:VK_IMAGE_ASPECT_COLOR_BIT image views>> table (internal issue
1476).
* Modify the valid usage statement for
flink:vkCmdDrawIndirectByteCountEXT::pname:vertexStride to use the
pname:maxTransformFeedbackBufferDataStride limit rather than the
pname:maxVertexInputBindingStride limit, which is a better match for
transform feedback related operations (internal issue 1487).
* Changed all members of slink:VkPhysicalDevicePCIBusInfoPropertiesEXT to
have the `uint32_t` type. This is an imcompatible change to an EXT
that's very recently released; although this is against usual Vulkan WG
policy, we discussed and consider this an acceptable risk, but have
polled the mesa-dev list in case there are use cases we missed (internal
issue 1492).
* Set spec vetsion to 1 for `VK_GOOGLE_hlsl_functionality1` and
`VK_GOOGLE_decorate_string` in `vk.xml` (internal MR 2948).
* Remove redundant valid usage statement `VkImageCreateInfo-pNext-02395`
(internal MR 2950).
* Add `check_spec_links.py` script, use it in Gitlab CI, and fix many
minor markup issues discovered by the script (internal MR 2955).
* Update `BUILD.md` to the current Ruby version (2.5.3), and make some
corresponding updates to per-platform build instructions (internal MR
2956).
* Fix binding numbers and other details in
flink:vkUpdateDescriptorSetWithTemplate.txt example code blocks
(internal MR 2960).
* Remove some nautovalidity="true" in `vk.xml` for NV extensions where
it's clearly wrong (internal MR 2970).
142 lines
4.9 KiB
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142 lines
4.9 KiB
Plaintext
include::meta/VK_EXT_transform_feedback.txt[]
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*Last Modified Data*::
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2018-10-09
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*Contributors*::
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- Baldur Karlsson, Valve
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- Boris Zanin, Mobica
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- Daniel Rakos, AMD
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- Donald Scorgie, Imagination
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- Henri Verbeet, CodeWeavers
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- Jan-Harald Fredriksen, Arm
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- Jason Ekstrand, Intel
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- Jeff Bolz, NVIDIA
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- Jesse Barker, Unity
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- Jesse Hall, Google
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- Pierre-Loup Griffais, Valve
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- Philip Rebohle, DXVK
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- Ruihao Zhang, Qualcomm
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- Samuel Pitoiset, Valve
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- Slawomir Grajewski, Intel
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- Stu Smith, Imagination Technologies
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This extension adds transform feedback to the Vulkan API by exposing the
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SPIR-V code:TransformFeedback and code:GeometryStreams capabilities to
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capture vertex, tessellation or geometry shader outputs to one or more
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buffers.
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It adds API functionality to bind transform feedback buffers to capture the
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primitives emitted by the graphics pipeline from SPIR-V outputs decorated
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for transform feedback.
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The transform feedback capture can be paused and resumed by way of storing
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and retrieving a byte counter.
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The captured data can be drawn again where the vertex count is derived from
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the byte counter without CPU intervention.
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If the implementation is capable, a vertex stream other than zero can be
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rasterized.
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All these features are designed to match the full capabilities of OpenGL
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core transform feedback functionality and beyond.
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Many of the features are optional to allow base OpenGL ES GPUs to also
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implement this extension.
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The primary purpose of the functionality exposed by this extension is to
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support translation layers from other 3D APIs.
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This functionality is not considered forward looking, and is not expected to
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be promoted to a KHR extension or to core Vulkan.
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Unless this is needed for translation, it is recommended that developers use
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alternative techniques of using the GPU to process and capture vertex data.
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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_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_FEATURES_EXT
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** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_PROPERTIES_EXT
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** ename:VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_STREAM_CREATE_INFO_EXT
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* Extending elink:VkQueryType:
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** ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT
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* Extending elink:VkBufferUsageFlagBits:
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** ename:VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT
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** ename:VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT
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* Extending elink:VkAccessFlagBits:
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** ename:VK_ACCESS_TRANSFORM_FEEDBACK_WRITE_BIT_EXT
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** ename:VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT
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** ename:VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT
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* Extending elink:VkPipelineStageFlagBits:
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** ename:VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT
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=== New Enums
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* tlink:VkPipelineRasterizationStateStreamCreateFlagsEXT
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=== New Structures
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* Extending slink:VkPhysicalDeviceFeatures2:
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** slink:VkPhysicalDeviceTransformFeedbackFeaturesEXT
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* Extending slink:VkPhysicalDeviceProperties2:
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** slink:VkPhysicalDeviceTransformFeedbackPropertiesEXT
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* Extending slink:VkPipelineRasterizationStateCreateInfo
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** slink:VkPipelineRasterizationStateStreamCreateInfoEXT
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=== New Functions
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* flink:vkCmdBindTransformFeedbackBuffersEXT
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* flink:vkCmdBeginTransformFeedbackEXT
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* flink:vkCmdEndTransformFeedbackEXT
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* flink:vkCmdBeginQueryIndexedEXT
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* flink:vkCmdEndQueryIndexedEXT
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* flink:vkCmdDrawIndirectByteCountEXT
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=== Issues
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1) Should we include pause/resume functionality?
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*RESOLVED*: Yes, this is needed to ease layering other APIs which have this
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functionality.
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To pause use fname:vkCmdEndTransformFeedbackEXT and provide valid buffer
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handles in the pname:pCounterBuffers array and offsets in the
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pname:pCounterBufferOffsets array for the implementation to save the resume
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points.
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Then to resume use fname:vkCmdBeginTransformFeedbackEXT with the previous
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pname:pCounterBuffers and pname:pCounterBufferOffsets values.
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Between the pause and resume there needs to be a memory barrier for the
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counter buffers with a source access of
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ename:VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT at pipeline stage
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ename:VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT to a destination access
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of ename:VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT at pipeline stage
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ename:VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT.
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2) How does this interact with multiview?
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*RESOLVED*: Transform feedback cannot be made active in a render pass with
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multiview enabled.
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3) How should queries be done?
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*RESOLVED*: There is a new query type
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ename:VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT.
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A query pool created with this type will capture 2 integers -
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numPrimitivesWritten and numPrimitivesNeeded - for the specified vertex
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stream output from the last vertex processing stage.
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The vertex stream output queried is zero by default, but can be specified
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with the new fname:vkCmdBeginQueryIndexedEXT and
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fname:vkCmdEndQueryIndexedEXT commands.
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=== Version History
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* Revision 1, 2018-10-09 (Piers Daniell)
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- Internal revisions
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