vkCmdBeginTransformFeedback2EXT(3)

C Specification

Transform feedback for specific transform feedback buffers is made active by calling:

// Provided by VK_KHR_device_address_commands with VK_EXT_transform_feedback
void vkCmdBeginTransformFeedback2EXT(
    VkCommandBuffer                             commandBuffer,
    uint32_t                                    firstCounterRange,
    uint32_t                                    counterRangeCount,
    const VkBindTransformFeedbackBuffer2InfoEXT* pCounterInfos);

Parameters

commandBuffer is the command buffer into which the command is recorded.
firstCounterRange is the index of the first transform feedback buffer corresponding to pCounterInfos[0].
counterRangeCount is the size of the pCounterRanges array.
pCounterInfos is NULL or a pointer to an array of VkBindTransformFeedbackBuffer2InfoEXT structures defining memory ranges containing counters used to resume transform feedback from a previous location.

Description

If pCounterInfos is NULL, it is equivalent to an array of VkBindTransformFeedbackBuffer2InfoEXT structures with each element having a addressRange.size of 0.

If the addressRange.size of an element of pCounterInfos at index i is 0, transform feedback data written to XfbBuffer with a XFB Buffer Number equal to the sum of i and firstCounterRange will be written starting at an offset of 0 in the bound transform feedback buffer. If the addressRange.size of an element of pCounterInfos at index i is not 0, it will instead be written starting at an offset equal to the 32-bit value found at pCounterInfos[i].addressRange.address.

The active transform feedback buffers will capture primitives emitted from the corresponding XfbBuffer in the bound graphics pipeline. Any XfbBuffer emitted that does not output to an active transform feedback buffer will not be captured.

Valid Usage

VUID-vkCmdBeginTransformFeedback2EXT-transformFeedback-02366
VkPhysicalDeviceTransformFeedbackFeaturesEXT::transformFeedback must be enabled
VUID-vkCmdBeginTransformFeedback2EXT-None-02367
Transform feedback must not be active
VUID-vkCmdBeginTransformFeedback2EXT-firstCounter-02368
firstCounterRange must be less than VkPhysicalDeviceTransformFeedbackPropertiesEXT::maxTransformFeedbackBuffers
VUID-vkCmdBeginTransformFeedback2EXT-firstCounter-02369
The sum of firstCounterRange and counterRangeCount must be less than or equal to VkPhysicalDeviceTransformFeedbackPropertiesEXT::maxTransformFeedbackBuffers
VUID-vkCmdBeginTransformFeedback2EXT-firstCounter-09630
The sum of firstCounterRange and counterRangeCount must be less than or equal to the number of transform feedback buffers bound by vkCmdBindTransformFeedbackBuffers2EXT
VUID-vkCmdBeginTransformFeedback2EXT-None-06233
If the shaderObject feature is not enabled, a valid graphics pipeline must be bound to VK_PIPELINE_BIND_POINT_GRAPHICS
VUID-vkCmdBeginTransformFeedback2EXT-None-04128
The last pre-rasterization shader stage of the bound graphics pipeline must have been declared with the Xfb execution mode
VUID-vkCmdBeginTransformFeedback2EXT-None-02373
Transform feedback must not be made active in a render pass instance with multiview enabled
VUID-vkCmdBeginTransformFeedback2EXT-None-10656
This command must not be recorded when per-tile execution model is enabled

VUID-vkCmdBeginTransformFeedback2EXT-pCounterInfos-13093
Each element of pCounterInfos must have a addressRange.size that is either 0 or greater than or equal to 4
VUID-vkCmdBeginTransformFeedback2EXT-pCounterInfos-13094
For each element of pCounterInfos with a non-zero address, the buffer the address was queried from must have been created with the VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT usage flag set

Valid Usage (Implicit)

VUID-vkCmdBeginTransformFeedback2EXT-commandBuffer-parameter
commandBuffer must be a valid VkCommandBuffer handle
VUID-vkCmdBeginTransformFeedback2EXT-pCounterInfos-parameter
If counterRangeCount is not 0, and pCounterInfos is not NULL, pCounterInfos must be a valid pointer to an array of counterRangeCount valid VkBindTransformFeedbackBuffer2InfoEXT structures
VUID-vkCmdBeginTransformFeedback2EXT-commandBuffer-recording
commandBuffer must be in the recording state
VUID-vkCmdBeginTransformFeedback2EXT-commandBuffer-cmdpool
The VkCommandPool that commandBuffer was allocated from must support VK_QUEUE_GRAPHICS_BIT operations
VUID-vkCmdBeginTransformFeedback2EXT-renderpass
This command must only be called inside of a render pass instance
VUID-vkCmdBeginTransformFeedback2EXT-videocoding
This command must only be called outside of a video coding scope

Host Synchronization

Host access to commandBuffer must be externally synchronized
Host access to the VkCommandPool that commandBuffer was allocated from must be externally synchronized