VulkanHub
Function Prototype

vkCmdBeginTransformFeedback2EXT

Make transform feedback active in the command buffer

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

void vkCmdBeginTransformFeedback2EXT(
    VkCommandBuffer   commandBuffer,
    uint32_t                            firstCounterRange,
    uint32_t            counterRangeCount,
    const VkBindTransformFeedbackBuffer2InfoEXT* pCounterInfos);
  • 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.

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::transformFeedbackmust 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