C Specification

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

void vkCmdEndTransformFeedbackEXT(
    VkCommandBuffer                             commandBuffer,
    uint32_t                                    firstCounterBuffer,
    uint32_t                                    counterBufferCount,
    const VkBuffer*                             pCounterBuffers,
    const VkDeviceSize*                         pCounterBufferOffsets);

Parameters

  • commandBuffer is the command buffer into which the command is recorded.

  • firstCounterBuffer is the index of the first transform feedback buffer corresponding to pCounterBuffers[0] and pCounterBufferOffsets[0].

  • counterBufferCount is the size of the pCounterBuffers and pCounterBufferOffsets arrays.

  • pCounterBuffers is an optional array of buffer handles to the counter buffers used to record the current byte positions of each transform feedback buffer where the next vertex output data would be captured. This can be used by a subsequent vkCmdBeginTransformFeedbackEXT call to resume transform feedback capture from this position. It can also be used by vkCmdDrawIndirectByteCountEXT to determine the vertex count of the draw call.

  • pCounterBufferOffsets is an optional array of offsets within each of the pCounterBuffers where the counter values can be written. The location in each counter buffer at these offsets must be large enough to contain 4 bytes of data. The data stored at this location is the byte offset from the start of the transform feedback buffer binding where the next vertex data would be written. If pCounterBufferOffsets is NULL, then it is assumed the offsets are zero.

Description

Valid Usage
  • VkPhysicalDeviceTransformFeedbackFeaturesEXT::transformFeedback must be enabled

  • Transform feedback must be active

  • firstCounterBuffer must be less than VkPhysicalDeviceTransformFeedbackPropertiesEXT::maxTransformFeedbackBuffers

  • The sum of firstCounterBuffer and counterBufferCount must be less than or equal to VkPhysicalDeviceTransformFeedbackPropertiesEXT::maxTransformFeedbackBuffers

  • If counterBufferCount is not 0, and pCounterBuffers is not NULL, pCounterBuffers must be a valid pointer to an array of counterBufferCount VkBuffer handles that are either valid or VK_NULL_HANDLE

  • For each buffer handle in the array, if it is not VK_NULL_HANDLE it must reference a buffer large enough to hold 4 bytes at the corresponding offset from the pCounterBufferOffsets array

  • If pCounterBuffer is NULL, then pCounterBufferOffsets must also be NULL

  • For each buffer handle in the pCounterBuffers array that is not VK_NULL_HANDLE it must have been created with a usage value containing VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT

Valid Usage (Implicit)
  • commandBuffer must be a valid VkCommandBuffer handle

  • If counterBufferCount is not 0, and pCounterBufferOffsets is not NULL, pCounterBufferOffsets must be a valid pointer to an array of counterBufferCount VkDeviceSize values

  • commandBuffer must be in the recording state

  • The VkCommandPool that commandBuffer was allocated from must support graphics operations

  • This command must only be called inside of a render pass instance

  • Both of commandBuffer, and the elements of pCounterBuffers that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization
  • Host access to commandBuffer must be externally synchronized

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

Command Properties
Command Buffer Levels Render Pass Scope Supported Queue Types Pipeline Type

Primary
Secondary

Inside

Graphics

See Also

VkBuffer, VkCommandBuffer, VkDeviceSize

Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

Copyright (c) 2014-2019 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.