In addition to allocating descriptor sets and binding them to a command buffer, an application can record descriptor updates into the command buffer.
To push descriptor updates into a command buffer, call:
void vkCmdPushDescriptorSetKHR( VkCommandBuffer commandBuffer, VkPipelineBindPoint pipelineBindPoint, VkPipelineLayout layout, uint32_t set, uint32_t descriptorWriteCount, const VkWriteDescriptorSet* pDescriptorWrites);
commandBufferis the command buffer that the descriptors will be recorded in.
pipelineBindPointis a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. There is a separate set of push descriptor bindings for each of graphics and compute, so binding one does not disturb the other.
layoutis a VkPipelineLayout object used to program the bindings.
setis the set number of the descriptor set in the pipeline layout that will be updated.
descriptorWriteCountis the number of elements in the
pDescriptorWritesis a pointer to an array of VkWriteDescriptorSet structures describing the descriptors to be updated.
Push descriptors are a small bank of descriptors whose storage is internally managed by the command buffer rather than being written into a descriptor set and later bound to a command buffer. Push descriptors allow for incremental updates of descriptors without managing the lifetime of descriptor sets.
When a command buffer begins recording, all push descriptors are undefined.
Push descriptors can be updated incrementally and cause shaders to use the
updated descriptors for subsequent rendering commands (either compute or
graphics, according to the
pipelineBindPoint) until the descriptor is
overwritten, or else until the set is disturbed as described in
Pipeline Layout Compatibility.
When the set is disturbed or push descriptors with a different descriptor
set layout are set, all push descriptors are undefined.
Push descriptors that are statically used by a
pipeline must not be undefined at the time that a draw or dispatch command
is recorded to execute using that pipeline.
This includes immutable sampler descriptors, which must be pushed before
they are accessed by a pipeline (the immutable samplers are pushed, rather
than the samplers in
Push descriptors that are not statically used can remain undefined.
Push descriptors do not use dynamic offsets.
Instead, the corresponding non-dynamic descriptor types can be used and the
offset member of VkDescriptorBufferInfo can be changed each
time the descriptor is written.
Each element of
pDescriptorWrites is interpreted as in
VkWriteDescriptorSet, except the
dstSet member is ignored.
To push an immutable sampler, use a VkWriteDescriptorSet with
dstArrayElement selecting the immutable sampler’s
If the descriptor type is
pImageInfo parameter is ignored and the immutable sampler is taken
from the push descriptor set layout in the pipeline layout.
If the descriptor type is
sampler member of the
pImageInfo parameter is ignored and
the immutable sampler is taken from the push descriptor set layout in the
For more information, see the Vulkan Specification at URL
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.