Hash :
3515113e
Author :
Date :
2024-06-24T15:10:28
CL/Vulkan: Remove redundant state in CLImageVk Much of the image state can be queried from the front-end object. Removing all the redundant state from CLImageVk. Bug: angleproject:378103913 Change-Id: I7783674da891d1af768375e5d8efd1937c4a4177 Signed-off-by: Gowtham Tammana <g.tammana@samsung.com> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6004687 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>
ANGLE’s Vulkan back-end implementation lives in this folder.
Vulkan is an explicit graphics API. Compared to APIs like OpenGL or D3D11 explicit APIs can offer a number of significant benefits:
The vk::Renderer class represents an EGLDisplay. vk::Renderer owns shared global
resources like the VkDevice, VkQueue, the Vulkan format tables
and internal Vulkan shaders. The ContextVk class implements the back-end
of a front-end OpenGL Context. ContextVk processes state changes and handles action commands like
glDrawArrays and glDrawElements.
A render pass has three states: unstarted, started and active (we call it active in short),
started but inactive (we call it inactive in short). The back-end records commands into command
buffers via the following ContextVk APIs:
beginNewRenderPass: Writes out (aka flushes) prior pending commands into a primary command
buffer, then starts a new render pass. Returns a secondary command buffer inside a render pass
instance. getOutsideRenderPassCommandBuffer: May flush prior command buffers and close the render pass if
necessary, in addition to issuing the appropriate barriers. Returns a secondary command buffer
outside a render pass instance. getStartedRenderPassCommands: Returns a reference to the currently open render pass’ commands
buffer. onRenderPassFinished: Puts render pass into inactive state where you can not record more
commands into secondary command buffer, except in some special cases where ANGLE does some
optimization internally. flushCommandsAndEndRenderPassWithoutSubmit: Marks the end of render pass. It flushes secondary
command buffer into vulkan’s primary command buffer, puts secondary command buffer back to
unstarted state and then goes into recycler for reuse.
The back-end (mostly) records Image and Buffer barriers through additional CommandBufferAccess
APIs, the result of which is passed to getOutsideRenderPassCommandBuffer. Note that the barriers
are not actually recorded until getOutsideRenderPassCommandBuffer is called:
onBufferTransferRead and onBufferComputeShaderRead accumulate VkBuffer read barriers. onBufferTransferWrite and onBufferComputeShaderWrite accumulate VkBuffer write barriers. onBuffferSelfCopy is a special case for VkBuffer self copies. It behaves the same as write. onImageTransferRead and onImageComputerShadeRead accumulate VkImage read barriers. onImageTransferWrite and onImageComputerShadeWrite accumulate VkImage write barriers. onImageRenderPassRead and onImageRenderPassWrite accumulate VkImage barriers inside a
started RenderPass.
After the back-end records commands to the primary buffer and we flush (e.g. on swap) or when we call
vk::Renderer::finishQueueSerial, ANGLE submits the primary command buffer to a VkQueue.
See the code for more details.
In this example we’ll be recording a buffer copy command:
// Ensure that ANGLE sets proper read and write barriers for the Buffers.
vk::CommandBufferAccess access;
access.onBufferTransferWrite(dstBuffer);
access.onBufferTransferRead(srcBuffer);
// Get a pointer to a secondary command buffer for command recording.
vk::OutsideRenderPassCommandBuffer *commandBuffer;
ANGLE_TRY(contextVk->getOutsideRenderPassCommandBuffer(access, &commandBuffer));
// Record the copy command into the secondary buffer. We're done!
commandBuffer->copyBuffer(srcBuffer->getBuffer(), dstBuffer->getBuffer(), copyCount, copies);
More implementation details can be found in the doc directory: