Hash :
62b00f86
Author :
Date :
2025-10-02T12:19:23
Vulkan: Further minimize VertexArrayVk::syncDirtyEnabledAttrib This CL splits the streaming handling into its own function: syncDirtyEnabledAttrib is now splitted into syncDirtyEnabledNonStreamingAttrib and syncDirtyEnabledStreamingAttrib. This minimize the condition check inside syncDirtyEnabledAttrib. VertexArrayVk::syncDirtyEnabledAttrib() function has a check of bufferGL->getSize() > 0 as well as hasAtLeastOneVertex. And if either of them are false, they simply point to empty buffer. This CL merges these this fallout case into hasAtLeastOneVertex and added ASSERT to ensure that if buffer size is 0, hasAtLeastOneVertex is false. Bug: b/439073246 Change-Id: I5e3592c31469d15f5321208eb0278b10e447118c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6987341 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@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 CommandResources
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::CommandResources resources;
resources.onBufferTransferWrite(dstBuffer);
resources.onBufferTransferRead(srcBuffer);
// Get a pointer to a secondary command buffer for command recording.
vk::OutsideRenderPassCommandBuffer *commandBuffer;
ANGLE_TRY(contextVk->getOutsideRenderPassCommandBuffer(resources, &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: