Hash :
ca04de85
Author :
Date :
2020-03-03T09:59:42
Vulkan: blacklist VK_FORMAT_R8G8B8_UNORM Chrome makes assumptions that depend on ANGLE implementing 24bit RGB as 32 RGBX. Since that was the behavior of ANGLE for a while, remove those formats from the VK format table to force that behavior again. Test: Chrome on Fuchsia Bug: angleproject:4282 Change-Id: I22a3f07b00d7870044ed6b3326dd528721b89af8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2085043 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Michael Spang <spang@chromium.org>
ANGLE’s Vulkan back-end implementation lives in this folder.
Vulkan is an explicit graphics API. It has a lot in common with other explicit APIs such as Microsoft’s D3D12 and Apple’s Metal. Compared to APIs like OpenGL or D3D11 explicit APIs can offer a number of significant benefits:
The RendererVk class represents an EGLDisplay. RendererVk 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.
The back-end records commands into command buffers via the the following ContextVk APIs:
endRenderPassAndGetCommandBuffer: returns a secondary command buffer outside a RenderPass instance. flushAndBeginRenderPass: returns a secondary command buffer inside a RenderPass instance. flushAndGetPrimaryCommandBuffer: returns the primary command buffer. You should rarely need this API.
Note: All of these commands may write out (aka flush) prior pending commands into a primary
command buffer. When a RenderPass is open endRenderPassAndGetCommandBuffer will flush the
pending RenderPass commands. flushAndBeginRenderPass will flush out pending commands outside a
RenderPass to a primary buffer. On submit ANGLE submits the primary command buffer to a VkQueue.
If you need to record inside a RenderPass, use flushAndBeginRenderPass. Otherwise, use
endRenderPassAndGetCommandBuffer. You should rarely need to call flushAndGetPrimaryCommandBuffer.
It’s there for commands like debug labels, barriers and queries that need to be recorded serially on
the primary command buffer.
The back-end usually records Image and Buffer barriers through additional ContextVk APIs:
onBufferRead and onBufferWrite accumulate VkBuffer barriers. onImageRead and onImageWrite accumulate VkImage barriers. onRenderPassImageWrite is a special API for write barriers inside a RenderPass instance.
After the back-end records commands to the primary buffer we flush (e.g. on swap) or when we call
ContextVk::finishToSerial.
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.
ANGLE_TRY(contextVk->onBufferWrite(VK_ACCESS_TRANSFER_WRITE_BIT, destBuffer));
ANGLE_TRY(contextVk->onBufferRead(VK_ACCESS_TRANSFER_READ_BIT, srcBuffer));
# Get a pointer to a secondary command buffer for command recording. May "flush" the RP.
vk::CommandBuffer *commandBuffer;
ANGLE_TRY(contextVk->endRenderPassAndGetCommandBuffer(&commandBuffer));
# Record the copy command into the secondary buffer. We're done!
commandBuffer->copyBuffer(srcBuffer->getBuffer(), destBuffer->getBuffer(), copyCount, copies);
More implementation details can be found in the doc directory: