Fix image transitions among Samples using Dynamic_Rendering #983
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| @@ -372,6 +372,10 @@ void DynamicRendering::build_command_buffers() | |||
| { | |||
| vkb::image_layout_transition(draw_cmd_buffer, | |||
| swapchain_buffers[i].image, | |||
| VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT, | |||
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Assuming the acquisition of the swapchain image is protected by a fence guarding it from the prior present, I don't see why this wouldn't be VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT (or better yet VK_PIPELINE_STAGE_2_NONE), especially as the source layout is "undefined", meaning we don't care about the contents of this image anymore.
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From that issue I mentioned seems that changing layout will happen earlier than waiting for rasterization write to image.
I'm not that much experience Vulkan engineer, but this sentence seems reasonable:
There should be additional execution dependency with COLOR_ATTACHMENT_OUTPUT stage, otherwise image transition can start before image acquire operation finished. The destination stage is set to COLOR_ATTACHMENT_OUTPUT and this guarantees that writes from rasterization will wait. But the image layout transition happens earlier, and by setting source stage to COLOR_ATTACHMENT_OUTPUT we create execution dependency with semaphore wait operation (we chain with pWaitDstStageMask which also specifies COLOR_ATTACHMENT_OUTPUT ).
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I'll have to defer to someone with a better understanding of this than myself then. I don't quite get why the dstStage isn't sufficient to ensure the proper ordering.
With new versions of VVL for Samples which are using Dynamic_Rendering it appear synchronization issue described here:
KhronosGroup/Vulkan-ValidationLayers#7193 (comment)
I identify all Samples which are using that extension and I fix it.
Note: For Shader_Object Sample I need to wait for fix regarding latest union of C or C++ framework (It can't be tested right now)