Fix barrier issues in computecloth #1103
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| std::array<VkBufferMemoryBarrier, 2> bufferBarriers; | ||
| bufferBarriers[0] = vks::initializers::bufferMemoryBarrier(); | ||
| bufferBarriers[0].srcAccessMask = VK_ACCESS_SHADER_READ_BIT; | ||
| bufferBarriers[0].dstAccessMask = VK_ACCESS_SHADER_WRITE_BIT; | ||
| bufferBarriers[0].buffer = storageBuffers.input.buffer; | ||
| bufferBarriers[1] = vks::initializers::bufferMemoryBarrier(); | ||
| bufferBarriers[1].srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT; | ||
| bufferBarriers[1].dstAccessMask = VK_ACCESS_SHADER_READ_BIT; | ||
| bufferBarriers[1].buffer = storageBuffers.output.buffer; | ||
| if (reverse) { | ||
| std::swap(bufferBarriers[0].buffer, bufferBarriers[1].buffer); | ||
| } |
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This is the main bug fix for #1097
The dispatch loop uses the descriptor sets to alternate between between reading from input and writing to output and vice versa, but the original barriers don't match that. They always moved both buffers from write to read mode.
Assuming the most recent data is in input at the start of every frame, and it's in read mode while the output buffer is in write mode, then on even dispatches we want to move input to write and output to read. On odd dispatches we want to move them back to the original state.
| vulkanDevice->createBuffer( | ||
| VK_BUFFER_USAGE_VERTEX_BUFFER_BIT | VK_BUFFER_USAGE_STORAGE_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT, | ||
| VK_BUFFER_USAGE_STORAGE_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT | VK_BUFFER_USAGE_TRANSFER_SRC_BIT, |
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As noted, storageBuffers.input is never accessed on the graphics queue, so no need for the vertex buffer bit, but I do need to copy from it to the output buffer in the compute queue, so added the transfer src bit.
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This is to fix #1097
Notes inline
The updated sample passes with the Vulkan Configurator set to enable the validation profile and with it set to the synchronization profile, with no errors or warnings.