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Reworked compute shader n-body synchronization

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This commit is contained in:
Sascha Willems 2019-10-13 09:40:31 +02:00
parent 958f0cb65e
commit 0e9ab19fad
1 changed files with 10 additions and 49 deletions
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59
examples/computenbody/computenbody.cpp
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@ -184,7 +184,7 @@ public:
drawUI(drawCmdBuffers[i]);
vkCmdEndRenderPass(drawCmdBuffers[i]);
VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
}
@ -196,41 +196,20 @@ public:
VK_CHECK_RESULT(vkBeginCommandBuffer(compute.commandBuffer, &cmdBufInfo));
// Compute particle movement
// First pass: Calculate particle movement
// -------------------------------------------------------------------------------------------------------
vkCmdBindPipeline(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineCalculate);
vkCmdBindDescriptorSets(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineLayout, 0, 1, &compute.descriptorSet, 0, 0);
vkCmdDispatch(compute.commandBuffer, numParticles / 256, 1, 1);
// Add memory barrier to ensure that the (graphics) vertex shader has fetched attributes before compute starts to write to the buffer
// Add memory barrier to ensure that the computer shader has finished writing to the buffer
VkBufferMemoryBarrier bufferBarrier = vks::initializers::bufferMemoryBarrier();
bufferBarrier.buffer = compute.storageBuffer.buffer;
bufferBarrier.size = compute.storageBuffer.descriptor.range;
bufferBarrier.srcAccessMask = VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT; // Vertex shader invocations have finished reading from the buffer
bufferBarrier.dstAccessMask = VK_ACCESS_SHADER_WRITE_BIT; // Compute shader wants to write to the buffer
bufferBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
bufferBarrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
// Transfer ownership if compute and graphics queue familiy indices differ
bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
vkCmdPipelineBarrier(
compute.commandBuffer,
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT,
VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
VK_FLAGS_NONE,
0, nullptr,
1, &bufferBarrier,
0, nullptr);
vkCmdBindPipeline(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineCalculate);
vkCmdBindDescriptorSets(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineLayout, 0, 1, &compute.descriptorSet, 0, 0);
// First pass: Calculate particle movement
// -------------------------------------------------------------------------------------------------------
vkCmdDispatch(compute.commandBuffer, numParticles / 256, 1, 1);
// Add memory barrier to ensure that compute shader has finished writing to the buffer
bufferBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT; // Compute shader has finished writes to the buffer
bufferBarrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
bufferBarrier.buffer = compute.storageBuffer.buffer;
bufferBarrier.size = compute.storageBuffer.descriptor.range;
// No ownership transfer necessary
bufferBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
bufferBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
bufferBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
vkCmdPipelineBarrier(
@ -246,24 +225,6 @@ public:
// -------------------------------------------------------------------------------------------------------
vkCmdBindPipeline(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineIntegrate);
vkCmdDispatch(compute.commandBuffer, numParticles / 256, 1, 1);
// Add memory barrier to ensure that compute shader has finished writing to the buffer
// Without this the (rendering) vertex shader may display incomplete results (partial data from last frame)
bufferBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT; // Compute shader has finished writes to the buffer
bufferBarrier.dstAccessMask = VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT; // Vertex shader invocations want to read from the buffer
bufferBarrier.buffer = compute.storageBuffer.buffer;
bufferBarrier.size = compute.storageBuffer.descriptor.range;
// Transfer ownership if compute and graphics queue familiy indices differ
bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
vkCmdPipelineBarrier(
compute.commandBuffer,
VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT,
VK_FLAGS_NONE,
0, nullptr,
1, &bufferBarrier,
0, nullptr);
vkEndCommandBuffer(compute.commandBuffer);
}