Jeroen Bakker
61b457d390
**What are push constants?** Push constants is a way to quickly provide a small amount of uniform data to shaders. It should be much quicker than UBOs but a huge limitation is the size of data - spec requires 128 bytes to be available for a push constant range. **What are the challenges with push constants?** The challenge with push constants is that the limited available size. According to the Vulkan spec each platform should at least have 128 bytes reserved for push constants. Current Mesa/AMD drivers supports 256 bytes, but Mesa/Intel is only 128 bytes. **What is our solution?** Some shaders of Blender uses more than these boundaries. When more data is needed push constants will not be used, but the shader will be patched to use an uniform buffer instead. This mechanism will be part of the Vulkan backend and shader developers should not see any difference on API level. **Known limitations** Current state of the vulkan backend does not track resources that are in the command queue. This patch includes some test cases that identified this issue as well. See #104771. Pull Request #104880
75 lines
2.1 KiB
C++
75 lines
2.1 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright 2023 Blender Foundation. All rights reserved. */
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/** \file
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* \ingroup gpu
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*/
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#include "vk_pipeline.hh"
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#include "vk_context.hh"
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#include "vk_memory.hh"
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namespace blender::gpu {
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VKPipeline::VKPipeline(VkPipeline vk_pipeline,
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VKDescriptorSet &&descriptor_set,
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VKPushConstants &&push_constants)
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: vk_pipeline_(vk_pipeline),
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descriptor_set_(std::move(descriptor_set)),
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push_constants_(std::move(push_constants))
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{
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}
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VKPipeline::~VKPipeline()
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{
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VK_ALLOCATION_CALLBACKS
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VkDevice vk_device = VKContext::get()->device_get();
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if (vk_pipeline_ != VK_NULL_HANDLE) {
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vkDestroyPipeline(vk_device, vk_pipeline_, vk_allocation_callbacks);
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}
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}
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VKPipeline VKPipeline::create_compute_pipeline(
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VKContext &context,
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VkShaderModule compute_module,
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VkDescriptorSetLayout &descriptor_set_layout,
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VkPipelineLayout &pipeline_layout,
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const VKPushConstants::Layout &push_constants_layout)
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{
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VK_ALLOCATION_CALLBACKS
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VkDevice vk_device = context.device_get();
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VkComputePipelineCreateInfo pipeline_info = {};
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pipeline_info.sType = VK_STRUCTURE_TYPE_COMPUTE_PIPELINE_CREATE_INFO;
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pipeline_info.flags = 0;
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pipeline_info.stage = {};
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pipeline_info.stage.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
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pipeline_info.stage.flags = 0;
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pipeline_info.stage.stage = VK_SHADER_STAGE_COMPUTE_BIT;
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pipeline_info.stage.module = compute_module;
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pipeline_info.layout = pipeline_layout;
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pipeline_info.stage.pName = "main";
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VkPipeline vk_pipeline;
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if (vkCreateComputePipelines(
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vk_device, nullptr, 1, &pipeline_info, vk_allocation_callbacks, &vk_pipeline) !=
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VK_SUCCESS) {
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return VKPipeline();
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}
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VKDescriptorSet descriptor_set = context.descriptor_pools_get().allocate(descriptor_set_layout);
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VKPushConstants push_constants(&push_constants_layout);
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return VKPipeline(vk_pipeline, std::move(descriptor_set), std::move(push_constants));
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}
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VkPipeline VKPipeline::vk_handle() const
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{
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return vk_pipeline_;
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}
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bool VKPipeline::is_valid() const
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{
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return vk_pipeline_ != VK_NULL_HANDLE;
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}
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} // namespace blender::gpu
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