minecraftvulkan/engine/xe_descriptors.cpp

#include "xe_descriptors.hpp"

#include <cassert>
#include <stdexcept>
#include <iostream>

namespace xe {

DescriptorSetLayout::Builder &DescriptorSetLayout::Builder::addBinding(
    uint32_t binding,
    VkDescriptorType descriptorType,
    VkShaderStageFlags stageFlags,
    VkSampler *sampler,
    uint32_t count) {
  assert(bindings.count(binding) == 0 && "Binding already in use");
  VkDescriptorSetLayoutBinding layoutBinding{};
  layoutBinding.binding = binding;
  layoutBinding.descriptorType = descriptorType;
  layoutBinding.descriptorCount = count;
  layoutBinding.stageFlags = stageFlags;
  layoutBinding.pImmutableSamplers = sampler;
  bindings[binding] = layoutBinding;
  return *this;
}

std::unique_ptr<DescriptorSetLayout> DescriptorSetLayout::Builder::build() const {
  return std::make_unique<DescriptorSetLayout>(xeDevice, bindings);
}

DescriptorSetLayout::DescriptorSetLayout(
    Device &xeDevice, std::unordered_map<uint32_t, VkDescriptorSetLayoutBinding> bindings)
    : xeDevice{xeDevice}, bindings{bindings} {
  std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings{};
  for (auto kv : bindings) {
    setLayoutBindings.push_back(kv.second);
  }

  VkDescriptorSetLayoutCreateInfo descriptorSetLayoutInfo{};
  descriptorSetLayoutInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
  descriptorSetLayoutInfo.bindingCount = static_cast<uint32_t>(setLayoutBindings.size());
  descriptorSetLayoutInfo.pBindings = setLayoutBindings.data();

  if (vkCreateDescriptorSetLayout(
          xeDevice.device(),
          &descriptorSetLayoutInfo,
          nullptr,
          &descriptorSetLayout) != VK_SUCCESS) {
    throw std::runtime_error("failed to create descriptor set layout!");
  }
}

DescriptorSetLayout::~DescriptorSetLayout() {
  vkDestroyDescriptorSetLayout(xeDevice.device(), descriptorSetLayout, nullptr);
}

DescriptorPool::Builder &DescriptorPool::Builder::addPoolSize(
    VkDescriptorType descriptorType, uint32_t count) {
  poolSizes.push_back({descriptorType, count});
  return *this;
}

DescriptorPool::Builder &DescriptorPool::Builder::setPoolFlags(
    VkDescriptorPoolCreateFlags flags) {
  poolFlags = flags;
  return *this;
}
DescriptorPool::Builder &DescriptorPool::Builder::setMaxSets(uint32_t count) {
  maxSets = count;
  return *this;
}

std::unique_ptr<DescriptorPool> DescriptorPool::Builder::build() const {
  return std::make_unique<DescriptorPool>(xeDevice, maxSets, poolFlags, poolSizes);
}

DescriptorPool::DescriptorPool(
    Device &xeDevice,
    uint32_t maxSets,
    VkDescriptorPoolCreateFlags poolFlags,
    const std::vector<VkDescriptorPoolSize> &poolSizes)
    : xeDevice{xeDevice} {
  VkDescriptorPoolCreateInfo descriptorPoolInfo{};
  descriptorPoolInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
  descriptorPoolInfo.poolSizeCount = static_cast<uint32_t>(poolSizes.size());
  descriptorPoolInfo.pPoolSizes = poolSizes.data();
  descriptorPoolInfo.maxSets = maxSets;
  descriptorPoolInfo.flags = poolFlags;

  if (vkCreateDescriptorPool(xeDevice.device(), &descriptorPoolInfo, nullptr, &descriptorPool) !=
      VK_SUCCESS) {
    throw std::runtime_error("failed to create descriptor pool!");
  }
}

DescriptorPool::~DescriptorPool() {
  vkDestroyDescriptorPool(xeDevice.device(), descriptorPool, nullptr);
}

bool DescriptorPool::allocateDescriptor(
    const VkDescriptorSetLayout descriptorSetLayout, VkDescriptorSet &descriptor) const {
  VkDescriptorSetAllocateInfo allocInfo{};
  allocInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
  allocInfo.descriptorPool = descriptorPool;
  allocInfo.pSetLayouts = &descriptorSetLayout;
  allocInfo.descriptorSetCount = 1;

  VkResult result = vkAllocateDescriptorSets(xeDevice.device(), &allocInfo, &descriptor);
  if (result != VK_SUCCESS) {
    if(result == VK_ERROR_OUT_OF_POOL_MEMORY) {
      std::cout << "[ERROR] failed to allocate descriptor set, descriptor pool out of memory" << "\n";
    }
    return false;
  }
  return true;
}

void DescriptorPool::freeDescriptors(std::vector<VkDescriptorSet> &descriptors) const {
  vkFreeDescriptorSets(
      xeDevice.device(),
      descriptorPool,
      static_cast<uint32_t>(descriptors.size()),
      descriptors.data());
}

void DescriptorPool::resetPool() {
  vkResetDescriptorPool(xeDevice.device(), descriptorPool, 0);
}

DescriptorWriter::DescriptorWriter(DescriptorSetLayout &setLayout, DescriptorPool &pool)
    : setLayout{setLayout}, pool{pool} {}

DescriptorWriter &DescriptorWriter::writeBuffer(
    uint32_t binding, VkDescriptorBufferInfo *bufferInfo) {
  assert(setLayout.bindings.count(binding) == 1 && "Layout does not contain specified binding");

  auto &bindingDescription = setLayout.bindings[binding];

  assert(
      bindingDescription.descriptorCount == 1 &&
      "Binding single descriptor info, but binding expects multiple");

  VkWriteDescriptorSet write{};
  write.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
  write.descriptorType = bindingDescription.descriptorType;
  write.dstBinding = binding;
  write.pBufferInfo = bufferInfo;
  write.descriptorCount = 1;

  writes.push_back(write);
  return *this;
}

DescriptorWriter &DescriptorWriter::writeImage(
    uint32_t binding, VkDescriptorImageInfo *imageInfo) {
  assert(setLayout.bindings.count(binding) == 1 && "Layout does not contain specified binding");

  auto &bindingDescription = setLayout.bindings[binding];

  assert(
      bindingDescription.descriptorCount == 1 &&
      "Binding single descriptor info, but binding expects multiple");

  VkWriteDescriptorSet write{};
  write.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
  write.descriptorType = bindingDescription.descriptorType;
  write.dstBinding = binding;
  write.pImageInfo = imageInfo;
  write.descriptorCount = 1;

  writes.push_back(write);
  return *this;
}

DescriptorWriter &DescriptorWriter::writeImageArray(
  uint32_t binding, std::vector<VkDescriptorImageInfo> *imageInfos) {
  assert(setLayout.bindings.count(binding) == 1 && "Layout does not contain specified binding");

  auto &bindingDescription = setLayout.bindings[binding];
  
  for(auto &imageInfo : *imageInfos) {
    VkWriteDescriptorSet write{};
    write.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    write.descriptorType = bindingDescription.descriptorType;
    write.dstBinding = binding;
    write.dstArrayElement = 0;
    write.pImageInfo = imageInfos->data();
    write.descriptorCount = imageInfos->size();
    write.pBufferInfo = 0;

    writes.push_back(write);
  }
  return *this;
}

bool DescriptorWriter::build(VkDescriptorSet &set) {
  bool success = pool.allocateDescriptor(setLayout.getDescriptorSetLayout(), set);
  if (!success) {
    return false;
  }
  overwrite(set);
  return true;
}

void DescriptorWriter::overwrite(VkDescriptorSet &set) {
  for (auto &write : writes) {
    write.dstSet = set;
  }
  vkUpdateDescriptorSets(pool.xeDevice.device(), writes.size(), writes.data(), 0, nullptr);
}

}