src/graphics/examples/vkprimer/common/vulkan_command_buffers.cc

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "vulkan_command_buffers.h"

#include "utils.h"

VulkanCommandBuffers::VulkanCommandBuffers(std::shared_ptr<VulkanLogicalDevice> device,
                                           std::shared_ptr<VulkanCommandPool> command_pool,
                                           const VulkanFramebuffer &framebuffer,
                                           const vk::Extent2D &extent,
                                           const vk::RenderPass &render_pass,
                                           const vk::Pipeline &graphics_pipeline)
    : initialized_(false),
      device_(device),
      command_pool_(command_pool),
      command_buffers_(framebuffer.framebuffers().size()) {
  params_ = std::make_unique<InitParams>(framebuffer, extent, render_pass, graphics_pipeline);
}

VulkanCommandBuffers::InitParams::InitParams(const VulkanFramebuffer &framebuffer,
                                             const vk::Extent2D &extent,
                                             const vk::RenderPass &render_pass,
                                             const vk::Pipeline &graphics_pipeline)
    : framebuffer_(framebuffer),
      extent_(extent),
      render_pass_(render_pass),
      graphics_pipeline_(graphics_pipeline) {}

bool VulkanCommandBuffers::Init() {
  if (initialized_) {
    RTN_MSG(false, "VulkanCommandBuffers already initialized.\n");
  }

  vk::CommandBufferAllocateInfo alloc_info;
  alloc_info.setCommandBufferCount(static_cast<uint32_t>(command_buffers_.size()));
  alloc_info.setCommandPool(*command_pool_->command_pool());
  alloc_info.level = vk::CommandBufferLevel::ePrimary;

  auto rv_alloc = device_->device()->allocateCommandBuffersUnique(alloc_info);
  if (vk::Result::eSuccess != rv_alloc.result) {
    RTN_MSG(false, "VK Error: 0x%x - Failed to allocate command buffers.", rv_alloc.result);
  }
  command_buffers_ = std::move(rv_alloc.value);

  vk::ClearValue clear_color;
  clear_color.setColor(std::array<float, 4>({0.5f, 0.0f, 0.5f, 1.0f}));

  auto framebuffer_iter = params_->framebuffer_.framebuffers().begin();
  for (const auto &command_buffer : command_buffers_) {
    const auto &framebuffer = *(framebuffer_iter++);

    vk::CommandBufferBeginInfo begin_info(vk::CommandBufferUsageFlagBits::eSimultaneousUse);

    auto result = command_buffer->begin(&begin_info);
    if (vk::Result::eSuccess != result) {
      RTN_MSG(false, "VK Error: 0x%x - Failed to begin command buffer.", result);
    }

    vk::Rect2D render_area;
    render_area.extent = params_->extent_;

    vk::RenderPassBeginInfo render_pass_info;
    render_pass_info.renderPass = params_->render_pass_;
    render_pass_info.framebuffer = *framebuffer;
    render_pass_info.renderArea = render_area;
    render_pass_info.clearValueCount = 1;
    render_pass_info.pClearValues = &clear_color;

    // Record commands to render pass.
    command_buffer->beginRenderPass(&render_pass_info, vk::SubpassContents::eInline);
    command_buffer->bindPipeline(vk::PipelineBindPoint::eGraphics, params_->graphics_pipeline_);
    command_buffer->draw(3 /* vertexCount */, 1 /* instanceCount */, 0 /* firstVertex */,
                         0 /* firstInstance */);
    command_buffer->endRenderPass();

    command_buffer->end();
  }

  params_.reset();
  initialized_ = true;
  return true;
}

const std::vector<vk::UniqueCommandBuffer> &VulkanCommandBuffers::command_buffers() const {
  return command_buffers_;
}