simple_render_system.cpp

#include "simple_render_system.hpp"

// libs
#define GLM_FORCE_RADIANS
#define GLM_FORCE_DEPTH_ZERO_TO_ONE
#include <glm/glm.hpp>
#include <glm/gtc/constants.hpp>

// std
#include <array>
#include <cassert>
#include <stdexcept>

namespace lve {

struct SimplePushConstantData {
  glm::mat2 transform{1.f};
  glm::vec2 offset;
  alignas(16) glm::vec3 color;
};

SimpleRenderSystem::SimpleRenderSystem(LveDevice &device, VkRenderPass renderPass) : lveDevice{device} {
  createPipelineLayout();
  createPipeline(renderPass);
}

SimpleRenderSystem::~SimpleRenderSystem() 
{ 
    vkDestroyPipelineLayout(lveDevice.device(), pipelineLayout, nullptr);
}

void SimpleRenderSystem::createPipelineLayout() {
  VkPushConstantRange pushConstantRange{};
  pushConstantRange.stageFlags = VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT;
  pushConstantRange.offset = 0;
  pushConstantRange.size = sizeof(SimplePushConstantData);

  VkPipelineLayoutCreateInfo pipelineLayoutInfo{};
  pipelineLayoutInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
  pipelineLayoutInfo.setLayoutCount = 0;
  pipelineLayoutInfo.pSetLayouts = nullptr;
  pipelineLayoutInfo.pushConstantRangeCount = 1;
  pipelineLayoutInfo.pPushConstantRanges = &pushConstantRange;
  if (vkCreatePipelineLayout(lveDevice.device(), &pipelineLayoutInfo, nullptr, &pipelineLayout) !=
      VK_SUCCESS) {
    throw std::runtime_error("failed to create pipeline layout!");
  }
}

void SimpleRenderSystem::createPipeline(VkRenderPass renderPass) {
  assert(pipelineLayout != nullptr && "Cannot create pipeline before pipeline layout");

  PipelineConfigInfo pipelineConfig{};
  LvePipeline::defaultPipelineConfigInfo(pipelineConfig);
  pipelineConfig.renderPass = renderPass;
  pipelineConfig.pipelineLayout = pipelineLayout;
  lvePipeline = std::make_unique<LvePipeline>(
      lveDevice,
      "shaders/simple_shader.vert.spv",
      "shaders/simple_shader.frag.spv",
      pipelineConfig);
}

void SimpleRenderSystem::renderGameObjects(VkCommandBuffer commandBuffer, float deltaTime) {
  lvePipeline->bind(commandBuffer);

  const float angularSpeed = glm::two_pi<float>() * 0.1f; // one full turn in 10 seconds
  for (auto& obj : gameObjects) {
    obj.transform2d.rotation = glm::mod(obj.transform2d.rotation + angularSpeed * deltaTime,
                                       glm::two_pi<float>());

    SimplePushConstantData push{};
    push.offset = obj.transform2d.translation;
    push.color = obj.color;
    push.transform = obj.transform2d.mat2();

    vkCmdPushConstants(
        commandBuffer,
        pipelineLayout,
        VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT,
        0,
        sizeof(SimplePushConstantData),
        &push);
    obj.model->bind(commandBuffer);
    obj.model->draw(commandBuffer);
  }
}
}  // namespace lve