freedreno-triangle/triangle.cc

#include <png.h>
#include <vulkan/vulkan.h>

#include <iostream>
#include <string>
#include <vector>

const uint32_t kWidth = 16;
const uint32_t kHeight = 16;

#define ERROR(message) \
    std::cerr << message << std::endl; \
    std::exit(EXIT_FAILURE)

VkInstance CreateVkInstance() {
  VkApplicationInfo app_info = {};
  app_info.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
  app_info.apiVersion = VK_API_VERSION_1_1;

  VkInstanceCreateInfo create_info = {};
  create_info.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
  create_info.pApplicationInfo = &app_info;
  create_info.enabledExtensionCount = 0;
  create_info.ppEnabledExtensionNames = nullptr;
  create_info.enabledLayerCount = 0;
  create_info.ppEnabledLayerNames = nullptr;

  VkInstance instance;
  VkResult result = vkCreateInstance(&create_info, nullptr, &instance);
  if (result != VK_SUCCESS) {
    ERROR("Error creating VkInstance: " << result);
  }
  return instance;
}

VkPhysicalDevice ChooseVkPhysicalDevice(VkInstance instance) {
  uint32_t device_count = 0;
  VkResult result = vkEnumeratePhysicalDevices(instance, &device_count, nullptr);
  if (result != VK_SUCCESS) {
    ERROR("Error enumerating VkPhysicalDevices: " << result);
  }
  if (device_count == 0) {
    ERROR("No available VkPhysicalDevices");
  }

  std::vector<VkPhysicalDevice> devices(device_count);
  result = vkEnumeratePhysicalDevices(instance, &device_count, devices.data());
  if (result != VK_SUCCESS) {
    ERROR("Error fetching VkPhysicalDevices: " << result);
  }

  std::cout << "Found " << device_count << " device(s):" << std::endl;
  VkPhysicalDevice chosen_device = VK_NULL_HANDLE;
  for (VkPhysicalDevice device : devices) {
    VkPhysicalDeviceProperties device_props;
    vkGetPhysicalDeviceProperties(device, &device_props);
    std::cout << "\t- " << device_props.deviceName << " [V: " <<
        VK_VERSION_MAJOR(device_props.apiVersion) << "." <<
        VK_VERSION_MINOR(device_props.apiVersion) << "." <<
        VK_VERSION_PATCH(device_props.apiVersion) << "]" << std::endl;
    // Currently, any device with Vulkan API version 1.1 is fine.
    if (chosen_device == VK_NULL_HANDLE && device_props.apiVersion >= VK_API_VERSION_1_1) {
      chosen_device = device;
    }
  }

  if (chosen_device == VK_NULL_HANDLE) {
    ERROR("Unable to find suitable VkPhysicalDevice");
  }
  return chosen_device;
}

uint32_t ChooseDeviceQueueFamilyIndex(VkPhysicalDevice physical_device) {
  uint32_t props_count;
  vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &props_count, nullptr);
  std::vector<VkQueueFamilyProperties> props(props_count);
  vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &props_count, props.data());

  // Simply choose the first graphics queue.
  for (size_t i = 0; i < props_count; i++) {
    const VkQueueFamilyProperties& prop = props[i];
    if ((prop.queueFlags & VK_QUEUE_GRAPHICS_BIT) && prop.queueCount > 0) {
      return i;
    }
  }

  ERROR("Unable to find suitable queue family");
}

VkDevice CreateVkDevice(VkPhysicalDevice physical_device, uint32_t device_queue_family_index) {
  VkDeviceQueueCreateInfo queue_create_info = {};
  queue_create_info.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
  queue_create_info.queueFamilyIndex = device_queue_family_index;
  queue_create_info.queueCount = 1;
  float queue_priority = 1.0f;
  queue_create_info.pQueuePriorities = &queue_priority;

  VkDeviceCreateInfo device_create_info = {};
  device_create_info.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
  device_create_info.queueCreateInfoCount = 1;
  device_create_info.pQueueCreateInfos = &queue_create_info;
  // Let's not use any device extensions for now.
  device_create_info.enabledExtensionCount = 0;
  device_create_info.ppEnabledExtensionNames = nullptr;

  VkDevice device;
  VkResult result = vkCreateDevice(physical_device, &device_create_info, nullptr, &device);
  if (result != VK_SUCCESS) {
    ERROR("Unable to create logical device");
  }
  return device;
}

int main() {
  VkInstance instance = CreateVkInstance();
  VkPhysicalDevice physical_device = ChooseVkPhysicalDevice(instance);
  uint32_t device_queue_family_index = ChooseDeviceQueueFamilyIndex(physical_device);
  VkDevice device = CreateVkDevice(physical_device, device_queue_family_index);

  // Example code for exporting a PNG.
  FILE *f = fopen("triangle.png", "wb");

  std::vector<uint8_t> pixels(kWidth * kHeight * 4);
  for (size_t i = 0; i < kHeight; i++) {
    for (size_t j = 0; j < kWidth; j++) {
      uint32_t base_index = (i * kWidth * 4) + (j * 4);
      pixels[base_index] = 255;
      pixels[base_index + 1] = 255;
      pixels[base_index + 2] = 0;
      pixels[base_index + 3] = 255;
    }
  }

  png_image image_info = {};
  image_info.version = PNG_IMAGE_VERSION;
  image_info.width = kWidth;
  image_info.height = kHeight;
  image_info.format = PNG_FORMAT_RGBA;
  if (png_image_write_to_stdio(&image_info, f, 0, pixels.data(), kWidth * 4, nullptr) == 0) {
    ERROR("Error writing PNG: " << image_info.message);
  }

  fclose(f);

  return EXIT_SUCCESS;
}