#include "tr_local.h"

#include "vk_utils.h"
#include "vk_allocator.h"
#include "vk_resource_manager.h"

#include "vk_demo.h"

#include <chrono>

const int VERTEX_CHUNK_SIZE = 512 * 1024;

const int XYZ_SIZE      = 4 * VERTEX_CHUNK_SIZE;
const int COLOR_SIZE    = 1 * VERTEX_CHUNK_SIZE;
const int ST0_SIZE      = 2 * VERTEX_CHUNK_SIZE;
const int ST1_SIZE      = 2 * VERTEX_CHUNK_SIZE;

const int XYZ_OFFSET    = 0;
const int COLOR_OFFSET  = XYZ_OFFSET + XYZ_SIZE;
const int ST0_OFFSET    = COLOR_OFFSET + COLOR_SIZE;
const int ST1_OFFSET    = ST0_OFFSET + ST0_SIZE;

static const int VERTEX_BUFFER_SIZE = XYZ_SIZE + COLOR_SIZE + ST0_SIZE + ST1_SIZE;
static const int INDEX_BUFFER_SIZE = 2 * 1024 * 1024;

static const std::vector<const char*> instance_extensions = {
    VK_KHR_SURFACE_EXTENSION_NAME,
    VK_KHR_WIN32_SURFACE_EXTENSION_NAME
};

static const std::vector<const char*> device_extensions = {
    VK_KHR_SWAPCHAIN_EXTENSION_NAME
};

static bool is_extension_available(const std::vector<VkExtensionProperties>& properties, const char* extension_name) {
    for (const auto& property : properties) {
        if (strcmp(property.extensionName, extension_name) == 0)
            return true;
    }
    return false;
}

static VkFormat find_format_with_features(VkPhysicalDevice physical_device, const std::vector<VkFormat>& candidates, VkImageTiling tiling, VkFormatFeatureFlags features) {
    for (VkFormat format : candidates) {
        VkFormatProperties properties;
        vkGetPhysicalDeviceFormatProperties(physical_device, format, &properties);

        if (tiling == VK_IMAGE_TILING_LINEAR && (properties.linearTilingFeatures & features) == features)
            return format;
        if (tiling == VK_IMAGE_TILING_OPTIMAL && (properties.optimalTilingFeatures & features) == features)
            return format;
    }
    error("failed to find format with requested features");
    return VK_FORMAT_UNDEFINED; // never get here
}

VkFormat find_depth_format(VkPhysicalDevice physical_device) {
    return find_format_with_features(physical_device, {VK_FORMAT_D32_SFLOAT, VK_FORMAT_D32_SFLOAT_S8_UINT, VK_FORMAT_D24_UNORM_S8_UINT},
        VK_IMAGE_TILING_OPTIMAL, VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT);
}

static uint32_t select_queue_family(VkPhysicalDevice physical_device, VkSurfaceKHR surface) {
    uint32_t queue_family_count;
    vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &queue_family_count, nullptr);

    std::vector<VkQueueFamilyProperties> queue_families(queue_family_count);
    vkGetPhysicalDeviceQueueFamilyProperties(physical_device, &queue_family_count, queue_families.data());

    // select queue family with presentation and graphics support
    for (uint32_t i = 0; i < queue_family_count; i++) {
        VkBool32 presentation_supported;
        auto result = vkGetPhysicalDeviceSurfaceSupportKHR(physical_device, i, surface, &presentation_supported);
        check_vk_result(result, "vkGetPhysicalDeviceSurfaceSupportKHR");

        if (presentation_supported && (queue_families[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) != 0)
            return i;
    }
    error("failed to find queue family");
    return -1;
}

static VkInstance create_instance() {
    uint32_t count = 0;
    VkResult result = vkEnumerateInstanceExtensionProperties(nullptr, &count, nullptr);
    check_vk_result(result, "vkEnumerateInstanceExtensionProperties");

    std::vector<VkExtensionProperties> extension_properties(count);
    result = vkEnumerateInstanceExtensionProperties(nullptr, &count, extension_properties.data());
    check_vk_result(result, "vkEnumerateInstanceExtensionProperties");

    for (auto name : instance_extensions) {
        if (!is_extension_available(extension_properties, name))
            error(std::string("required instance extension is not available: ") + name);
    }

    VkInstanceCreateInfo desc;
    desc.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
    desc.pNext = nullptr;
    desc.flags = 0;
    desc.pApplicationInfo = nullptr;
    desc.enabledLayerCount = 0;
    desc.ppEnabledLayerNames = nullptr;
    desc.enabledExtensionCount = static_cast<uint32_t>(instance_extensions.size());
    desc.ppEnabledExtensionNames = instance_extensions.data();

    VkInstance instance;
    result = vkCreateInstance(&desc, nullptr, &instance);
    check_vk_result(result, "vkCreateInstance");
    return instance;
}

static VkPhysicalDevice select_physical_device(VkInstance instance) {
    uint32_t count;
    VkResult result = vkEnumeratePhysicalDevices(instance, &count, nullptr);
    check_vk_result(result, "vkEnumeratePhysicalDevices");

    if (count == 0)
        error("no physical device found");

    std::vector<VkPhysicalDevice> physical_devices(count);
    result = vkEnumeratePhysicalDevices(instance, &count, physical_devices.data());
    check_vk_result(result, "vkEnumeratePhysicalDevices");
    return physical_devices[0]; // just get the first one
}

static VkSurfaceKHR create_surface(VkInstance instance, HWND hwnd) {
    VkWin32SurfaceCreateInfoKHR desc;
    desc.sType = VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR;
    desc.pNext = nullptr;
    desc.flags = 0;
    desc.hinstance = ::GetModuleHandle(nullptr);
    desc.hwnd = hwnd;

    VkSurfaceKHR surface;
    VkResult result = vkCreateWin32SurfaceKHR(instance, &desc, nullptr, &surface);
    check_vk_result(result, "vkCreateWin32SurfaceKHR");
    return surface;
}

static VkDevice create_device(VkPhysicalDevice physical_device, uint32_t queue_family_index) {
    uint32_t count = 0;
    VkResult result = vkEnumerateDeviceExtensionProperties(physical_device, nullptr, &count, nullptr);
    check_vk_result(result, "vkEnumerateDeviceExtensionProperties");

    std::vector<VkExtensionProperties> extension_properties(count);
    result = vkEnumerateDeviceExtensionProperties(physical_device, nullptr, &count, extension_properties.data());
    check_vk_result(result, "vkEnumerateDeviceExtensionProperties");

    for (auto name : device_extensions) {
        if (!is_extension_available(extension_properties, name))
            error(std::string("required device extension is not available: ") + name);
    }

    const float priority = 1.0;
    VkDeviceQueueCreateInfo queue_desc;
    queue_desc.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
    queue_desc.pNext = nullptr;
    queue_desc.flags = 0;
    queue_desc.queueFamilyIndex = queue_family_index;
    queue_desc.queueCount = 1;
    queue_desc.pQueuePriorities = &priority;

    VkDeviceCreateInfo device_desc;
    device_desc.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
    device_desc.pNext = nullptr;
    device_desc.flags = 0;
    device_desc.queueCreateInfoCount = 1;
    device_desc.pQueueCreateInfos = &queue_desc;
    device_desc.enabledLayerCount = 0;
    device_desc.ppEnabledLayerNames = nullptr;
    device_desc.enabledExtensionCount = static_cast<uint32_t>(device_extensions.size());
    device_desc.ppEnabledExtensionNames = device_extensions.data();
    device_desc.pEnabledFeatures = nullptr;

    VkDevice device;
    result = vkCreateDevice(physical_device, &device_desc, nullptr, &device);
    check_vk_result(result, "vkCreateDevice");
    return device;
}

static VkSurfaceFormatKHR select_surface_format(VkPhysicalDevice physical_device, VkSurfaceKHR surface) {
    uint32_t format_count;
    VkResult result = vkGetPhysicalDeviceSurfaceFormatsKHR(physical_device, surface, &format_count, nullptr);
    check_vk_result(result, "vkGetPhysicalDeviceSurfaceFormatsKHR");
    assert(format_count > 0);

    std::vector<VkSurfaceFormatKHR> candidates(format_count);
    result = vkGetPhysicalDeviceSurfaceFormatsKHR(physical_device, surface, &format_count, candidates.data());
    check_vk_result(result, "vkGetPhysicalDeviceSurfaceFormatsKHR");

    // special case that means we can choose any format
    if (candidates.size() == 1 && candidates[0].format == VK_FORMAT_UNDEFINED) {
        VkSurfaceFormatKHR surface_format;
        surface_format.format = VK_FORMAT_R8G8B8A8_UNORM;
        surface_format.colorSpace = VK_COLORSPACE_SRGB_NONLINEAR_KHR;
        return surface_format;
    }
    return candidates[0];
}

static VkSwapchainKHR create_swapchain(VkPhysicalDevice physical_device, VkDevice device, VkSurfaceKHR surface, VkSurfaceFormatKHR surface_format) {
    VkSurfaceCapabilitiesKHR surface_caps;
    VkResult result = vkGetPhysicalDeviceSurfaceCapabilitiesKHR(physical_device, surface, &surface_caps);
    check_vk_result(result, "vkGetPhysicalDeviceSurfaceCapabilitiesKHR");

    VkExtent2D image_extent = surface_caps.currentExtent;
    if (image_extent.width == 0xffffffff && image_extent.height == 0xffffffff) {
        image_extent.width = std::min(surface_caps.maxImageExtent.width, std::max(surface_caps.minImageExtent.width, 640u));
        image_extent.height = std::min(surface_caps.maxImageExtent.height, std::max(surface_caps.minImageExtent.height, 480u));
    }

    // transfer destination usage is required by image clear operations
    if ((surface_caps.supportedUsageFlags & VK_IMAGE_USAGE_TRANSFER_DST_BIT) == 0)
        error("VK_IMAGE_USAGE_TRANSFER_DST_BIT is not supported by the swapchain");
    VkImageUsageFlags image_usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;

    // determine present mode and swapchain image count
    uint32_t present_mode_count;
    result = vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, surface, &present_mode_count, nullptr);
    check_vk_result(result, "vkGetPhysicalDeviceSurfacePresentModesKHR");
    std::vector<VkPresentModeKHR> present_modes(present_mode_count);
    result = vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, surface, &present_mode_count, present_modes.data());
    check_vk_result(result, "vkGetPhysicalDeviceSurfacePresentModesKHR");

    VkPresentModeKHR present_mode;
    uint32_t image_count;

    auto it = std::find(present_modes.cbegin(), present_modes.cend(), VK_PRESENT_MODE_MAILBOX_KHR);
    if (it != present_modes.cend()) {
        present_mode = VK_PRESENT_MODE_MAILBOX_KHR;
        image_count = std::max(3u, surface_caps.minImageCount);
        if (surface_caps.maxImageCount > 0) {
            image_count = std::min(image_count, surface_caps.maxImageCount);
        }
    }
    else {
        present_mode = VK_PRESENT_MODE_FIFO_KHR;
        image_count = surface_caps.minImageCount;
    }

    // create swap chain
    VkSwapchainCreateInfoKHR desc;
    desc.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR;
    desc.pNext = nullptr;
    desc.flags = 0;
    desc.surface = surface;
    desc.minImageCount = image_count;
    desc.imageFormat = surface_format.format;
    desc.imageColorSpace = surface_format.colorSpace;
    desc.imageExtent = image_extent;
    desc.imageArrayLayers = 1;
    desc.imageUsage = image_usage;
    desc.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
    desc.queueFamilyIndexCount = 0;
    desc.pQueueFamilyIndices = nullptr;
    desc.preTransform = surface_caps.currentTransform;
    desc.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
    desc.presentMode = present_mode;
    desc.clipped = VK_TRUE;
    desc.oldSwapchain = VK_NULL_HANDLE;

    VkSwapchainKHR swapchain;
    result = vkCreateSwapchainKHR(device, &desc, nullptr, &swapchain);
    check_vk_result(result, "vkCreateSwapchainKHR");
    return swapchain;
}

static VkRenderPass create_render_pass(VkDevice device, VkFormat color_format, VkFormat depth_format) {
    VkAttachmentDescription attachments[2];
    attachments[0].flags = 0;
	attachments[0].format = color_format;
    attachments[0].samples = VK_SAMPLE_COUNT_1_BIT;
	attachments[0].loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
    attachments[0].storeOp = VK_ATTACHMENT_STORE_OP_STORE;
    attachments[0].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
    attachments[0].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
    attachments[0].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
    attachments[0].finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;

    attachments[1].flags = 0;
	attachments[1].format = depth_format;
    attachments[1].samples = VK_SAMPLE_COUNT_1_BIT;
    attachments[1].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
    attachments[1].storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
    attachments[1].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
    attachments[1].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
    attachments[1].initialLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
    attachments[1].finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

    VkAttachmentReference color_attachment_ref;
    color_attachment_ref.attachment = 0;
    color_attachment_ref.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

    VkAttachmentReference depth_attachment_ref;
    depth_attachment_ref.attachment = 1;
    depth_attachment_ref.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

    VkSubpassDescription subpass;
    subpass.flags = 0;
    subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
    subpass.inputAttachmentCount = 0;
    subpass.pInputAttachments = nullptr;
    subpass.colorAttachmentCount = 1;
    subpass.pColorAttachments = &color_attachment_ref;
    subpass.pResolveAttachments = nullptr;
    subpass.pDepthStencilAttachment = &depth_attachment_ref;
    subpass.preserveAttachmentCount = 0;
    subpass.pPreserveAttachments = nullptr;

    VkRenderPassCreateInfo desc;
    desc.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
    desc.pNext = nullptr;
    desc.flags = 0;
	desc.attachmentCount = sizeof(attachments) / sizeof(attachments[0]);
	desc.pAttachments = attachments;
    desc.subpassCount = 1;
    desc.pSubpasses = &subpass;
    desc.dependencyCount = 0;
    desc.pDependencies = nullptr;

    VkRenderPass render_pass;
    VkResult result = vkCreateRenderPass(device, &desc, nullptr, &render_pass);
    check_vk_result(result, "vkCreateRenderPass");
    return render_pass;
}

bool vk_initialize(HWND hwnd) {
    try {
        auto& g = vk;

        g.instance = create_instance();
        g.physical_device = select_physical_device(g.instance);
        g.surface = create_surface(g.instance, hwnd);
        g.surface_format = select_surface_format(g.physical_device, g.surface);

        g.queue_family_index = select_queue_family(g.physical_device, g.surface);
        g.device = create_device(g.physical_device, g.queue_family_index);
        vkGetDeviceQueue(g.device, g.queue_family_index, 0, &g.queue);

        g.swapchain = create_swapchain(g.physical_device, g.device, g.surface, g.surface_format);

        VkResult result = vkGetSwapchainImagesKHR(g.device, g.swapchain, &vk.swapchain_image_count, nullptr);
        check_vk_result(result, "vkGetSwapchainImagesKHR");

        if (vk.swapchain_image_count > MAX_SWAPCHAIN_IMAGES)
            ri.Error( ERR_FATAL, "initialize_vulkan: swapchain image count (%d) exceeded limit (%d)", vk.swapchain_image_count, MAX_SWAPCHAIN_IMAGES );

        result = vkGetSwapchainImagesKHR(g.device, g.swapchain, &vk.swapchain_image_count, g.swapchain_images);
        check_vk_result(result, "vkGetSwapchainImagesKHR");

        for (std::size_t i = 0; i < vk.swapchain_image_count; i++) {
            VkImageViewCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.image = g.swapchain_images[i];
            desc.viewType = VK_IMAGE_VIEW_TYPE_2D;
            desc.format = g.surface_format.format;
            desc.components.r = VK_COMPONENT_SWIZZLE_IDENTITY;
            desc.components.g = VK_COMPONENT_SWIZZLE_IDENTITY;
            desc.components.b = VK_COMPONENT_SWIZZLE_IDENTITY;
            desc.components.a = VK_COMPONENT_SWIZZLE_IDENTITY;
            desc.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
            desc.subresourceRange.baseMipLevel = 0;
            desc.subresourceRange.levelCount = 1;
            desc.subresourceRange.baseArrayLayer = 0;
            desc.subresourceRange.layerCount = 1;
            result = vkCreateImageView(g.device, &desc, nullptr, &g.swapchain_image_views[i]);
            check_vk_result(result, "vkCreateImageView");
        }

        {
            VkCommandPoolCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = VK_COMMAND_POOL_CREATE_TRANSIENT_BIT | VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;
            desc.queueFamilyIndex = vk.queue_family_index;

            result = vkCreateCommandPool(g.device, &desc, nullptr, &vk.command_pool);
            check_vk_result(result, "vkCreateCommandPool");
        }

        {
            VkCommandBufferAllocateInfo alloc_info;
            alloc_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
            alloc_info.pNext = nullptr;
            alloc_info.commandPool = vk.command_pool;
            alloc_info.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
            alloc_info.commandBufferCount = 1;
            result = vkAllocateCommandBuffers(vk.device, &alloc_info, &g.command_buffer);
            check_vk_result(result, "vkAllocateCommandBuffers");
        }

        get_allocator()->initialize(vk.physical_device, vk.device);
        get_resource_manager()->initialize(vk.device);

        {
            VkFormat depth_format = find_depth_format(vk.physical_device);
            vk.depth_image = create_depth_attachment_image(glConfig.vidWidth, glConfig.vidHeight, depth_format);
            vk.depth_image_view = create_image_view(vk.depth_image, depth_format, VK_IMAGE_ASPECT_DEPTH_BIT);

            record_and_run_commands(vk.command_pool, vk.queue, [&depth_format](VkCommandBuffer command_buffer) {
                record_image_layout_transition(command_buffer, vk.depth_image, depth_format, 0, VK_IMAGE_LAYOUT_UNDEFINED,
                    VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT, VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL);
            });
        }

		VkFormat depth_format = find_depth_format(vk.physical_device);

		vk.render_pass = create_render_pass(vk.device, vk.surface_format.format, depth_format);

        {
            std::array<VkImageView, 2> attachments = {VK_NULL_HANDLE, vk.depth_image_view};

            VkFramebufferCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.renderPass = vk.render_pass;
            desc.attachmentCount = static_cast<uint32_t>(attachments.size());
            desc.pAttachments = attachments.data();
            desc.width = glConfig.vidWidth;
            desc.height = glConfig.vidHeight;
            desc.layers = 1;

            for (uint32_t i = 0; i < vk.swapchain_image_count; i++) {
                attachments[0] = vk.swapchain_image_views[i]; // set color attachment
                VkResult result = vkCreateFramebuffer(vk.device, &desc, nullptr, &vk.framebuffers[i]);
                check_vk_result(result, "vkCreateFramebuffer");
            }
        }

        //
        // Descriptor pool.
        //
        {
            VkDescriptorPoolSize pool_size;
            pool_size.type = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
            pool_size.descriptorCount = MAX_DRAWIMAGES;

            VkDescriptorPoolCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.maxSets = MAX_DRAWIMAGES;
            desc.poolSizeCount = 1;
            desc.pPoolSizes = &pool_size;

            VkResult result = vkCreateDescriptorPool(vk.device, &desc, nullptr, &vk.descriptor_pool);
            check_vk_result(result, "vkCreateDescriptorPool");
        }

        //
        // Descriptor set layout.
        //
        {
            VkDescriptorSetLayoutBinding descriptor_binding;
            descriptor_binding.binding = 0;
            descriptor_binding.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
            descriptor_binding.descriptorCount = 1;
            descriptor_binding.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
            descriptor_binding.pImmutableSamplers = nullptr;

            VkDescriptorSetLayoutCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.bindingCount = 1;
            desc.pBindings = &descriptor_binding;

            VkResult result = vkCreateDescriptorSetLayout(vk.device, &desc, nullptr, &vk.set_layout);
            check_vk_result(result, "vkCreateDescriptorSetLayout");
        }

        //
        // Pipeline layout.
        //
        {
            VkPushConstantRange push_range;
            push_range.stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
            push_range.offset = 0;
            push_range.size = 64; // sizeof(float[16])

            VkDescriptorSetLayout set_layouts[2] = {vk.set_layout, vk.set_layout};

            VkPipelineLayoutCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.setLayoutCount = 2;
            desc.pSetLayouts = set_layouts;
            desc.pushConstantRangeCount = 1;
            desc.pPushConstantRanges = &push_range;

            VkResult result = vkCreatePipelineLayout(vk.device, &desc, nullptr, &vk.pipeline_layout);
            check_vk_result(result, "vkCreatePipelineLayout");
        }

        //
        // Create geometry buffers.
        //
        {
            VkBufferCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.size = VERTEX_BUFFER_SIZE;
            desc.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
            desc.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
            desc.queueFamilyIndexCount = 0;
            desc.pQueueFamilyIndices = nullptr;

            VkResult result = vkCreateBuffer(vk.device, &desc, nullptr, &vk.vertex_buffer);
            check_vk_result(result, "vkCreateBuffer");

            vk.vertex_buffer_memory = get_allocator()->allocate_staging_memory(vk.vertex_buffer);
            result = vkBindBufferMemory(vk.device, vk.vertex_buffer, vk.vertex_buffer_memory, 0);
            check_vk_result(result, "vkBindBufferMemory");

            void* data;
            result = vkMapMemory(vk.device, vk.vertex_buffer_memory, 0, VERTEX_BUFFER_SIZE, 0, &data);
            check_vk_result(result, "vkMapMemory");
            vk.vertex_buffer_ptr = (byte*)data;
        }
        {
            VkBufferCreateInfo desc;
            desc.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
            desc.pNext = nullptr;
            desc.flags = 0;
            desc.size = INDEX_BUFFER_SIZE;
            desc.usage = VK_BUFFER_USAGE_INDEX_BUFFER_BIT;
            desc.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
            desc.queueFamilyIndexCount = 0;
            desc.pQueueFamilyIndices = nullptr;

            VkResult result = vkCreateBuffer(vk.device, &desc, nullptr, &vk.index_buffer);
            check_vk_result(result, "vkCreateBuffer");

            vk.index_buffer_memory = get_allocator()->allocate_staging_memory(vk.index_buffer);
            result = vkBindBufferMemory(vk.device, vk.index_buffer, vk.index_buffer_memory, 0);
            check_vk_result(result, "vkBindBufferMemory");

            void* data;
            result = vkMapMemory(vk.device, vk.index_buffer_memory, 0, INDEX_BUFFER_SIZE, 0, &data);
            check_vk_result(result, "vkMapMemory");
            vk.index_buffer_ptr = (byte*)data;
        }

    } catch (const std::exception&) {
        return false;
    }
    return true;
}

void vk_deinitialize() {
    auto& g = vk;

    get_resource_manager()->release_resources();
    get_allocator()->deallocate_all();

    vkDestroyFence(vk.device, vulkan_demo->rendering_finished_fence, nullptr);
    vkDestroyImage(vk.device, vk.depth_image, nullptr);
    vkDestroyImageView(vk.device, vk.depth_image_view, nullptr);

    for (uint32_t i = 0; i < vk.swapchain_image_count; i++) {
        vkDestroyFramebuffer(vk.device, vk.framebuffers[i], nullptr);
    }

    vkDestroyRenderPass(vk.device, vk.render_pass, nullptr);

    vkDestroyCommandPool(g.device, g.command_pool, nullptr);

    for (uint32_t i = 0; i < g.swapchain_image_count; i++) {
        vkDestroyImageView(g.device, g.swapchain_image_views[i], nullptr);
    }

    vkDestroyDescriptorPool(vk.device, vk.descriptor_pool, nullptr);
    vkDestroyDescriptorSetLayout(vk.device, vk.set_layout, nullptr);
    vkDestroyPipelineLayout(vk.device, vk.pipeline_layout, nullptr);
    vkDestroyBuffer(vk.device, vk.vertex_buffer, nullptr);
    vkDestroyBuffer(vk.device, vk.index_buffer, nullptr);

    vkDestroySwapchainKHR(g.device, g.swapchain, nullptr);
    vkDestroyDevice(g.device, nullptr);
    vkDestroySurfaceKHR(g.instance, g.surface, nullptr);
    vkDestroyInstance(g.instance, nullptr);

    g = Vulkan_Instance();
}

VkImage vk_create_cinematic_image(int width, int height, Vk_Staging_Buffer& staging_buffer) {
    VkBufferCreateInfo buffer_desc;
    buffer_desc.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
    buffer_desc.pNext = nullptr;
    buffer_desc.flags = 0;
    buffer_desc.size = width * height * 4;
    buffer_desc.usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT;
    buffer_desc.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
    buffer_desc.queueFamilyIndexCount = 0;
    buffer_desc.pQueueFamilyIndices = nullptr;

    VkBuffer buffer;
    VkResult result = vkCreateBuffer(vk.device, &buffer_desc, nullptr, &buffer);
    check_vk_result(result, "vkCreateBuffer");

    VkDeviceMemory buffer_memory = get_allocator()->allocate_staging_memory(buffer);
    result = vkBindBufferMemory(vk.device, buffer, buffer_memory, 0);
    check_vk_result(result, "vkBindBufferMemory");

    VkImageCreateInfo image_desc;
    image_desc.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
    image_desc.pNext = nullptr;
    image_desc.flags = 0;
    image_desc.imageType = VK_IMAGE_TYPE_2D;
    image_desc.format = VK_FORMAT_R8G8B8A8_UNORM;
    image_desc.extent.width = width;
    image_desc.extent.height = height;
    image_desc.extent.depth = 1;
    image_desc.mipLevels = 1;
    image_desc.arrayLayers = 1;
    image_desc.samples = VK_SAMPLE_COUNT_1_BIT;
    image_desc.tiling = VK_IMAGE_TILING_OPTIMAL;
    image_desc.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
    image_desc.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
    image_desc.queueFamilyIndexCount = 0;
    image_desc.pQueueFamilyIndices = nullptr;
    image_desc.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;

    VkImage image;
    result = vkCreateImage(vk.device, &image_desc, nullptr, &image);
    check_vk_result(result, "vkCreateImage");

    VkDeviceMemory image_memory = get_allocator()->allocate_memory(image);
    result = vkBindImageMemory(vk.device, image, image_memory, 0);
    check_vk_result(result, "vkBindImageMemory");

    staging_buffer.handle = buffer;
    staging_buffer.memory = buffer_memory;
    staging_buffer.offset = 0;
    staging_buffer.size = width * height * 4;
    return image;
}

void vk_update_cinematic_image(VkImage image, const Vk_Staging_Buffer& staging_buffer, int width, int height, const uint8_t* rgba_pixels) {
    void* buffer_data;
    VkResult result = vkMapMemory(vk.device, staging_buffer.memory, staging_buffer.offset, staging_buffer.size, 0, &buffer_data);
    check_vk_result(result, "vkMapMemory");
    memcpy(buffer_data, rgba_pixels, staging_buffer.size);
    vkUnmapMemory(vk.device, staging_buffer.memory);

    record_and_run_commands(vk.command_pool, vk.queue,
        [&image, &staging_buffer, &width, &height](VkCommandBuffer command_buffer) {

        record_image_layout_transition(command_buffer, image, VK_FORMAT_R8G8B8A8_UNORM,
            0, VK_IMAGE_LAYOUT_UNDEFINED, VK_ACCESS_TRANSFER_WRITE_BIT, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL);

        VkBufferImageCopy region;
        region.bufferOffset = 0;
        region.bufferRowLength = 0;
        region.bufferImageHeight = 0;
        region.imageSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        region.imageSubresource.mipLevel = 0;
        region.imageSubresource.baseArrayLayer = 0;
        region.imageSubresource.layerCount = 1;
        region.imageOffset = VkOffset3D{ 0, 0, 0 };
        region.imageExtent = VkExtent3D{ (uint32_t)width, (uint32_t)height, 1 };

        vkCmdCopyBufferToImage(command_buffer, staging_buffer.handle, image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &region);

        record_image_layout_transition(command_buffer, image, VK_FORMAT_R8G8B8A8_UNORM,
            VK_ACCESS_TRANSFER_WRITE_BIT, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, VK_ACCESS_SHADER_READ_BIT, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
    });
}

static VkPipeline create_pipeline(const Vk_Pipeline_Desc& desc) {
    Shader_Module single_texture_vs(single_texture_vert_spv, single_texture_vert_spv_size);
    Shader_Module single_texture_fs(single_texture_frag_spv, single_texture_frag_spv_size);

    Shader_Module multi_texture_vs(multi_texture_vert_spv, multi_texture_vert_spv_size);
    Shader_Module multi_texture_mul_fs(multi_texture_mul_frag_spv, multi_texture_mul_frag_spv_size);
    Shader_Module multi_texture_add_fs(multi_texture_add_frag_spv, multi_texture_add_frag_spv_size);

    auto get_shader_stage_desc = [](VkShaderStageFlagBits stage, VkShaderModule shader_module, const char* entry) {
        VkPipelineShaderStageCreateInfo desc;
        desc.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
        desc.pNext = nullptr;
        desc.flags = 0;
        desc.stage = stage;
        desc.module = shader_module;
        desc.pName = entry;
        desc.pSpecializationInfo = nullptr;
        return desc;
    };

    struct Specialization_Data {
        int32_t alpha_test_func;
    } specialization_data;

    if ((desc.state_bits & GLS_ATEST_BITS) == 0)
        specialization_data.alpha_test_func = 0;
    else if (desc.state_bits & GLS_ATEST_GT_0)
        specialization_data.alpha_test_func = 1;
    else if (desc.state_bits & GLS_ATEST_LT_80)
        specialization_data.alpha_test_func = 2;
    else if (desc.state_bits & GLS_ATEST_GE_80)
        specialization_data.alpha_test_func = 3;
    else
        ri.Error(ERR_DROP, "create_pipeline: invalid alpha test state bits\n");

    std::array<VkSpecializationMapEntry, 1> specialization_entries;
    specialization_entries[0].constantID = 0;
    specialization_entries[0].offset = offsetof(struct Specialization_Data, alpha_test_func);
    specialization_entries[0].size = sizeof(int32_t);

    VkSpecializationInfo specialization_info;
    specialization_info.mapEntryCount = uint32_t(specialization_entries.size());
    specialization_info.pMapEntries = specialization_entries.data();
    specialization_info.dataSize = sizeof(Specialization_Data);
    specialization_info.pData = &specialization_data;

    std::vector<VkPipelineShaderStageCreateInfo> shader_stages_state;

    if (desc.shader_type == Vk_Shader_Type::single_texture) {
        shader_stages_state.push_back(get_shader_stage_desc(VK_SHADER_STAGE_VERTEX_BIT, single_texture_vs.handle, "main"));
        shader_stages_state.push_back(get_shader_stage_desc(VK_SHADER_STAGE_FRAGMENT_BIT, single_texture_fs.handle, "main"));
    } else if (desc.shader_type == Vk_Shader_Type::multi_texture_mul) {
        shader_stages_state.push_back(get_shader_stage_desc(VK_SHADER_STAGE_VERTEX_BIT, multi_texture_vs.handle, "main"));
        shader_stages_state.push_back(get_shader_stage_desc(VK_SHADER_STAGE_FRAGMENT_BIT, multi_texture_mul_fs.handle, "main"));
    } else if (desc.shader_type == Vk_Shader_Type::multi_texture_add) {
        shader_stages_state.push_back(get_shader_stage_desc(VK_SHADER_STAGE_VERTEX_BIT, multi_texture_vs.handle, "main"));
        shader_stages_state.push_back(get_shader_stage_desc(VK_SHADER_STAGE_FRAGMENT_BIT, multi_texture_add_fs.handle, "main"));
    }

    if (desc.state_bits & GLS_ATEST_BITS)
        shader_stages_state.back().pSpecializationInfo = &specialization_info;

    //
    // Vertex input
    //
    VkVertexInputBindingDescription bindings[4];
    // xyz array
    bindings[0].binding = 0;
    bindings[0].stride = sizeof(vec4_t);
    bindings[0].inputRate = VK_VERTEX_INPUT_RATE_VERTEX;

    // color array
    bindings[1].binding = 1;
    bindings[1].stride = sizeof(color4ub_t);
    bindings[1].inputRate = VK_VERTEX_INPUT_RATE_VERTEX;

    // st0 array
    bindings[2].binding = 2;
    bindings[2].stride = sizeof(vec2_t);
    bindings[2].inputRate = VK_VERTEX_INPUT_RATE_VERTEX;

    // st1 array
    bindings[3].binding = 3;
    bindings[3].stride = sizeof(vec2_t);
    bindings[3].inputRate = VK_VERTEX_INPUT_RATE_VERTEX;

    VkVertexInputAttributeDescription attribs[4];
    // xyz
    attribs[0].location = 0;
    attribs[0].binding = 0;
    attribs[0].format = VK_FORMAT_R32G32B32A32_SFLOAT;
    attribs[0].offset = 0;

    // color
    attribs[1].location = 1;
    attribs[1].binding = 1;
    attribs[1].format = VK_FORMAT_R8G8B8A8_UNORM;
    attribs[1].offset = 0;

    // st0
    attribs[2].location = 2;
    attribs[2].binding = 2;
    attribs[2].format = VK_FORMAT_R32G32_SFLOAT;
    attribs[2].offset = 0;

    // st1
    attribs[3].location = 3;
    attribs[3].binding = 3;
    attribs[3].format = VK_FORMAT_R32G32_SFLOAT;
    attribs[3].offset = 0;

    VkPipelineVertexInputStateCreateInfo vertex_input_state;
    vertex_input_state.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
    vertex_input_state.pNext = nullptr;
    vertex_input_state.flags = 0;
    vertex_input_state.vertexBindingDescriptionCount = (desc.shader_type == Vk_Shader_Type::single_texture) ? 3 : 4;
    vertex_input_state.pVertexBindingDescriptions = bindings;
    vertex_input_state.vertexAttributeDescriptionCount = (desc.shader_type == Vk_Shader_Type::single_texture) ? 3 : 4;
    vertex_input_state.pVertexAttributeDescriptions = attribs;

    //
    // Primitive assembly.
    //
    VkPipelineInputAssemblyStateCreateInfo input_assembly_state;
    input_assembly_state.sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO;
    input_assembly_state.pNext = nullptr;
    input_assembly_state.flags = 0;
    input_assembly_state.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
    input_assembly_state.primitiveRestartEnable = VK_FALSE;

    //
    // Viewport.
    //
    VkPipelineViewportStateCreateInfo viewport_state;
    viewport_state.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
    viewport_state.pNext = nullptr;
    viewport_state.flags = 0;
    viewport_state.viewportCount = 1;
    viewport_state.pViewports = nullptr; // dynamic viewport state
    viewport_state.scissorCount = 1;
    viewport_state.pScissors = nullptr; // dynamic scissor state

    //
    // Rasterization.
    //
    VkPipelineRasterizationStateCreateInfo rasterization_state;
    rasterization_state.sType = VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO;
    rasterization_state.pNext = nullptr;
    rasterization_state.flags = 0;
    rasterization_state.depthClampEnable = VK_FALSE;
    rasterization_state.rasterizerDiscardEnable = VK_FALSE;
    rasterization_state.polygonMode = (desc.state_bits & GLS_POLYMODE_LINE) ? VK_POLYGON_MODE_LINE : VK_POLYGON_MODE_FILL;

    if (desc.face_culling == CT_TWO_SIDED)
        rasterization_state.cullMode = VK_CULL_MODE_NONE;
    else if (desc.face_culling == CT_FRONT_SIDED)
        rasterization_state.cullMode = VK_CULL_MODE_BACK_BIT;
    else if (desc.face_culling == CT_BACK_SIDED)
        rasterization_state.cullMode = VK_CULL_MODE_FRONT_BIT;
    else
        ri.Error(ERR_DROP, "create_pipeline: invalid face culling mode\n");

    rasterization_state.frontFace = VK_FRONT_FACE_CLOCKWISE; // Q3 defaults to clockwise vertex order

    rasterization_state.depthBiasEnable = desc.polygon_offset ? VK_TRUE : VK_FALSE;
    rasterization_state.depthBiasConstantFactor = 0.0f; // dynamic depth bias state
    rasterization_state.depthBiasClamp = 0.0f; // dynamic depth bias state
    rasterization_state.depthBiasSlopeFactor = 0.0f; // dynamic depth bias state
    rasterization_state.lineWidth = 1.0f;

    VkPipelineMultisampleStateCreateInfo multisample_state;
    multisample_state.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
    multisample_state.pNext = nullptr;
    multisample_state.flags = 0;
    multisample_state.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
    multisample_state.sampleShadingEnable = VK_FALSE;
    multisample_state.minSampleShading = 1.0f;
    multisample_state.pSampleMask = nullptr;
    multisample_state.alphaToCoverageEnable = VK_FALSE;
    multisample_state.alphaToOneEnable = VK_FALSE;

    VkPipelineDepthStencilStateCreateInfo depth_stencil_state;
    depth_stencil_state.sType = VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO;
    depth_stencil_state.pNext = nullptr;
    depth_stencil_state.flags = 0;
    depth_stencil_state.depthTestEnable = (desc.state_bits & GLS_DEPTHTEST_DISABLE) ? VK_FALSE : VK_TRUE;
    depth_stencil_state.depthWriteEnable = (desc.state_bits & GLS_DEPTHMASK_TRUE) ? VK_TRUE : VK_FALSE;
    depth_stencil_state.depthCompareOp = (desc.state_bits & GLS_DEPTHFUNC_EQUAL) ? VK_COMPARE_OP_EQUAL : VK_COMPARE_OP_LESS_OR_EQUAL;
    depth_stencil_state.depthBoundsTestEnable = VK_FALSE;
    depth_stencil_state.stencilTestEnable = VK_FALSE;
    depth_stencil_state.front = {};
    depth_stencil_state.back = {};
    depth_stencil_state.minDepthBounds = 0.0;
    depth_stencil_state.maxDepthBounds = 0.0;

    VkPipelineColorBlendAttachmentState attachment_blend_state = {};
    attachment_blend_state.blendEnable = (desc.state_bits & (GLS_SRCBLEND_BITS | GLS_DSTBLEND_BITS)) ? VK_TRUE : VK_FALSE;
    attachment_blend_state.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
    
    if (attachment_blend_state.blendEnable) {
        switch (desc.state_bits & GLS_SRCBLEND_BITS) {
            case GLS_SRCBLEND_ZERO:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_ZERO;
                break;
            case GLS_SRCBLEND_ONE:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_ONE;
                break;
            case GLS_SRCBLEND_DST_COLOR:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_DST_COLOR;
                break;
            case GLS_SRCBLEND_ONE_MINUS_DST_COLOR:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR;
                break;
            case GLS_SRCBLEND_SRC_ALPHA:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA;
                break;
            case GLS_SRCBLEND_ONE_MINUS_SRC_ALPHA:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
                break;
            case GLS_SRCBLEND_DST_ALPHA:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_DST_ALPHA;
                break;
            case GLS_SRCBLEND_ONE_MINUS_DST_ALPHA:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA;
                break;
            case GLS_SRCBLEND_ALPHA_SATURATE:
                attachment_blend_state.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA_SATURATE;
                break;
            default:
                ri.Error( ERR_DROP, "create_pipeline: invalid src blend state bits\n" );
                break;
        }
        switch (desc.state_bits & GLS_DSTBLEND_BITS) {
            case GLS_DSTBLEND_ZERO:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_ZERO;
                break;
            case GLS_DSTBLEND_ONE:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_ONE;
                break;
            case GLS_DSTBLEND_SRC_COLOR:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_SRC_COLOR;
                break;
            case GLS_DSTBLEND_ONE_MINUS_SRC_COLOR:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR;
                break;
            case GLS_DSTBLEND_SRC_ALPHA:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA;
                break;
            case GLS_DSTBLEND_ONE_MINUS_SRC_ALPHA:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
                break;
            case GLS_DSTBLEND_DST_ALPHA:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_DST_ALPHA;
                break;
            case GLS_DSTBLEND_ONE_MINUS_DST_ALPHA:
                attachment_blend_state.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA;
                break;
            default:
                ri.Error( ERR_DROP, "create_pipeline: invalid dst blend state bits\n" );
                break;
        }

        attachment_blend_state.srcAlphaBlendFactor = attachment_blend_state.srcColorBlendFactor;
        attachment_blend_state.dstAlphaBlendFactor = attachment_blend_state.dstColorBlendFactor;
        attachment_blend_state.colorBlendOp = VK_BLEND_OP_ADD;
        attachment_blend_state.alphaBlendOp = VK_BLEND_OP_ADD;
    }

    VkPipelineColorBlendStateCreateInfo blend_state;
    blend_state.sType = VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO;
    blend_state.pNext = nullptr;
    blend_state.flags = 0;
    blend_state.logicOpEnable = VK_FALSE;
    blend_state.logicOp = VK_LOGIC_OP_COPY;
    blend_state.attachmentCount = 1;
    blend_state.pAttachments = &attachment_blend_state;
    blend_state.blendConstants[0] = 0.0f;
    blend_state.blendConstants[1] = 0.0f;
    blend_state.blendConstants[2] = 0.0f;
    blend_state.blendConstants[3] = 0.0f;

    VkPipelineDynamicStateCreateInfo dynamic_state;
    dynamic_state.sType = VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO;
    dynamic_state.pNext = nullptr;
    dynamic_state.flags = 0;
    dynamic_state.dynamicStateCount = 3;
    VkDynamicState dynamic_state_array[3] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR, VK_DYNAMIC_STATE_DEPTH_BIAS };
    dynamic_state.pDynamicStates = dynamic_state_array;

    VkGraphicsPipelineCreateInfo create_info;
    create_info.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
    create_info.pNext = nullptr;
    create_info.flags = 0;
    create_info.stageCount = static_cast<uint32_t>(shader_stages_state.size());
    create_info.pStages = shader_stages_state.data();
    create_info.pVertexInputState = &vertex_input_state;
    create_info.pInputAssemblyState = &input_assembly_state;
    create_info.pTessellationState = nullptr;
    create_info.pViewportState = &viewport_state;
    create_info.pRasterizationState = &rasterization_state;
    create_info.pMultisampleState = &multisample_state;
    create_info.pDepthStencilState = &depth_stencil_state;
    create_info.pColorBlendState = &blend_state;
    create_info.pDynamicState = &dynamic_state;
    create_info.layout = vk.pipeline_layout;
    create_info.renderPass = vk.render_pass;
    create_info.subpass = 0;
    create_info.basePipelineHandle = VK_NULL_HANDLE;
    create_info.basePipelineIndex = -1;

    VkPipeline pipeline;
    VkResult result = vkCreateGraphicsPipelines(vk.device, VK_NULL_HANDLE, 1, &create_info, nullptr, &pipeline);
    check_vk_result(result, "vkCreateGraphicsPipelines");
    return pipeline;
}

static float pipeline_create_time;

struct Timer {
    using Clock = std::chrono::high_resolution_clock;
    using Second = std::chrono::duration<double, std::ratio<1>>;

    Clock::time_point start = Clock::now();
    double Elapsed_Seconds() const {
        const auto duration = Clock::now() - start;
        double seconds = std::chrono::duration_cast<Second>(duration).count();
        return seconds;
    }
};

VkPipeline vk_find_pipeline(const Vk_Pipeline_Desc& desc) {
    for (int i = 0; i < tr.vk_resources.num_pipelines; i++) {
        if (tr.vk_resources.pipeline_desc[i] == desc) {
            return tr.vk_resources.pipelines[i];
        }
    }

    if (tr.vk_resources.num_pipelines == MAX_VK_PIPELINES) {
        ri.Error( ERR_DROP, "vk_find_pipeline: MAX_VK_PIPELINES hit\n");
    }

    Timer t;
    VkPipeline pipeline = create_pipeline(desc);
    pipeline_create_time += t.Elapsed_Seconds();

    tr.vk_resources.pipeline_desc[tr.vk_resources.num_pipelines] = desc;
    tr.vk_resources.pipelines[tr.vk_resources.num_pipelines] = pipeline;
    tr.vk_resources.num_pipelines++;
    return pipeline;
}

static void vk_destroy_pipelines() {
    for (int i = 0; i < tr.vk_resources.num_pipelines; i++) {
        vkDestroyPipeline(vk.device, tr.vk_resources.pipelines[i], nullptr);
    }

    tr.vk_resources.num_pipelines = 0;
    Com_Memset(tr.vk_resources.pipelines, 0, sizeof(tr.vk_resources.pipelines));
    Com_Memset(tr.vk_resources.pipeline_desc, 0, sizeof(tr.vk_resources.pipeline_desc));

    pipeline_create_time = 0.0f;
}

VkDescriptorSet vk_create_descriptor_set(VkImageView image_view) {
    VkDescriptorSetAllocateInfo desc;
    desc.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
    desc.pNext = nullptr;
    desc.descriptorPool = vk.descriptor_pool;
    desc.descriptorSetCount = 1;
    desc.pSetLayouts = &vk.set_layout;

    VkDescriptorSet set;
    VkResult result = vkAllocateDescriptorSets(vk.device, &desc, &set);
    check_vk_result(result, "vkAllocateDescriptorSets");

    VkDescriptorImageInfo image_info;
    image_info.sampler = vulkan_demo->texture_image_sampler;
    image_info.imageView = image_view;
    image_info.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;

    std::array<VkWriteDescriptorSet, 1> descriptor_writes;
    descriptor_writes[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    descriptor_writes[0].dstSet = set;
    descriptor_writes[0].dstBinding = 0;
    descriptor_writes[0].dstArrayElement = 0;
    descriptor_writes[0].descriptorCount = 1;
    descriptor_writes[0].pNext = nullptr;
    descriptor_writes[0].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
    descriptor_writes[0].pImageInfo = &image_info;
    descriptor_writes[0].pBufferInfo = nullptr;
    descriptor_writes[0].pTexelBufferView = nullptr;

    vkUpdateDescriptorSets(vk.device, (uint32_t)descriptor_writes.size(), descriptor_writes.data(), 0, nullptr);
    return set;
}

void vk_destroy_resources() {
    vkDeviceWaitIdle(vk.device);
    vk_destroy_pipelines();

    vk.xyz_elements = 0;
    vk.color_st_elements = 0;
    vk.index_buffer_offset = 0;
}

VkRect2D vk_get_viewport_rect() {
    VkRect2D r;

    if (backEnd.projection2D) {
        r.offset.x = 0.0f;
        r.offset.y = 0.0f;
        r.extent.width = glConfig.vidWidth;
        r.extent.height = glConfig.vidHeight;
    } else {
        r.offset.x = backEnd.viewParms.viewportX;
        if (r.offset.x < 0)
            r.offset.x = 0;

        r.offset.y = glConfig.vidHeight - (backEnd.viewParms.viewportY + backEnd.viewParms.viewportHeight);
        if (r.offset.y < 0)
            r.offset.y = 0;

        r.extent.width = backEnd.viewParms.viewportWidth;
        if (r.offset.x + r.extent.width > glConfig.vidWidth)
            r.extent.width = glConfig.vidWidth - r.offset.x;

        r.extent.height = backEnd.viewParms.viewportHeight;
        if (r.offset.y + r.extent.height > glConfig.vidHeight)
            r.extent.height = glConfig.vidHeight - r.offset.y;
    }
    return r;
}

void vk_get_mvp_transform(float mvp[16]) {
    if (backEnd.projection2D) {
        float mvp0 = 2.0f / glConfig.vidWidth;
        float mvp5 = 2.0f / glConfig.vidHeight;

        mvp[0]  =  mvp0; mvp[1]  =  0.0f; mvp[2]  = 0.0f; mvp[3]  = 0.0f;
        mvp[4]  =  0.0f; mvp[5]  =  mvp5; mvp[6]  = 0.0f; mvp[7]  = 0.0f;
        mvp[8]  =  0.0f; mvp[9]  =  0.0f; mvp[10] = 1.0f; mvp[11] = 0.0f;
        mvp[12] = -1.0f; mvp[13] = -1.0f; mvp[14] = 0.0f; mvp[15] = 1.0f;

    } else {
        const float* p = backEnd.viewParms.projectionMatrix;

        // update q3's proj matrix (opengl) to vulkan conventions: z - [0, 1] instead of [-1, 1] and invert y direction
        float zNear	= r_znear->value;
        float zFar = tr.viewParms.zFar;
        float p10 = -zFar / (zFar - zNear);
        float p14 = -zFar*zNear / (zFar - zNear);
        float p5 = -p[5];

        float proj[16] = {
            p[0], p[1], p[2], p[3],
            p[4], p5, p[6], p[7],
            p[8], p[9], p10, p[11],
            p[12], p[13], p14, p[15]
        };

        extern void myGlMultMatrix( const float *a, const float *b, float *out );
        myGlMultMatrix(backEnd.or.modelMatrix, proj, mvp);
    }
}

void vk_bind_resources_shared_between_stages(int num_passes) {
    extern FILE* vk_log_file;
    if (r_logFile->integer)
        fprintf(vk_log_file, "render_tess (passes %d, vert %d, inds %d)\n", num_passes, tess.numVertexes, tess.numIndexes);

    // xyz
    {
        if ((vk.xyz_elements + tess.numVertexes) * sizeof(vec4_t) > XYZ_SIZE)
            ri.Error(ERR_DROP, "vulkan: vertex buffer overflow (xyz)\n");

        byte* dst = vk.vertex_buffer_ptr + XYZ_OFFSET + vk.xyz_elements * sizeof(vec4_t);
        Com_Memcpy(dst, tess.xyz, tess.numVertexes * sizeof(vec4_t));
    }

    std::size_t indexes_size = tess.numIndexes * sizeof(uint32_t);        

    // update index buffer
    {
        if (vk.index_buffer_offset + indexes_size > INDEX_BUFFER_SIZE)
            ri.Error(ERR_DROP, "vk_draw: index buffer overflow\n");

        byte* dst = vk.index_buffer_ptr + vk.index_buffer_offset;
        Com_Memcpy(dst, tess.indexes, indexes_size);
    }

    // configure indexes stream
    vkCmdBindIndexBuffer(vk.command_buffer, vk.index_buffer, vk.index_buffer_offset, VK_INDEX_TYPE_UINT32);
    vk.index_buffer_offset += indexes_size;

    // update mvp transform
    float mvp[16];
    vk_get_mvp_transform(mvp);
    vkCmdPushConstants(vk.command_buffer, vk.pipeline_layout, VK_SHADER_STAGE_VERTEX_BIT, 0, 64, mvp);
}

void vk_bind_stage_specific_resources(VkPipeline pipeline, bool multitexture, bool sky) {
    //
    // Specify color/st for each draw call since they are regenerated for each Q3 shader's stage.
    // xyz are specified only once for all stages.
    //

    // color
    {
        if ((vk.color_st_elements + tess.numVertexes) * sizeof(color4ub_t) > COLOR_SIZE)
            ri.Error(ERR_DROP, "vulkan: vertex buffer overflow (color)\n");

        byte* dst = vk.vertex_buffer_ptr + COLOR_OFFSET + vk.color_st_elements * sizeof(color4ub_t);
        Com_Memcpy(dst, tess.svars.colors, tess.numVertexes * sizeof(color4ub_t));
    }

    // st0
    {
        if ((vk.color_st_elements + tess.numVertexes) * sizeof(vec2_t) > ST0_SIZE)
            ri.Error(ERR_DROP, "vulkan: vertex buffer overflow (st0)\n");

        byte* dst = vk.vertex_buffer_ptr + ST0_OFFSET + vk.color_st_elements * sizeof(vec2_t);
        Com_Memcpy(dst, tess.svars.texcoords[0], tess.numVertexes * sizeof(vec2_t));
    }

    // st1
    if (multitexture) {
        if ((vk.color_st_elements + tess.numVertexes) * sizeof(vec2_t) > ST1_SIZE)
            ri.Error(ERR_DROP, "vulkan: vertex buffer overflow (st1)\n");

        byte* dst = vk.vertex_buffer_ptr + ST1_OFFSET + vk.color_st_elements * sizeof(vec2_t);
        Com_Memcpy(dst, tess.svars.texcoords[1], tess.numVertexes * sizeof(vec2_t));
    }

    // configure vertex data stream
    VkBuffer bufs[4] = { vk.vertex_buffer, vk.vertex_buffer, vk.vertex_buffer, vk.vertex_buffer }; // turtles all the way down
    VkDeviceSize offs[4] = {
        XYZ_OFFSET   + vk.xyz_elements * sizeof(vec4_t),
        COLOR_OFFSET + vk.color_st_elements * sizeof(color4ub_t),
        ST0_OFFSET   + vk.color_st_elements * sizeof(vec2_t),
        ST1_OFFSET   + vk.color_st_elements * sizeof(vec2_t)
    };

    vkCmdBindVertexBuffers(vk.command_buffer, 0, multitexture ? 4 : 3, bufs, offs);
    vk.color_st_elements += tess.numVertexes;

    // bind descriptor sets
    image_t* image = glState.vk_current_images[0];
    image_t* image2 = glState.vk_current_images[1];
    VkDescriptorSet sets[2] = { image->vk_descriptor_set, image2 ? image2->vk_descriptor_set : VkDescriptorSet() };
    vkCmdBindDescriptorSets(vk.command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, vk.pipeline_layout, 0, multitexture ? 2 : 1, sets, 0, nullptr);

    // bind pipeline
    vkCmdBindPipeline(vk.command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);

    // configure pipeline's dynamic state
    VkRect2D r = vk_get_viewport_rect();
    vkCmdSetScissor(vk.command_buffer, 0, 1, &r);

    VkViewport viewport;
    viewport.x = (float)r.offset.x;
    viewport.y = (float)r.offset.y;
    viewport.width = (float)r.extent.width;
    viewport.height = (float)r.extent.height;
    viewport.minDepth = 0.0f;
    viewport.maxDepth = 1.0f;

	if (backEnd.currentEntity->e.renderfx & RF_DEPTHHACK) {
		viewport.maxDepth = 0.3f;
	}

	if (sky) {
		if (r_showsky->integer) {
			viewport.minDepth = 0.0f;
			viewport.maxDepth = 0.0f;
		} else {
			viewport.minDepth = 1.0f;
			viewport.maxDepth = 1.0f;
		}
	}

    vkCmdSetViewport(vk.command_buffer, 0, 1, &viewport);

    if (tess.shader->polygonOffset) {
        vkCmdSetDepthBias(vk.command_buffer, r_offsetUnits->value, 0.0f, r_offsetFactor->value);
    }
}

void vk_begin_frame() {
	extern FILE* vk_log_file;
	if (r_logFile->integer)
		fprintf(vk_log_file, "vk_begin_frame\n");

	VkResult result = vkAcquireNextImageKHR(vk.device, vk.swapchain, UINT64_MAX, vulkan_demo->image_acquired, VK_NULL_HANDLE, &vulkan_demo->swapchain_image_index);
	check_vk_result(result, "vkAcquireNextImageKHR");

	result = vkWaitForFences(vk.device, 1, &vulkan_demo->rendering_finished_fence, VK_FALSE, 1e9);
	check_vk_result(result, "vkWaitForFences");
	result = vkResetFences(vk.device, 1, &vulkan_demo->rendering_finished_fence);
	check_vk_result(result, "vkResetFences");

	VkCommandBufferBeginInfo begin_info;
	begin_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
	begin_info.pNext = nullptr;
	begin_info.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
	begin_info.pInheritanceInfo = nullptr;

	result = vkBeginCommandBuffer(vk.command_buffer, &begin_info);
	check_vk_result(result, "vkBeginCommandBuffer");

	VkClearValue clear_values[2];
	/// ignore clear_values[0] which corresponds to color attachment
	clear_values[1].depthStencil.depth = 1.0;
	clear_values[1].depthStencil.stencil = 0;

	VkRenderPassBeginInfo render_pass_begin_info;
	render_pass_begin_info.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
	render_pass_begin_info.pNext = nullptr;
	render_pass_begin_info.renderPass = vk.render_pass;
	render_pass_begin_info.framebuffer = vk.framebuffers[vulkan_demo->swapchain_image_index];
	render_pass_begin_info.renderArea.offset = { 0, 0 };
	render_pass_begin_info.renderArea.extent = { (uint32_t)glConfig.vidWidth, (uint32_t)glConfig.vidHeight };
	render_pass_begin_info.clearValueCount = 2;
	render_pass_begin_info.pClearValues = clear_values;

	vkCmdBeginRenderPass(vk.command_buffer, &render_pass_begin_info, VK_SUBPASS_CONTENTS_INLINE);

	vk.xyz_elements = 0;
	vk.color_st_elements = 0;
	vk.index_buffer_offset = 0;

	glState.vk_dirty_attachments = false;
}