21_descriptor_layout.rs

use vulkan_tutorial_rust::{
    utility, // the mod define some fixed functions that have been learned before.
    utility::constants::*,
    utility::debug::*,
    utility::share,
    utility::structures::*,
    utility::window::{ProgramProc, VulkanApp},
};

use ash::version::DeviceV1_0;
use ash::version::InstanceV1_0;
use ash::vk;
use cgmath::{Deg, Matrix4, Point3, Vector3};

use std::ffi::CString;
use std::ptr;

// Constants
const WINDOW_TITLE: &'static str = "21.Descriptor Layout";

#[repr(C)]
#[derive(Clone, Debug, Copy)]
struct UniformBufferObject {
    model: Matrix4<f32>,
    view: Matrix4<f32>,
    proj: Matrix4<f32>,
}

struct VulkanApp21 {
    window: winit::window::Window,

    // vulkan stuff
    _entry: ash::Entry,
    instance: ash::Instance,
    surface_loader: ash::extensions::khr::Surface,
    surface: vk::SurfaceKHR,
    debug_utils_loader: ash::extensions::ext::DebugUtils,
    debug_merssager: vk::DebugUtilsMessengerEXT,

    physical_device: vk::PhysicalDevice,
    device: ash::Device,

    queue_family: QueueFamilyIndices,
    graphics_queue: vk::Queue,
    present_queue: vk::Queue,

    swapchain_loader: ash::extensions::khr::Swapchain,
    swapchain: vk::SwapchainKHR,
    swapchain_images: Vec<vk::Image>,
    swapchain_format: vk::Format,
    swapchain_extent: vk::Extent2D,
    swapchain_imageviews: Vec<vk::ImageView>,
    swapchain_framebuffers: Vec<vk::Framebuffer>,

    render_pass: vk::RenderPass,
    ubo_layout: vk::DescriptorSetLayout,
    pipeline_layout: vk::PipelineLayout,
    graphics_pipeline: vk::Pipeline,

    vertex_buffer: vk::Buffer,
    vertex_buffer_memory: vk::DeviceMemory,
    index_buffer: vk::Buffer,
    index_buffer_memory: vk::DeviceMemory,

    uniform_buffers: Vec<vk::Buffer>,
    uniform_buffers_memory: Vec<vk::DeviceMemory>,

    command_pool: vk::CommandPool,
    command_buffers: Vec<vk::CommandBuffer>,

    image_available_semaphores: Vec<vk::Semaphore>,
    render_finished_semaphores: Vec<vk::Semaphore>,
    in_flight_fences: Vec<vk::Fence>,
    current_frame: usize,

    is_framebuffer_resized: bool,
}

impl VulkanApp21 {
    pub fn new(event_loop: &winit::event_loop::EventLoop<()>) -> VulkanApp21 {
        let window =
            utility::window::init_window(event_loop, WINDOW_TITLE, WINDOW_WIDTH, WINDOW_HEIGHT);

        // init vulkan stuff
        let entry = ash::Entry::new().unwrap();
        let instance = share::create_instance(
            &entry,
            WINDOW_TITLE,
            VALIDATION.is_enable,
            &VALIDATION.required_validation_layers.to_vec(),
        );
        let surface_stuff =
            share::create_surface(&entry, &instance, &window, WINDOW_WIDTH, WINDOW_HEIGHT);
        let (debug_utils_loader, debug_merssager) =
            setup_debug_utils(VALIDATION.is_enable, &entry, &instance);
        let physical_device =
            share::pick_physical_device(&instance, &surface_stuff, &DEVICE_EXTENSIONS);
        let physical_device_memory_properties =
            unsafe { instance.get_physical_device_memory_properties(physical_device) };
        let (device, queue_family) = share::create_logical_device(
            &instance,
            physical_device,
            &VALIDATION,
            &DEVICE_EXTENSIONS,
            &surface_stuff,
        );
        let graphics_queue =
            unsafe { device.get_device_queue(queue_family.graphics_family.unwrap(), 0) };
        let present_queue =
            unsafe { device.get_device_queue(queue_family.present_family.unwrap(), 0) };
        let swapchain_stuff = share::create_swapchain(
            &instance,
            &device,
            physical_device,
            &window,
            &surface_stuff,
            &queue_family,
        );
        let swapchain_imageviews = share::v1::create_image_views(
            &device,
            swapchain_stuff.swapchain_format,
            &swapchain_stuff.swapchain_images,
        );
        let render_pass = share::v1::create_render_pass(&device, swapchain_stuff.swapchain_format);
        let ubo_layout = VulkanApp21::create_descriptor_set_layout(&device);
        let (graphics_pipeline, pipeline_layout) = VulkanApp21::create_graphics_pipeline(
            &device,
            render_pass,
            swapchain_stuff.swapchain_extent,
            ubo_layout,
        );
        let swapchain_framebuffers = share::v1::create_framebuffers(
            &device,
            render_pass,
            &swapchain_imageviews,
            swapchain_stuff.swapchain_extent,
        );
        let command_pool = share::v1::create_command_pool(&device, &queue_family);
        let (vertex_buffer, vertex_buffer_memory) = share::v1::create_vertex_buffer(
            &device,
            &physical_device_memory_properties,
            command_pool,
            graphics_queue,
            &RECT_VERTICES_DATA,
        );
        let (index_buffer, index_buffer_memory) = share::v1::create_index_buffer(
            &device,
            &physical_device_memory_properties,
            command_pool,
            graphics_queue,
            &RECT_INDICES_DATA,
        );
        let (uniform_buffers, uniform_buffers_memory) = VulkanApp21::create_uniform_buffers(
            &device,
            &physical_device_memory_properties,
            swapchain_stuff.swapchain_images.len(),
        );
        let command_buffers = VulkanApp21::create_command_buffers(
            &device,
            command_pool,
            graphics_pipeline,
            &swapchain_framebuffers,
            render_pass,
            swapchain_stuff.swapchain_extent,
            vertex_buffer,
            index_buffer,
        );
        let sync_ojbects = share::v1::create_sync_objects(&device, MAX_FRAMES_IN_FLIGHT);

        // cleanup(); the 'drop' function will take care of it.
        VulkanApp21 {
            // winit stuff
            window,

            // vulkan stuff
            _entry: entry,
            instance,
            surface: surface_stuff.surface,
            surface_loader: surface_stuff.surface_loader,
            debug_utils_loader,
            debug_merssager,

            physical_device,
            device,

            queue_family,
            graphics_queue,
            present_queue,

            swapchain_loader: swapchain_stuff.swapchain_loader,
            swapchain: swapchain_stuff.swapchain,
            swapchain_format: swapchain_stuff.swapchain_format,
            swapchain_images: swapchain_stuff.swapchain_images,
            swapchain_extent: swapchain_stuff.swapchain_extent,
            swapchain_imageviews,
            swapchain_framebuffers,

            pipeline_layout,
            ubo_layout,
            render_pass,
            graphics_pipeline,

            vertex_buffer,
            vertex_buffer_memory,
            index_buffer,
            index_buffer_memory,

            uniform_buffers,
            uniform_buffers_memory,

            command_pool,
            command_buffers,

            image_available_semaphores: sync_ojbects.image_available_semaphores,
            render_finished_semaphores: sync_ojbects.render_finished_semaphores,
            in_flight_fences: sync_ojbects.inflight_fences,
            current_frame: 0,

            is_framebuffer_resized: false,
        }
    }

    fn create_descriptor_set_layout(device: &ash::Device) -> vk::DescriptorSetLayout {
        let ubo_layout_bindings = [vk::DescriptorSetLayoutBinding {
            binding: 0,
            descriptor_type: vk::DescriptorType::UNIFORM_BUFFER,
            descriptor_count: 1,
            stage_flags: vk::ShaderStageFlags::VERTEX,
            p_immutable_samplers: ptr::null(),
        }];

        let ubo_layout_create_info = vk::DescriptorSetLayoutCreateInfo {
            s_type: vk::StructureType::DESCRIPTOR_SET_LAYOUT_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::DescriptorSetLayoutCreateFlags::empty(),
            binding_count: ubo_layout_bindings.len() as u32,
            p_bindings: ubo_layout_bindings.as_ptr(),
        };

        unsafe {
            device
                .create_descriptor_set_layout(&ubo_layout_create_info, None)
                .expect("Failed to create Descriptor Set Layout!")
        }
    }

    fn create_uniform_buffers(
        device: &ash::Device,
        device_memory_properties: &vk::PhysicalDeviceMemoryProperties,
        swapchain_image_count: usize,
    ) -> (Vec<vk::Buffer>, Vec<vk::DeviceMemory>) {
        let buffer_size = std::mem::size_of::<UniformBufferObject>();

        let mut uniform_buffers = vec![];
        let mut uniform_buffers_memory = vec![];

        for _ in 0..swapchain_image_count {
            let (uniform_buffer, uniform_buffer_memory) = share::create_buffer(
                device,
                buffer_size as u64,
                vk::BufferUsageFlags::UNIFORM_BUFFER,
                vk::MemoryPropertyFlags::HOST_VISIBLE | vk::MemoryPropertyFlags::HOST_COHERENT,
                device_memory_properties,
            );
            uniform_buffers.push(uniform_buffer);
            uniform_buffers_memory.push(uniform_buffer_memory);
        }

        (uniform_buffers, uniform_buffers_memory)
    }

    fn update_uniform_buffer(&self, current_image: usize, delta_time: f32) {
        let ubos = [UniformBufferObject {
            model: Matrix4::from_angle_z(Deg(90.0 * delta_time)),
            view: Matrix4::look_at(
                Point3::new(2.0, 2.0, 2.0),
                Point3::new(0.0, 0.0, 0.0),
                Vector3::new(0.0, 0.0, 1.0),
            ),
            proj: cgmath::perspective(
                Deg(45.0),
                self.swapchain_extent.width as f32 / self.swapchain_extent.height as f32,
                0.1,
                10.0,
            ),
        }];

        let buffer_size = (std::mem::size_of::<UniformBufferObject>() * ubos.len()) as u64;

        unsafe {
            let data_ptr =
                self.device
                    .map_memory(
                        self.uniform_buffers_memory[current_image],
                        0,
                        buffer_size,
                        vk::MemoryMapFlags::empty(),
                    )
                    .expect("Failed to Map Memory") as *mut UniformBufferObject;

            data_ptr.copy_from_nonoverlapping(ubos.as_ptr(), ubos.len());

            self.device
                .unmap_memory(self.uniform_buffers_memory[current_image]);
        }
    }

    fn create_graphics_pipeline(
        device: &ash::Device,
        render_pass: vk::RenderPass,
        swapchain_extent: vk::Extent2D,
        ubo_set_layout: vk::DescriptorSetLayout,
    ) -> (vk::Pipeline, vk::PipelineLayout) {
        let vert_shader_module = share::create_shader_module(
            device,
            include_bytes!("../../shaders/spv/21-shader-ubo.vert.spv").to_vec(),
        );
        let frag_shader_module = share::create_shader_module(
            device,
            include_bytes!("../../shaders/spv/21-shader-ubo.frag.spv").to_vec(),
        );

        let main_function_name = CString::new("main").unwrap(); // the beginning function name in shader code.

        let shader_stages = [
            vk::PipelineShaderStageCreateInfo {
                // Vertex Shader
                s_type: vk::StructureType::PIPELINE_SHADER_STAGE_CREATE_INFO,
                p_next: ptr::null(),
                flags: vk::PipelineShaderStageCreateFlags::empty(),
                module: vert_shader_module,
                p_name: main_function_name.as_ptr(),
                p_specialization_info: ptr::null(),
                stage: vk::ShaderStageFlags::VERTEX,
            },
            vk::PipelineShaderStageCreateInfo {
                // Fragment Shader
                s_type: vk::StructureType::PIPELINE_SHADER_STAGE_CREATE_INFO,
                p_next: ptr::null(),
                flags: vk::PipelineShaderStageCreateFlags::empty(),
                module: frag_shader_module,
                p_name: main_function_name.as_ptr(),
                p_specialization_info: ptr::null(),
                stage: vk::ShaderStageFlags::FRAGMENT,
            },
        ];

        let binding_description = VertexV1::get_binding_description();
        let attribute_description = VertexV1::get_attribute_descriptions();

        let vertex_input_state_create_info = vk::PipelineVertexInputStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineVertexInputStateCreateFlags::empty(),
            vertex_attribute_description_count: attribute_description.len() as u32,
            p_vertex_attribute_descriptions: attribute_description.as_ptr(),
            vertex_binding_description_count: binding_description.len() as u32,
            p_vertex_binding_descriptions: binding_description.as_ptr(),
        };
        let vertex_input_assembly_state_info = vk::PipelineInputAssemblyStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO,
            flags: vk::PipelineInputAssemblyStateCreateFlags::empty(),
            p_next: ptr::null(),
            primitive_restart_enable: vk::FALSE,
            topology: vk::PrimitiveTopology::TRIANGLE_LIST,
        };

        let viewports = [vk::Viewport {
            x: 0.0,
            y: 0.0,
            width: swapchain_extent.width as f32,
            height: swapchain_extent.height as f32,
            min_depth: 0.0,
            max_depth: 1.0,
        }];

        let scissors = [vk::Rect2D {
            offset: vk::Offset2D { x: 0, y: 0 },
            extent: swapchain_extent,
        }];

        let viewport_state_create_info = vk::PipelineViewportStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_VIEWPORT_STATE_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineViewportStateCreateFlags::empty(),
            scissor_count: scissors.len() as u32,
            p_scissors: scissors.as_ptr(),
            viewport_count: viewports.len() as u32,
            p_viewports: viewports.as_ptr(),
        };

        let rasterization_statue_create_info = vk::PipelineRasterizationStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_RASTERIZATION_STATE_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineRasterizationStateCreateFlags::empty(),
            depth_clamp_enable: vk::FALSE,
            cull_mode: vk::CullModeFlags::BACK,
            front_face: vk::FrontFace::CLOCKWISE,
            line_width: 1.0,
            polygon_mode: vk::PolygonMode::FILL,
            rasterizer_discard_enable: vk::FALSE,
            depth_bias_clamp: 0.0,
            depth_bias_constant_factor: 0.0,
            depth_bias_enable: vk::FALSE,
            depth_bias_slope_factor: 0.0,
        };

        let multisample_state_create_info = vk::PipelineMultisampleStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_MULTISAMPLE_STATE_CREATE_INFO,
            flags: vk::PipelineMultisampleStateCreateFlags::empty(),
            p_next: ptr::null(),
            rasterization_samples: vk::SampleCountFlags::TYPE_1,
            sample_shading_enable: vk::FALSE,
            min_sample_shading: 0.0,
            p_sample_mask: ptr::null(),
            alpha_to_one_enable: vk::FALSE,
            alpha_to_coverage_enable: vk::FALSE,
        };

        let stencil_state = vk::StencilOpState {
            fail_op: vk::StencilOp::KEEP,
            pass_op: vk::StencilOp::KEEP,
            depth_fail_op: vk::StencilOp::KEEP,
            compare_op: vk::CompareOp::ALWAYS,
            compare_mask: 0,
            write_mask: 0,
            reference: 0,
        };

        let depth_state_create_info = vk::PipelineDepthStencilStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineDepthStencilStateCreateFlags::empty(),
            depth_test_enable: vk::FALSE,
            depth_write_enable: vk::FALSE,
            depth_compare_op: vk::CompareOp::LESS_OR_EQUAL,
            depth_bounds_test_enable: vk::FALSE,
            stencil_test_enable: vk::FALSE,
            front: stencil_state,
            back: stencil_state,
            max_depth_bounds: 1.0,
            min_depth_bounds: 0.0,
        };

        let color_blend_attachment_states = [vk::PipelineColorBlendAttachmentState {
            blend_enable: vk::FALSE,
            color_write_mask: vk::ColorComponentFlags::all(),
            src_color_blend_factor: vk::BlendFactor::ONE,
            dst_color_blend_factor: vk::BlendFactor::ZERO,
            color_blend_op: vk::BlendOp::ADD,
            src_alpha_blend_factor: vk::BlendFactor::ONE,
            dst_alpha_blend_factor: vk::BlendFactor::ZERO,
            alpha_blend_op: vk::BlendOp::ADD,
        }];

        let color_blend_state = vk::PipelineColorBlendStateCreateInfo {
            s_type: vk::StructureType::PIPELINE_COLOR_BLEND_STATE_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineColorBlendStateCreateFlags::empty(),
            logic_op_enable: vk::FALSE,
            logic_op: vk::LogicOp::COPY,
            attachment_count: color_blend_attachment_states.len() as u32,
            p_attachments: color_blend_attachment_states.as_ptr(),
            blend_constants: [0.0, 0.0, 0.0, 0.0],
        };

        let set_layouts = [ubo_set_layout];

        let pipeline_layout_create_info = vk::PipelineLayoutCreateInfo {
            s_type: vk::StructureType::PIPELINE_LAYOUT_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineLayoutCreateFlags::empty(),
            set_layout_count: set_layouts.len() as u32,
            p_set_layouts: set_layouts.as_ptr(),
            push_constant_range_count: 0,
            p_push_constant_ranges: ptr::null(),
        };

        let pipeline_layout = unsafe {
            device
                .create_pipeline_layout(&pipeline_layout_create_info, None)
                .expect("Failed to create pipeline layout!")
        };

        let graphic_pipeline_create_infos = [vk::GraphicsPipelineCreateInfo {
            s_type: vk::StructureType::GRAPHICS_PIPELINE_CREATE_INFO,
            p_next: ptr::null(),
            flags: vk::PipelineCreateFlags::empty(),
            stage_count: shader_stages.len() as u32,
            p_stages: shader_stages.as_ptr(),
            p_vertex_input_state: &vertex_input_state_create_info,
            p_input_assembly_state: &vertex_input_assembly_state_info,
            p_tessellation_state: ptr::null(),
            p_viewport_state: &viewport_state_create_info,
            p_rasterization_state: &rasterization_statue_create_info,
            p_multisample_state: &multisample_state_create_info,
            p_depth_stencil_state: &depth_state_create_info,
            p_color_blend_state: &color_blend_state,
            p_dynamic_state: ptr::null(),
            layout: pipeline_layout,
            render_pass,
            subpass: 0,
            base_pipeline_handle: vk::Pipeline::null(),
            base_pipeline_index: -1,
        }];

        let graphics_pipelines = unsafe {
            device
                .create_graphics_pipelines(
                    vk::PipelineCache::null(),
                    &graphic_pipeline_create_infos,
                    None,
                )
                .expect("Failed to create Graphics Pipeline!.")
        };

        unsafe {
            device.destroy_shader_module(vert_shader_module, None);
            device.destroy_shader_module(frag_shader_module, None);
        }

        (graphics_pipelines[0], pipeline_layout)
    }
}

// Fix content -------------------------------------------------------------------------------
impl VulkanApp21 {
    fn create_command_buffers(
        device: &ash::Device,
        command_pool: vk::CommandPool,
        graphics_pipeline: vk::Pipeline,
        framebuffers: &Vec<vk::Framebuffer>,
        render_pass: vk::RenderPass,
        surface_extent: vk::Extent2D,
        vertex_buffer: vk::Buffer,
        index_buffer: vk::Buffer,
    ) -> Vec<vk::CommandBuffer> {
        let command_buffer_allocate_info = vk::CommandBufferAllocateInfo {
            s_type: vk::StructureType::COMMAND_BUFFER_ALLOCATE_INFO,
            p_next: ptr::null(),
            command_buffer_count: framebuffers.len() as u32,
            command_pool,
            level: vk::CommandBufferLevel::PRIMARY,
        };

        let command_buffers = unsafe {
            device
                .allocate_command_buffers(&command_buffer_allocate_info)
                .expect("Failed to allocate Command Buffers!")
        };

        for (i, &command_buffer) in command_buffers.iter().enumerate() {
            let command_buffer_begin_info = vk::CommandBufferBeginInfo {
                s_type: vk::StructureType::COMMAND_BUFFER_BEGIN_INFO,
                p_next: ptr::null(),
                p_inheritance_info: ptr::null(),
                flags: vk::CommandBufferUsageFlags::SIMULTANEOUS_USE,
            };

            unsafe {
                device
                    .begin_command_buffer(command_buffer, &command_buffer_begin_info)
                    .expect("Failed to begin recording Command Buffer at beginning!");
            }

            let clear_values = [vk::ClearValue {
                color: vk::ClearColorValue {
                    float32: [0.0, 0.0, 0.0, 1.0],
                },
            }];

            let render_pass_begin_info = vk::RenderPassBeginInfo {
                s_type: vk::StructureType::RENDER_PASS_BEGIN_INFO,
                p_next: ptr::null(),
                render_pass,
                framebuffer: framebuffers[i],
                render_area: vk::Rect2D {
                    offset: vk::Offset2D { x: 0, y: 0 },
                    extent: surface_extent,
                },
                clear_value_count: clear_values.len() as u32,
                p_clear_values: clear_values.as_ptr(),
            };

            unsafe {
                device.cmd_begin_render_pass(
                    command_buffer,
                    &render_pass_begin_info,
                    vk::SubpassContents::INLINE,
                );
                device.cmd_bind_pipeline(
                    command_buffer,
                    vk::PipelineBindPoint::GRAPHICS,
                    graphics_pipeline,
                );

                let vertex_buffers = [vertex_buffer];
                let offsets = [0_u64];

                device.cmd_bind_vertex_buffers(command_buffer, 0, &vertex_buffers, &offsets);
                device.cmd_bind_index_buffer(
                    command_buffer,
                    index_buffer,
                    0,
                    vk::IndexType::UINT32,
                );

                device.cmd_draw_indexed(command_buffer, RECT_INDICES_DATA.len() as u32, 1, 0, 0, 0);

                device.cmd_end_render_pass(command_buffer);

                device
                    .end_command_buffer(command_buffer)
                    .expect("Failed to record Command Buffer at Ending!");
            }
        }

        command_buffers
    }
}

impl Drop for VulkanApp21 {
    fn drop(&mut self) {
        unsafe {
            for i in 0..MAX_FRAMES_IN_FLIGHT {
                self.device
                    .destroy_semaphore(self.image_available_semaphores[i], None);
                self.device
                    .destroy_semaphore(self.render_finished_semaphores[i], None);
                self.device.destroy_fence(self.in_flight_fences[i], None);
            }

            self.cleanup_swapchain();

            self.device
                .destroy_descriptor_set_layout(self.ubo_layout, None);

            for i in 0..self.uniform_buffers.len() {
                self.device.destroy_buffer(self.uniform_buffers[i], None);
                self.device
                    .free_memory(self.uniform_buffers_memory[i], None);
            }

            self.device.destroy_buffer(self.index_buffer, None);
            self.device.free_memory(self.index_buffer_memory, None);

            self.device.destroy_buffer(self.vertex_buffer, None);
            self.device.free_memory(self.vertex_buffer_memory, None);

            self.device.destroy_command_pool(self.command_pool, None);

            self.device.destroy_device(None);
            self.surface_loader.destroy_surface(self.surface, None);

            if VALIDATION.is_enable {
                self.debug_utils_loader
                    .destroy_debug_utils_messenger(self.debug_merssager, None);
            }
            self.instance.destroy_instance(None);
        }
    }
}

impl VulkanApp for VulkanApp21 {
    fn draw_frame(&mut self, delta_time: f32) {
        let wait_fences = [self.in_flight_fences[self.current_frame]];

        unsafe {
            self.device
                .wait_for_fences(&wait_fences, true, std::u64::MAX)
                .expect("Failed to wait for Fence!");
        }

        let (image_index, _is_sub_optimal) = unsafe {
            let result = self.swapchain_loader.acquire_next_image(
                self.swapchain,
                std::u64::MAX,
                self.image_available_semaphores[self.current_frame],
                vk::Fence::null(),
            );
            match result {
                Ok(image_index) => image_index,
                Err(vk_result) => match vk_result {
                    vk::Result::ERROR_OUT_OF_DATE_KHR => {
                        self.recreate_swapchain();
                        return;
                    }
                    _ => panic!("Failed to acquire Swap Chain Image!"),
                },
            }
        };

        self.update_uniform_buffer(image_index as usize, delta_time);

        let wait_semaphores = [self.image_available_semaphores[self.current_frame]];
        let wait_stages = [vk::PipelineStageFlags::COLOR_ATTACHMENT_OUTPUT];
        let signal_semaphores = [self.render_finished_semaphores[self.current_frame]];

        let submit_infos = [vk::SubmitInfo {
            s_type: vk::StructureType::SUBMIT_INFO,
            p_next: ptr::null(),
            wait_semaphore_count: wait_semaphores.len() as u32,
            p_wait_semaphores: wait_semaphores.as_ptr(),
            p_wait_dst_stage_mask: wait_stages.as_ptr(),
            command_buffer_count: 1,
            p_command_buffers: &self.command_buffers[image_index as usize],
            signal_semaphore_count: signal_semaphores.len() as u32,
            p_signal_semaphores: signal_semaphores.as_ptr(),
        }];

        unsafe {
            self.device
                .reset_fences(&wait_fences)
                .expect("Failed to reset Fence!");

            self.device
                .queue_submit(
                    self.graphics_queue,
                    &submit_infos,
                    self.in_flight_fences[self.current_frame],
                )
                .expect("Failed to execute queue submit.");
        }

        let swapchains = [self.swapchain];

        let present_info = vk::PresentInfoKHR {
            s_type: vk::StructureType::PRESENT_INFO_KHR,
            p_next: ptr::null(),
            wait_semaphore_count: 1,
            p_wait_semaphores: signal_semaphores.as_ptr(),
            swapchain_count: 1,
            p_swapchains: swapchains.as_ptr(),
            p_image_indices: &image_index,
            p_results: ptr::null_mut(),
        };

        let result = unsafe {
            self.swapchain_loader
                .queue_present(self.present_queue, &present_info)
        };

        let is_resized = match result {
            Ok(_) => self.is_framebuffer_resized,
            Err(vk_result) => match vk_result {
                vk::Result::ERROR_OUT_OF_DATE_KHR | vk::Result::SUBOPTIMAL_KHR => true,
                _ => panic!("Failed to execute queue present."),
            },
        };
        if is_resized {
            self.is_framebuffer_resized = false;
            self.recreate_swapchain();
        }

        self.current_frame = (self.current_frame + 1) % MAX_FRAMES_IN_FLIGHT;
    }

    fn recreate_swapchain(&mut self) {
        // parameters -------------
        let surface_suff = SurfaceStuff {
            surface_loader: self.surface_loader.clone(),
            surface: self.surface,
            screen_width: WINDOW_WIDTH,
            screen_height: WINDOW_HEIGHT,
        };
        // ------------------------

        unsafe {
            self.device
                .device_wait_idle()
                .expect("Failed to wait device idle!")
        };
        self.cleanup_swapchain();

        let swapchain_stuff = share::create_swapchain(
            &self.instance,
            &self.device,
            self.physical_device,
            &self.window,
            &surface_suff,
            &self.queue_family,
        );
        self.swapchain_loader = swapchain_stuff.swapchain_loader;
        self.swapchain = swapchain_stuff.swapchain;
        self.swapchain_images = swapchain_stuff.swapchain_images;
        self.swapchain_format = swapchain_stuff.swapchain_format;
        self.swapchain_extent = swapchain_stuff.swapchain_extent;

        self.swapchain_imageviews = share::v1::create_image_views(
            &self.device,
            self.swapchain_format,
            &self.swapchain_images,
        );
        self.render_pass = share::v1::create_render_pass(&self.device, self.swapchain_format);
        let (graphics_pipeline, pipeline_layout) = VulkanApp21::create_graphics_pipeline(
            &self.device,
            self.render_pass,
            swapchain_stuff.swapchain_extent,
            self.ubo_layout,
        );
        self.graphics_pipeline = graphics_pipeline;
        self.pipeline_layout = pipeline_layout;

        self.swapchain_framebuffers = share::v1::create_framebuffers(
            &self.device,
            self.render_pass,
            &self.swapchain_imageviews,
            self.swapchain_extent,
        );
        self.command_buffers = VulkanApp21::create_command_buffers(
            &self.device,
            self.command_pool,
            self.graphics_pipeline,
            &self.swapchain_framebuffers,
            self.render_pass,
            self.swapchain_extent,
            self.vertex_buffer,
            self.index_buffer,
        );
    }

    fn cleanup_swapchain(&self) {
        unsafe {
            self.device
                .free_command_buffers(self.command_pool, &self.command_buffers);
            for &framebuffer in self.swapchain_framebuffers.iter() {
                self.device.destroy_framebuffer(framebuffer, None);
            }
            self.device.destroy_pipeline(self.graphics_pipeline, None);
            self.device
                .destroy_pipeline_layout(self.pipeline_layout, None);
            self.device.destroy_render_pass(self.render_pass, None);
            for &image_view in self.swapchain_imageviews.iter() {
                self.device.destroy_image_view(image_view, None);
            }
            self.swapchain_loader
                .destroy_swapchain(self.swapchain, None);
        }
    }

    fn wait_device_idle(&self) {
        unsafe {
            self.device
                .device_wait_idle()
                .expect("Failed to wait device idle!")
        };
    }

    fn resize_framebuffer(&mut self) {
        self.is_framebuffer_resized = true;
    }

    fn window_ref(&self) -> &winit::window::Window {
        &self.window
    }
}

fn main() {
    let program_proc = ProgramProc::new();
    let vulkan_app = VulkanApp21::new(&program_proc.event_loop);

    program_proc.main_loop(vulkan_app);
}
// -------------------------------------------------------------------------------------------