// ImGui Renderer for: Vulkan
// This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)

// Missing features:
//  [ ] User texture binding. Changes of ImTextureID aren't supported by this binding! See https://github.com/ocornut/imgui/pull/914

// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
// If you use this binding you'll need to call 5 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXX_CreateFontsTexture(), ImGui_ImplXXXX_NewFrame(), ImGui_ImplXXXX_Render() and ImGui_ImplXXXX_Shutdown().
// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
// https://github.com/ocornut/imgui

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
//  2018-03-01: Vulkan: Renamed ImGui_ImplVulkan_Init_Info to ImGui_ImplVulkan_InitInfo and fields to match more closely Vulkan terminology.
//  2018-02-18: Vulkan: Offset projection matrix and clipping rectangle by io.DisplayPos (which will be non-zero for multi-viewport applications).
//  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback, ImGui_ImplVulkan_Render() calls ImGui_ImplVulkan_RenderDrawData() itself.
//  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
//  2017-05-15: Vulkan: Fix scissor offset being negative. Fix new Vulkan validation warnings. Set required depth member for buffer image copy.
//  2016-11-13: Vulkan: Fix validation layer warnings and errors and redeclare gl_PerVertex.
//  2016-10-18: Vulkan: Add location decorators & change to use structs as in/out in glsl, update embedded spv (produced with glslangValidator -x). Null the released resources.
//  2016-08-27: Vulkan: Fix Vulkan example for use when a depth buffer is active.

#include "imgui.h"
#include "imgui_impl_vulkan.h"

// Vulkan data
static const VkAllocationCallbacks* g_Allocator = NULL;
static VkPhysicalDevice             g_PhysicalDevice = VK_NULL_HANDLE;
static VkDevice                     g_Device = VK_NULL_HANDLE;
static VkRenderPass                 g_RenderPass = VK_NULL_HANDLE;
static VkPipelineCache              g_PipelineCache = VK_NULL_HANDLE;
static VkDescriptorPool             g_DescriptorPool = VK_NULL_HANDLE;
static void                         (*g_CheckVkResult)(VkResult err) = NULL;

static VkCommandBuffer        g_CommandBuffer = VK_NULL_HANDLE;
static VkDeviceSize           g_BufferMemoryAlignment = 256;
static VkPipelineCreateFlags  g_PipelineCreateFlags = 0;
static int                    g_FrameIndex = 0;

static VkDescriptorSetLayout  g_DescriptorSetLayout = VK_NULL_HANDLE;
static VkPipelineLayout       g_PipelineLayout = VK_NULL_HANDLE;
static VkDescriptorSet        g_DescriptorSet = VK_NULL_HANDLE;
static VkPipeline             g_Pipeline = VK_NULL_HANDLE;

static VkSampler              g_FontSampler = VK_NULL_HANDLE;
static VkDeviceMemory         g_FontMemory = VK_NULL_HANDLE;
static VkImage                g_FontImage = VK_NULL_HANDLE;
static VkImageView            g_FontView = VK_NULL_HANDLE;

static VkDeviceMemory         g_VertexBufferMemory[IMGUI_VK_QUEUED_FRAMES] = {};
static VkDeviceMemory         g_IndexBufferMemory[IMGUI_VK_QUEUED_FRAMES] = {};
static VkDeviceSize           g_VertexBufferSize[IMGUI_VK_QUEUED_FRAMES] = {};
static VkDeviceSize           g_IndexBufferSize[IMGUI_VK_QUEUED_FRAMES] = {};
static VkBuffer               g_VertexBuffer[IMGUI_VK_QUEUED_FRAMES] = {};
static VkBuffer               g_IndexBuffer[IMGUI_VK_QUEUED_FRAMES] = {};

static VkDeviceMemory         g_UploadBufferMemory = VK_NULL_HANDLE;
static VkBuffer               g_UploadBuffer = VK_NULL_HANDLE;

// Forward Declarations
static void ImGui_ImplVulkan_InitPlatformInterface();
static void ImGui_ImplVulkan_ShutdownPlatformInterface();

static uint32_t __glsl_shader_vert_spv[] =
{
    0x07230203,0x00010000,0x00080001,0x0000002e,0x00000000,0x00020011,0x00000001,0x0006000b,
    0x00000001,0x4c534c47,0x6474732e,0x3035342e,0x00000000,0x0003000e,0x00000000,0x00000001,
    0x000a000f,0x00000000,0x00000004,0x6e69616d,0x00000000,0x0000000b,0x0000000f,0x00000015,
    0x0000001b,0x0000001c,0x00030003,0x00000002,0x000001c2,0x00040005,0x00000004,0x6e69616d,
    0x00000000,0x00030005,0x00000009,0x00000000,0x00050006,0x00000009,0x00000000,0x6f6c6f43,
    0x00000072,0x00040006,0x00000009,0x00000001,0x00005655,0x00030005,0x0000000b,0x0074754f,
    0x00040005,0x0000000f,0x6c6f4361,0x0000726f,0x00030005,0x00000015,0x00565561,0x00060005,
    0x00000019,0x505f6c67,0x65567265,0x78657472,0x00000000,0x00060006,0x00000019,0x00000000,
    0x505f6c67,0x7469736f,0x006e6f69,0x00030005,0x0000001b,0x00000000,0x00040005,0x0000001c,
    0x736f5061,0x00000000,0x00060005,0x0000001e,0x73755075,0x6e6f4368,0x6e617473,0x00000074,
    0x00050006,0x0000001e,0x00000000,0x61635375,0x0000656c,0x00060006,0x0000001e,0x00000001,
    0x61725475,0x616c736e,0x00006574,0x00030005,0x00000020,0x00006370,0x00040047,0x0000000b,
    0x0000001e,0x00000000,0x00040047,0x0000000f,0x0000001e,0x00000002,0x00040047,0x00000015,
    0x0000001e,0x00000001,0x00050048,0x00000019,0x00000000,0x0000000b,0x00000000,0x00030047,
    0x00000019,0x00000002,0x00040047,0x0000001c,0x0000001e,0x00000000,0x00050048,0x0000001e,
    0x00000000,0x00000023,0x00000000,0x00050048,0x0000001e,0x00000001,0x00000023,0x00000008,
    0x00030047,0x0000001e,0x00000002,0x00020013,0x00000002,0x00030021,0x00000003,0x00000002,
    0x00030016,0x00000006,0x00000020,0x00040017,0x00000007,0x00000006,0x00000004,0x00040017,
    0x00000008,0x00000006,0x00000002,0x0004001e,0x00000009,0x00000007,0x00000008,0x00040020,
    0x0000000a,0x00000003,0x00000009,0x0004003b,0x0000000a,0x0000000b,0x00000003,0x00040015,
    0x0000000c,0x00000020,0x00000001,0x0004002b,0x0000000c,0x0000000d,0x00000000,0x00040020,
    0x0000000e,0x00000001,0x00000007,0x0004003b,0x0000000e,0x0000000f,0x00000001,0x00040020,
    0x00000011,0x00000003,0x00000007,0x0004002b,0x0000000c,0x00000013,0x00000001,0x00040020,
    0x00000014,0x00000001,0x00000008,0x0004003b,0x00000014,0x00000015,0x00000001,0x00040020,
    0x00000017,0x00000003,0x00000008,0x0003001e,0x00000019,0x00000007,0x00040020,0x0000001a,
    0x00000003,0x00000019,0x0004003b,0x0000001a,0x0000001b,0x00000003,0x0004003b,0x00000014,
    0x0000001c,0x00000001,0x0004001e,0x0000001e,0x00000008,0x00000008,0x00040020,0x0000001f,
    0x00000009,0x0000001e,0x0004003b,0x0000001f,0x00000020,0x00000009,0x00040020,0x00000021,
    0x00000009,0x00000008,0x0004002b,0x00000006,0x00000028,0x00000000,0x0004002b,0x00000006,
    0x00000029,0x3f800000,0x00050036,0x00000002,0x00000004,0x00000000,0x00000003,0x000200f8,
    0x00000005,0x0004003d,0x00000007,0x00000010,0x0000000f,0x00050041,0x00000011,0x00000012,
    0x0000000b,0x0000000d,0x0003003e,0x00000012,0x00000010,0x0004003d,0x00000008,0x00000016,
    0x00000015,0x00050041,0x00000017,0x00000018,0x0000000b,0x00000013,0x0003003e,0x00000018,
    0x00000016,0x0004003d,0x00000008,0x0000001d,0x0000001c,0x00050041,0x00000021,0x00000022,
    0x00000020,0x0000000d,0x0004003d,0x00000008,0x00000023,0x00000022,0x00050085,0x00000008,
    0x00000024,0x0000001d,0x00000023,0x00050041,0x00000021,0x00000025,0x00000020,0x00000013,
    0x0004003d,0x00000008,0x00000026,0x00000025,0x00050081,0x00000008,0x00000027,0x00000024,
    0x00000026,0x00050051,0x00000006,0x0000002a,0x00000027,0x00000000,0x00050051,0x00000006,
    0x0000002b,0x00000027,0x00000001,0x00070050,0x00000007,0x0000002c,0x0000002a,0x0000002b,
    0x00000028,0x00000029,0x00050041,0x00000011,0x0000002d,0x0000001b,0x0000000d,0x0003003e,
    0x0000002d,0x0000002c,0x000100fd,0x00010038
};

static uint32_t __glsl_shader_frag_spv[] =
{
    0x07230203,0x00010000,0x00080001,0x0000001e,0x00000000,0x00020011,0x00000001,0x0006000b,
    0x00000001,0x4c534c47,0x6474732e,0x3035342e,0x00000000,0x0003000e,0x00000000,0x00000001,
    0x0007000f,0x00000004,0x00000004,0x6e69616d,0x00000000,0x00000009,0x0000000d,0x00030010,
    0x00000004,0x00000007,0x00030003,0x00000002,0x000001c2,0x00040005,0x00000004,0x6e69616d,
    0x00000000,0x00040005,0x00000009,0x6c6f4366,0x0000726f,0x00030005,0x0000000b,0x00000000,
    0x00050006,0x0000000b,0x00000000,0x6f6c6f43,0x00000072,0x00040006,0x0000000b,0x00000001,
    0x00005655,0x00030005,0x0000000d,0x00006e49,0x00050005,0x00000016,0x78655473,0x65727574,
    0x00000000,0x00040047,0x00000009,0x0000001e,0x00000000,0x00040047,0x0000000d,0x0000001e,
    0x00000000,0x00040047,0x00000016,0x00000022,0x00000000,0x00040047,0x00000016,0x00000021,
    0x00000000,0x00020013,0x00000002,0x00030021,0x00000003,0x00000002,0x00030016,0x00000006,
    0x00000020,0x00040017,0x00000007,0x00000006,0x00000004,0x00040020,0x00000008,0x00000003,
    0x00000007,0x0004003b,0x00000008,0x00000009,0x00000003,0x00040017,0x0000000a,0x00000006,
    0x00000002,0x0004001e,0x0000000b,0x00000007,0x0000000a,0x00040020,0x0000000c,0x00000001,
    0x0000000b,0x0004003b,0x0000000c,0x0000000d,0x00000001,0x00040015,0x0000000e,0x00000020,
    0x00000001,0x0004002b,0x0000000e,0x0000000f,0x00000000,0x00040020,0x00000010,0x00000001,
    0x00000007,0x00090019,0x00000013,0x00000006,0x00000001,0x00000000,0x00000000,0x00000000,
    0x00000001,0x00000000,0x0003001b,0x00000014,0x00000013,0x00040020,0x00000015,0x00000000,
    0x00000014,0x0004003b,0x00000015,0x00000016,0x00000000,0x0004002b,0x0000000e,0x00000018,
    0x00000001,0x00040020,0x00000019,0x00000001,0x0000000a,0x00050036,0x00000002,0x00000004,
    0x00000000,0x00000003,0x000200f8,0x00000005,0x00050041,0x00000010,0x00000011,0x0000000d,
    0x0000000f,0x0004003d,0x00000007,0x00000012,0x00000011,0x0004003d,0x00000014,0x00000017,
    0x00000016,0x00050041,0x00000019,0x0000001a,0x0000000d,0x00000018,0x0004003d,0x0000000a,
    0x0000001b,0x0000001a,0x00050057,0x00000007,0x0000001c,0x00000017,0x0000001b,0x00050085,
    0x00000007,0x0000001d,0x00000012,0x0000001c,0x0003003e,0x00000009,0x0000001d,0x000100fd,
    0x00010038
};

static uint32_t ImGui_ImplVulkan_MemoryType(VkMemoryPropertyFlags properties, uint32_t type_bits)
{
    VkPhysicalDeviceMemoryProperties prop;
    vkGetPhysicalDeviceMemoryProperties(g_PhysicalDevice, &prop);
    for (uint32_t i = 0; i < prop.memoryTypeCount; i++)
        if ((prop.memoryTypes[i].propertyFlags & properties) == properties && type_bits & (1<<i))
            return i;
    return 0xffffffff; // Unable to find memoryType
}

static void ImGui_ImplVulkan_VkResult(VkResult err)
{
    if (g_CheckVkResult)
        g_CheckVkResult(err);
}

// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data)
{
    VkResult err;
    ImGuiIO& io = ImGui::GetIO();
    if (draw_data->TotalVtxCount == 0)
        return;

    // Create the Vertex Buffer:
    size_t vertex_size = draw_data->TotalVtxCount * sizeof(ImDrawVert);
    if (!g_VertexBuffer[g_FrameIndex] || g_VertexBufferSize[g_FrameIndex] < vertex_size)
    {
        if (g_VertexBuffer[g_FrameIndex])
            vkDestroyBuffer(g_Device, g_VertexBuffer[g_FrameIndex], g_Allocator);
        if (g_VertexBufferMemory[g_FrameIndex])
            vkFreeMemory(g_Device, g_VertexBufferMemory[g_FrameIndex], g_Allocator);
        VkDeviceSize vertex_buffer_size = ((vertex_size-1) / g_BufferMemoryAlignment+1) * g_BufferMemoryAlignment;
        VkBufferCreateInfo buffer_info = {};
        buffer_info.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
        buffer_info.size = vertex_buffer_size;
        buffer_info.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
        buffer_info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
        err = vkCreateBuffer(g_Device, &buffer_info, g_Allocator, &g_VertexBuffer[g_FrameIndex]);
        ImGui_ImplVulkan_VkResult(err);
        VkMemoryRequirements req;
        vkGetBufferMemoryRequirements(g_Device, g_VertexBuffer[g_FrameIndex], &req);
        g_BufferMemoryAlignment = (g_BufferMemoryAlignment > req.alignment) ? g_BufferMemoryAlignment : req.alignment;
        VkMemoryAllocateInfo alloc_info = {};
        alloc_info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        alloc_info.allocationSize = req.size;
        alloc_info.memoryTypeIndex = ImGui_ImplVulkan_MemoryType(VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT, req.memoryTypeBits);
        err = vkAllocateMemory(g_Device, &alloc_info, g_Allocator, &g_VertexBufferMemory[g_FrameIndex]);
        ImGui_ImplVulkan_VkResult(err);
        err = vkBindBufferMemory(g_Device, g_VertexBuffer[g_FrameIndex], g_VertexBufferMemory[g_FrameIndex], 0);
        ImGui_ImplVulkan_VkResult(err);
        g_VertexBufferSize[g_FrameIndex] = vertex_buffer_size;
    }

    // Create the Index Buffer:
    size_t index_size = draw_data->TotalIdxCount * sizeof(ImDrawIdx);
    if (!g_IndexBuffer[g_FrameIndex] || g_IndexBufferSize[g_FrameIndex] < index_size)
    {
        if (g_IndexBuffer[g_FrameIndex])
            vkDestroyBuffer(g_Device, g_IndexBuffer[g_FrameIndex], g_Allocator);
        if (g_IndexBufferMemory[g_FrameIndex])
            vkFreeMemory(g_Device, g_IndexBufferMemory[g_FrameIndex], g_Allocator);
        VkDeviceSize index_buffer_size = ((index_size-1) / g_BufferMemoryAlignment+1) * g_BufferMemoryAlignment;
        VkBufferCreateInfo buffer_info = {};
        buffer_info.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
        buffer_info.size = index_buffer_size;
        buffer_info.usage = VK_BUFFER_USAGE_INDEX_BUFFER_BIT;
        buffer_info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
        err = vkCreateBuffer(g_Device, &buffer_info, g_Allocator, &g_IndexBuffer[g_FrameIndex]);
        ImGui_ImplVulkan_VkResult(err);
        VkMemoryRequirements req;
        vkGetBufferMemoryRequirements(g_Device, g_IndexBuffer[g_FrameIndex], &req);
        g_BufferMemoryAlignment = (g_BufferMemoryAlignment > req.alignment) ? g_BufferMemoryAlignment : req.alignment;
        VkMemoryAllocateInfo alloc_info = {};
        alloc_info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        alloc_info.allocationSize = req.size;
        alloc_info.memoryTypeIndex = ImGui_ImplVulkan_MemoryType(VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT, req.memoryTypeBits);
        err = vkAllocateMemory(g_Device, &alloc_info, g_Allocator, &g_IndexBufferMemory[g_FrameIndex]);
        ImGui_ImplVulkan_VkResult(err);
        err = vkBindBufferMemory(g_Device, g_IndexBuffer[g_FrameIndex], g_IndexBufferMemory[g_FrameIndex], 0);
        ImGui_ImplVulkan_VkResult(err);
        g_IndexBufferSize[g_FrameIndex] = index_buffer_size;
    }

    // Upload Vertex and index Data:
    {
        ImDrawVert* vtx_dst;
        ImDrawIdx* idx_dst;
        err = vkMapMemory(g_Device, g_VertexBufferMemory[g_FrameIndex], 0, vertex_size, 0, (void**)(&vtx_dst));
        ImGui_ImplVulkan_VkResult(err);
        err = vkMapMemory(g_Device, g_IndexBufferMemory[g_FrameIndex], 0, index_size, 0, (void**)(&idx_dst));
        ImGui_ImplVulkan_VkResult(err);
        for (int n = 0; n < draw_data->CmdListsCount; n++)
        {
            const ImDrawList* cmd_list = draw_data->CmdLists[n];
            memcpy(vtx_dst, cmd_list->VtxBuffer.Data, cmd_list->VtxBuffer.Size * sizeof(ImDrawVert));
            memcpy(idx_dst, cmd_list->IdxBuffer.Data, cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx));
            vtx_dst += cmd_list->VtxBuffer.Size;
            idx_dst += cmd_list->IdxBuffer.Size;
        }
        VkMappedMemoryRange range[2] = {};
        range[0].sType = VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE;
        range[0].memory = g_VertexBufferMemory[g_FrameIndex];
        range[0].size = VK_WHOLE_SIZE;
        range[1].sType = VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE;
        range[1].memory = g_IndexBufferMemory[g_FrameIndex];
        range[1].size = VK_WHOLE_SIZE;
        err = vkFlushMappedMemoryRanges(g_Device, 2, range);
        ImGui_ImplVulkan_VkResult(err);
        vkUnmapMemory(g_Device, g_VertexBufferMemory[g_FrameIndex]);
        vkUnmapMemory(g_Device, g_IndexBufferMemory[g_FrameIndex]);
    }

    // Bind pipeline and descriptor sets:
    {
        vkCmdBindPipeline(g_CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, g_Pipeline);
        VkDescriptorSet desc_set[1] = {g_DescriptorSet};
        vkCmdBindDescriptorSets(g_CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, g_PipelineLayout, 0, 1, desc_set, 0, NULL);
    }

    // Bind Vertex And Index Buffer:
    {
        VkBuffer vertex_buffers[1] = {g_VertexBuffer[g_FrameIndex]};
        VkDeviceSize vertex_offset[1] = {0};
        vkCmdBindVertexBuffers(g_CommandBuffer, 0, 1, vertex_buffers, vertex_offset);
        vkCmdBindIndexBuffer(g_CommandBuffer, g_IndexBuffer[g_FrameIndex], 0, VK_INDEX_TYPE_UINT16);
    }

    // Setup viewport:
    {
        VkViewport viewport;
        viewport.x = 0;
        viewport.y = 0;
        viewport.width = io.DisplaySize.x;
        viewport.height = io.DisplaySize.y;
        viewport.minDepth = 0.0f;
        viewport.maxDepth = 1.0f;
        vkCmdSetViewport(g_CommandBuffer, 0, 1, &viewport);
    }

    // Setup scale and translation:
    // (Our visible imgui space lies from io.DisplayPos (top left) to io.DisplayPos+io.DisplaySize (bottom right). io.DisplayPos is typically (0,0) for single viewport applications.)
    {
        float scale[2];
        scale[0] = 2.0f / io.DisplaySize.x;
        scale[1] = 2.0f / io.DisplaySize.y;
        float translate[2];
        translate[0] = -1.0f - io.DisplayPos.x * scale[0];
        translate[1] = -1.0f - io.DisplayPos.y * scale[1];
        vkCmdPushConstants(g_CommandBuffer, g_PipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, sizeof(float) * 0, sizeof(float) * 2, scale);
        vkCmdPushConstants(g_CommandBuffer, g_PipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, sizeof(float) * 2, sizeof(float) * 2, translate);
    }

    // Render the command lists:
    int vtx_offset = 0;
    int idx_offset = 0;
    for (int n = 0; n < draw_data->CmdListsCount; n++)
    {
        const ImDrawList* cmd_list = draw_data->CmdLists[n];
        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
        {
            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
            if (pcmd->UserCallback)
            {
                pcmd->UserCallback(cmd_list, pcmd);
            }
            else
            {
                // Apply scissor/clipping rectangle
                // FIXME: We could clamp width/height based on clamped min/max values.
                VkRect2D scissor;
                scissor.offset.x = (int32_t)(pcmd->ClipRect.x - io.DisplayPos.x) > 0 ? (int32_t)(pcmd->ClipRect.x - io.DisplayPos.y) : 0;
                scissor.offset.y = (int32_t)(pcmd->ClipRect.y - io.DisplayPos.y) > 0 ? (int32_t)(pcmd->ClipRect.y - io.DisplayPos.y) : 0;
                scissor.extent.width = (uint32_t)(pcmd->ClipRect.z - pcmd->ClipRect.x);
                scissor.extent.height = (uint32_t)(pcmd->ClipRect.w - pcmd->ClipRect.y + 1); // FIXME: Why +1 here?
                vkCmdSetScissor(g_CommandBuffer, 0, 1, &scissor);
                
                // Draw
                vkCmdDrawIndexed(g_CommandBuffer, pcmd->ElemCount, 1, idx_offset, vtx_offset, 0);
            }
            idx_offset += pcmd->ElemCount;
        }
        vtx_offset += cmd_list->VtxBuffer.Size;
    }
}

bool ImGui_ImplVulkan_CreateFontsTexture(VkCommandBuffer command_buffer)
{
    ImGuiIO& io = ImGui::GetIO();

    unsigned char* pixels;
    int width, height;
    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
    size_t upload_size = width*height*4*sizeof(char);

    VkResult err;

    // Create the Image:
    {
        VkImageCreateInfo info = {};
        info.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
        info.imageType = VK_IMAGE_TYPE_2D;
        info.format = VK_FORMAT_R8G8B8A8_UNORM;
        info.extent.width = width;
        info.extent.height = height;
        info.extent.depth = 1;
        info.mipLevels = 1;
        info.arrayLayers = 1;
        info.samples = VK_SAMPLE_COUNT_1_BIT;
        info.tiling = VK_IMAGE_TILING_OPTIMAL;
        info.usage = VK_IMAGE_USAGE_SAMPLED_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
        info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
        info.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
        err = vkCreateImage(g_Device, &info, g_Allocator, &g_FontImage);
        ImGui_ImplVulkan_VkResult(err);
        VkMemoryRequirements req;
        vkGetImageMemoryRequirements(g_Device, g_FontImage, &req);
        VkMemoryAllocateInfo alloc_info = {};
        alloc_info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        alloc_info.allocationSize = req.size;
        alloc_info.memoryTypeIndex = ImGui_ImplVulkan_MemoryType(VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT, req.memoryTypeBits);
        err = vkAllocateMemory(g_Device, &alloc_info, g_Allocator, &g_FontMemory);
        ImGui_ImplVulkan_VkResult(err);
        err = vkBindImageMemory(g_Device, g_FontImage, g_FontMemory, 0);
        ImGui_ImplVulkan_VkResult(err);
    }

    // Create the Image View:
    {
        VkImageViewCreateInfo info = {};
        info.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
        info.image = g_FontImage;
        info.viewType = VK_IMAGE_VIEW_TYPE_2D;
        info.format = VK_FORMAT_R8G8B8A8_UNORM;
        info.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        info.subresourceRange.levelCount = 1;
        info.subresourceRange.layerCount = 1;
        err = vkCreateImageView(g_Device, &info, g_Allocator, &g_FontView);
        ImGui_ImplVulkan_VkResult(err);
    }

    // Update the Descriptor Set:
    {
        VkDescriptorImageInfo desc_image[1] = {};
        desc_image[0].sampler = g_FontSampler;
        desc_image[0].imageView = g_FontView;
        desc_image[0].imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
        VkWriteDescriptorSet write_desc[1] = {};
        write_desc[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
        write_desc[0].dstSet = g_DescriptorSet;
        write_desc[0].descriptorCount = 1;
        write_desc[0].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
        write_desc[0].pImageInfo = desc_image;
        vkUpdateDescriptorSets(g_Device, 1, write_desc, 0, NULL);
    }

    // Create the Upload Buffer:
    {
        VkBufferCreateInfo buffer_info = {};
        buffer_info.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
        buffer_info.size = upload_size;
        buffer_info.usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT;
        buffer_info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
        err = vkCreateBuffer(g_Device, &buffer_info, g_Allocator, &g_UploadBuffer);
        ImGui_ImplVulkan_VkResult(err);
        VkMemoryRequirements req;
        vkGetBufferMemoryRequirements(g_Device, g_UploadBuffer, &req);
        g_BufferMemoryAlignment = (g_BufferMemoryAlignment > req.alignment) ? g_BufferMemoryAlignment : req.alignment;
        VkMemoryAllocateInfo alloc_info = {};
        alloc_info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        alloc_info.allocationSize = req.size;
        alloc_info.memoryTypeIndex = ImGui_ImplVulkan_MemoryType(VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT, req.memoryTypeBits);
        err = vkAllocateMemory(g_Device, &alloc_info, g_Allocator, &g_UploadBufferMemory);
        ImGui_ImplVulkan_VkResult(err);
        err = vkBindBufferMemory(g_Device, g_UploadBuffer, g_UploadBufferMemory, 0);
        ImGui_ImplVulkan_VkResult(err);
    }

    // Upload to Buffer:
    {
        char* map = NULL;
        err = vkMapMemory(g_Device, g_UploadBufferMemory, 0, upload_size, 0, (void**)(&map));
        ImGui_ImplVulkan_VkResult(err);
        memcpy(map, pixels, upload_size);
        VkMappedMemoryRange range[1] = {};
        range[0].sType = VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE;
        range[0].memory = g_UploadBufferMemory;
        range[0].size = upload_size;
        err = vkFlushMappedMemoryRanges(g_Device, 1, range);
        ImGui_ImplVulkan_VkResult(err);
        vkUnmapMemory(g_Device, g_UploadBufferMemory);
    }

    // Copy to Image:
    {
        VkImageMemoryBarrier copy_barrier[1] = {};
        copy_barrier[0].sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
        copy_barrier[0].dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
        copy_barrier[0].oldLayout = VK_IMAGE_LAYOUT_UNDEFINED;
        copy_barrier[0].newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
        copy_barrier[0].srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
        copy_barrier[0].dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
        copy_barrier[0].image = g_FontImage;
        copy_barrier[0].subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        copy_barrier[0].subresourceRange.levelCount = 1;
        copy_barrier[0].subresourceRange.layerCount = 1;
        vkCmdPipelineBarrier(command_buffer, VK_PIPELINE_STAGE_HOST_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, NULL, 0, NULL, 1, copy_barrier);

        VkBufferImageCopy region = {};
        region.imageSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        region.imageSubresource.layerCount = 1;
        region.imageExtent.width = width;
        region.imageExtent.height = height;
        region.imageExtent.depth = 1;
        vkCmdCopyBufferToImage(command_buffer, g_UploadBuffer, g_FontImage, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &region);

        VkImageMemoryBarrier use_barrier[1] = {};
        use_barrier[0].sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
        use_barrier[0].srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
        use_barrier[0].dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
        use_barrier[0].oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
        use_barrier[0].newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
        use_barrier[0].srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
        use_barrier[0].dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
        use_barrier[0].image = g_FontImage;
        use_barrier[0].subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        use_barrier[0].subresourceRange.levelCount = 1;
        use_barrier[0].subresourceRange.layerCount = 1;
        vkCmdPipelineBarrier(command_buffer, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, NULL, 0, NULL, 1, use_barrier);
    }

    // Store our identifier
    io.Fonts->TexID = (void *)(intptr_t)g_FontImage;

    return true;
}

bool ImGui_ImplVulkan_CreateDeviceObjects()
{
    VkResult err;
    VkShaderModule vert_module;
    VkShaderModule frag_module;

    // Create The Shader Modules:
    {
        VkShaderModuleCreateInfo vert_info = {};
        vert_info.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
        vert_info.codeSize = sizeof(__glsl_shader_vert_spv);
        vert_info.pCode = (uint32_t*)__glsl_shader_vert_spv;
        err = vkCreateShaderModule(g_Device, &vert_info, g_Allocator, &vert_module);
        ImGui_ImplVulkan_VkResult(err);
        VkShaderModuleCreateInfo frag_info = {};
        frag_info.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO;
        frag_info.codeSize = sizeof(__glsl_shader_frag_spv);
        frag_info.pCode = (uint32_t*)__glsl_shader_frag_spv;
        err = vkCreateShaderModule(g_Device, &frag_info, g_Allocator, &frag_module);
        ImGui_ImplVulkan_VkResult(err);
    }

    if (!g_FontSampler)
    {
        VkSamplerCreateInfo info = {};
        info.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
        info.magFilter = VK_FILTER_LINEAR;
        info.minFilter = VK_FILTER_LINEAR;
        info.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
        info.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;
        info.addressModeV = VK_SAMPLER_ADDRESS_MODE_REPEAT;
        info.addressModeW = VK_SAMPLER_ADDRESS_MODE_REPEAT;
        info.minLod = -1000;
        info.maxLod = 1000;
        info.maxAnisotropy = 1.0f;
        err = vkCreateSampler(g_Device, &info, g_Allocator, &g_FontSampler);
        ImGui_ImplVulkan_VkResult(err);
    }

    if (!g_DescriptorSetLayout)
    {
        VkSampler sampler[1] = {g_FontSampler};
        VkDescriptorSetLayoutBinding binding[1] = {};
        binding[0].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
        binding[0].descriptorCount = 1;
        binding[0].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
        binding[0].pImmutableSamplers = sampler;
        VkDescriptorSetLayoutCreateInfo info = {};
        info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
        info.bindingCount = 1;
        info.pBindings = binding;
        err = vkCreateDescriptorSetLayout(g_Device, &info, g_Allocator, &g_DescriptorSetLayout);
        ImGui_ImplVulkan_VkResult(err);
    }

    // Create Descriptor Set:
    {
        VkDescriptorSetAllocateInfo alloc_info = {};
        alloc_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
        alloc_info.descriptorPool = g_DescriptorPool;
        alloc_info.descriptorSetCount = 1;
        alloc_info.pSetLayouts = &g_DescriptorSetLayout;
        err = vkAllocateDescriptorSets(g_Device, &alloc_info, &g_DescriptorSet);
        ImGui_ImplVulkan_VkResult(err);
    }

    if (!g_PipelineLayout)
    {
        VkPushConstantRange push_constants[1] = {};
        push_constants[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
        push_constants[0].offset = sizeof(float) * 0;
        push_constants[0].size = sizeof(float) * 4;
        VkDescriptorSetLayout set_layout[1] = {g_DescriptorSetLayout};
        VkPipelineLayoutCreateInfo layout_info = {};
        layout_info.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
        layout_info.setLayoutCount = 1;
        layout_info.pSetLayouts = set_layout;
        layout_info.pushConstantRangeCount = 1;
        layout_info.pPushConstantRanges = push_constants;
        err = vkCreatePipelineLayout(g_Device, &layout_info, g_Allocator, &g_PipelineLayout);
        ImGui_ImplVulkan_VkResult(err);
    }

    VkPipelineShaderStageCreateInfo stage[2] = {};
    stage[0].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
    stage[0].stage = VK_SHADER_STAGE_VERTEX_BIT;
    stage[0].module = vert_module;
    stage[0].pName = "main";
    stage[1].sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
    stage[1].stage = VK_SHADER_STAGE_FRAGMENT_BIT;
    stage[1].module = frag_module;
    stage[1].pName = "main";

    VkVertexInputBindingDescription binding_desc[1] = {};
    binding_desc[0].stride = sizeof(ImDrawVert);
    binding_desc[0].inputRate = VK_VERTEX_INPUT_RATE_VERTEX;

    VkVertexInputAttributeDescription attribute_desc[3] = {};
    attribute_desc[0].location = 0;
    attribute_desc[0].binding = binding_desc[0].binding;
    attribute_desc[0].format = VK_FORMAT_R32G32_SFLOAT;
    attribute_desc[0].offset = (size_t)(&((ImDrawVert*)0)->pos);
    attribute_desc[1].location = 1;
    attribute_desc[1].binding = binding_desc[0].binding;
    attribute_desc[1].format = VK_FORMAT_R32G32_SFLOAT;
    attribute_desc[1].offset = (size_t)(&((ImDrawVert*)0)->uv);
    attribute_desc[2].location = 2;
    attribute_desc[2].binding = binding_desc[0].binding;
    attribute_desc[2].format = VK_FORMAT_R8G8B8A8_UNORM;
    attribute_desc[2].offset = (size_t)(&((ImDrawVert*)0)->col);

    VkPipelineVertexInputStateCreateInfo vertex_info = {};
    vertex_info.sType = VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
    vertex_info.vertexBindingDescriptionCount = 1;
    vertex_info.pVertexBindingDescriptions = binding_desc;
    vertex_info.vertexAttributeDescriptionCount = 3;
    vertex_info.pVertexAttributeDescriptions = attribute_desc;

    VkPipelineInputAssemblyStateCreateInfo ia_info = {};
    ia_info.sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO;
    ia_info.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;

    VkPipelineViewportStateCreateInfo viewport_info = {};
    viewport_info.sType = VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO;
    viewport_info.viewportCount = 1;
    viewport_info.scissorCount = 1;

    VkPipelineRasterizationStateCreateInfo raster_info = {};
    raster_info.sType = VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO;
    raster_info.polygonMode = VK_POLYGON_MODE_FILL;
    raster_info.cullMode = VK_CULL_MODE_NONE;
    raster_info.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE;
    raster_info.lineWidth = 1.0f;

    VkPipelineMultisampleStateCreateInfo ms_info = {};
    ms_info.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
    ms_info.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;

    VkPipelineColorBlendAttachmentState color_attachment[1] = {};
    color_attachment[0].blendEnable = VK_TRUE;
    color_attachment[0].srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA;
    color_attachment[0].dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
    color_attachment[0].colorBlendOp = VK_BLEND_OP_ADD;
    color_attachment[0].srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
    color_attachment[0].dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
    color_attachment[0].alphaBlendOp = VK_BLEND_OP_ADD;
    color_attachment[0].colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;

    VkPipelineDepthStencilStateCreateInfo depth_info = {};
    depth_info.sType = VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO;

    VkPipelineColorBlendStateCreateInfo blend_info = {};
    blend_info.sType = VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO;
    blend_info.attachmentCount = 1;
    blend_info.pAttachments = color_attachment;

    VkDynamicState dynamic_states[2] = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
    VkPipelineDynamicStateCreateInfo dynamic_state = {};
    dynamic_state.sType = VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO;
    dynamic_state.dynamicStateCount = 2;
    dynamic_state.pDynamicStates = dynamic_states;

    VkGraphicsPipelineCreateInfo info = {};
    info.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
    info.flags = g_PipelineCreateFlags;
    info.stageCount = 2;
    info.pStages = stage;
    info.pVertexInputState = &vertex_info;
    info.pInputAssemblyState = &ia_info;
    info.pViewportState = &viewport_info;
    info.pRasterizationState = &raster_info;
    info.pMultisampleState = &ms_info;
    info.pDepthStencilState = &depth_info;
    info.pColorBlendState = &blend_info;
    info.pDynamicState = &dynamic_state;
    info.layout = g_PipelineLayout;
    info.renderPass = g_RenderPass;
    err = vkCreateGraphicsPipelines(g_Device, g_PipelineCache, 1, &info, g_Allocator, &g_Pipeline);
    ImGui_ImplVulkan_VkResult(err);

    vkDestroyShaderModule(g_Device, vert_module, g_Allocator);
    vkDestroyShaderModule(g_Device, frag_module, g_Allocator);

    return true;
}

void    ImGui_ImplVulkan_InvalidateFontUploadObjects()
{
    if (g_UploadBuffer)
    {
        vkDestroyBuffer(g_Device, g_UploadBuffer, g_Allocator);
        g_UploadBuffer = VK_NULL_HANDLE;
    }
    if (g_UploadBufferMemory)
    {
        vkFreeMemory(g_Device, g_UploadBufferMemory, g_Allocator);
        g_UploadBufferMemory = VK_NULL_HANDLE;
    }
}

void    ImGui_ImplVulkan_InvalidateDeviceObjects()
{
    ImGui_ImplVulkan_InvalidateFontUploadObjects();

    for (int i = 0; i < IMGUI_VK_QUEUED_FRAMES; i++)
    {
        if (g_VertexBuffer[i])          { vkDestroyBuffer(g_Device, g_VertexBuffer[i], g_Allocator); g_VertexBuffer[i] = VK_NULL_HANDLE; }
        if (g_VertexBufferMemory[i])    { vkFreeMemory(g_Device, g_VertexBufferMemory[i], g_Allocator); g_VertexBufferMemory[i] = VK_NULL_HANDLE; }
        if (g_IndexBuffer[i])           { vkDestroyBuffer(g_Device, g_IndexBuffer[i], g_Allocator); g_IndexBuffer[i] = VK_NULL_HANDLE; }
        if (g_IndexBufferMemory[i])     { vkFreeMemory(g_Device, g_IndexBufferMemory[i], g_Allocator); g_IndexBufferMemory[i] = VK_NULL_HANDLE; }
    }

    if (g_FontView)             { vkDestroyImageView(g_Device, g_FontView, g_Allocator); g_FontView = VK_NULL_HANDLE; }
    if (g_FontImage)            { vkDestroyImage(g_Device, g_FontImage, g_Allocator); g_FontImage = VK_NULL_HANDLE; }
    if (g_FontMemory)           { vkFreeMemory(g_Device, g_FontMemory, g_Allocator); g_FontMemory = VK_NULL_HANDLE; }
    if (g_FontSampler)          { vkDestroySampler(g_Device, g_FontSampler, g_Allocator); g_FontSampler = VK_NULL_HANDLE; }
    if (g_DescriptorSetLayout)  { vkDestroyDescriptorSetLayout(g_Device, g_DescriptorSetLayout, g_Allocator); g_DescriptorSetLayout = VK_NULL_HANDLE; }
    if (g_PipelineLayout)       { vkDestroyPipelineLayout(g_Device, g_PipelineLayout, g_Allocator); g_PipelineLayout = VK_NULL_HANDLE; }
    if (g_Pipeline)             { vkDestroyPipeline(g_Device, g_Pipeline, g_Allocator); g_Pipeline = VK_NULL_HANDLE; }
}

bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo *init_data)
{
    g_Allocator = init_data->Allocator;
    g_PhysicalDevice = init_data->PhysicalDevice;
    g_Device = init_data->Device;
    g_RenderPass = init_data->RenderPass;
    g_PipelineCache = init_data->PipelineCache;
    g_DescriptorPool = init_data->DescriptorPool;
    g_CheckVkResult = init_data->CheckVkResultFn;

    ImGuiIO& io = ImGui::GetIO();
    ImGui_ImplVulkan_CreateDeviceObjects();
    if (io.ConfigFlags & ImGuiConfigFlags_MultiViewports)
        ImGui_ImplVulkan_InitPlatformInterface();

    return true;
}

void ImGui_ImplVulkan_Shutdown()
{
    ImGui_ImplVulkan_ShutdownPlatformInterface();
    ImGui_ImplVulkan_InvalidateDeviceObjects();
}

void ImGui_ImplVulkan_NewFrame()
{
}

void ImGui_ImplVulkan_Render(VkCommandBuffer command_buffer)
{
    g_CommandBuffer = command_buffer;
    ImGui::Render();
    ImGui_ImplVulkan_RenderDrawData(ImGui::GetDrawData());
    g_CommandBuffer = VK_NULL_HANDLE;
    g_FrameIndex = (g_FrameIndex + 1) % IMGUI_VK_QUEUED_FRAMES;
}

//-------------------------------------------------------------------------
// Miscellaneous Vulkan Helpers
// (Those are currently not strictly needed by the binding, but will be once if we support multi-viewports)
//-------------------------------------------------------------------------

#include <stdlib.h> // malloc

VkSurfaceFormatKHR ImGui_ImplVulkan_SelectSurfaceFormat(VkPhysicalDevice physical_device, VkSurfaceKHR surface, const VkFormat* request_formats, int request_formats_count, VkColorSpaceKHR request_color_space)
{
    IM_ASSERT(request_formats != NULL);
    IM_ASSERT(request_formats_count > 0);

    // Per Spec Format and View Format are expected to be the same unless VK_IMAGE_CREATE_MUTABLE_BIT was set at image creation
    // Assuming that the default behavior is without setting this bit, there is no need for separate Swapchain image and image view format
    // Additionally several new color spaces were introduced with Vulkan Spec v1.0.40,
    // hence we must make sure that a format with the mostly available color space, VK_COLOR_SPACE_SRGB_NONLINEAR_KHR, is found and used.
    uint32_t avail_count;
    vkGetPhysicalDeviceSurfaceFormatsKHR(physical_device, surface, &avail_count, NULL);
    ImVector<VkSurfaceFormatKHR> avail_format;
    avail_format.resize((int)avail_count);
    vkGetPhysicalDeviceSurfaceFormatsKHR(physical_device, surface, &avail_count, avail_format.Data);

    // First check if only one format, VK_FORMAT_UNDEFINED, is available, which would imply that any format is available
    if (avail_count == 1)
    {
        if (avail_format[0].format == VK_FORMAT_UNDEFINED)
        {
            VkSurfaceFormatKHR ret;
            ret.format = request_formats[0];
            ret.colorSpace = request_color_space;
            return ret;
        }
        else
        {
            // No point in searching another format
            return avail_format[0];
        }
    }
    else
    {
        // Request several formats, the first found will be used 
        for (int request_i = 0; request_i < request_formats_count; request_i++)
            for (uint32_t avail_i = 0; avail_i < avail_count; avail_i++)
                if (avail_format[avail_i].format == request_formats[request_i] && avail_format[avail_i].colorSpace == request_color_space)
                    return avail_format[avail_i];

        // If none of the requested image formats could be found, use the first available
        return avail_format[0];
    }
}

VkPresentModeKHR ImGui_ImplVulkan_SelectPresentMode(VkPhysicalDevice physical_device, VkSurfaceKHR surface, const VkPresentModeKHR* request_modes, int request_modes_count)
{
    IM_ASSERT(request_modes != NULL);
    IM_ASSERT(request_modes_count > 0);

    // Request a certain mode and confirm that it is available. If not use VK_PRESENT_MODE_FIFO_KHR which is mandatory
    uint32_t avail_count = 0;
    vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, surface, &avail_count, NULL);
    ImVector<VkPresentModeKHR> avail_modes;
    avail_modes.resize((int)avail_count);
    vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, surface, &avail_count, avail_modes.Data);
    for (int request_i = 0; request_i < request_modes_count; request_i++)
        for (uint32_t avail_i = 0; avail_i < avail_count; avail_i++)
            if (request_modes[request_i] == avail_modes[avail_i])
                return request_modes[request_i];

    return VK_PRESENT_MODE_FIFO_KHR; // Always available
}

// --------------------------------------------------------------------------------------------------------
// Platform Windows (OPTIONAL/EXPERIMENTAL)
// --------------------------------------------------------------------------------------------------------

#include "imgui_internal.h"     // ImGuiViewport

struct ImGuiPlatformDataVulkan
{
    // store swap chain, render target/frame buffer, etc.

    ImGuiPlatformDataVulkan() { }
    ~ImGuiPlatformDataVulkan() { }
};

static void ImGui_ImplVulkan_CreateViewport(ImGuiViewport* viewport)
{
    ImGuiPlatformDataVulkan* data = IM_NEW(ImGuiPlatformDataVulkan)();
    viewport->RendererUserData = data;

    // FIXME-PLATFORM
    //HWND hwnd = (HWND)viewport->PlatformHandle;
    //IM_ASSERT(hwnd != 0);

    //...
}

static void ImGui_ImplVulkan_DestroyViewport(ImGuiViewport* viewport)
{
    if (ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData)
    {
        //...
        IM_DELETE(data);
    }
    viewport->RendererUserData = NULL;
}

static void ImGui_ImplVulkan_ResizeViewport(ImGuiViewport* viewport, int w, int h)
{
    ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData;
    //...
    (void)data;
    (void)w;
    (void)h;
}

static void ImGui_ImplVulkan_RenderViewport(ImGuiViewport* viewport)
{
    ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData;
    ImVec4 clear_color = ImGui::GetStyle().Colors[ImGuiCol_WindowBg]; // FIXME-PLATFORM
    clear_color.w = 1.0f;

    (void)data;
    // clear
    // call ImGui_ImplVulkan_RenderDrawData(&viewport->DrawData)
}

static void ImGui_ImplVulkan_SwapBuffers(ImGuiViewport* viewport)
{
    ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData;
    (void)data;
    //...
}

void ImGui_ImplVulkan_InitPlatformInterface()
{
    ImGuiIO& io = ImGui::GetIO();
    io.RendererInterface.CreateViewport = ImGui_ImplVulkan_CreateViewport;
    io.RendererInterface.DestroyViewport = ImGui_ImplVulkan_DestroyViewport;
    io.RendererInterface.ResizeViewport = ImGui_ImplVulkan_ResizeViewport;
    io.RendererInterface.RenderViewport = ImGui_ImplVulkan_RenderViewport;
    io.RendererInterface.SwapBuffers = ImGui_ImplVulkan_SwapBuffers;
}

void ImGui_ImplVulkan_ShutdownPlatformInterface()
{
    ImGuiIO& io = ImGui::GetIO();
    memset(&io.RendererInterface, 0, sizeof(io.RendererInterface));
}