aurora/lib/imgui_impl_wgpu.cpp

// dear imgui: Renderer for WebGPU
// This needs to be used along with a Platform Binding (e.g. GLFW)
// (Please note that WebGPU is currently experimental, will not run on non-beta browsers, and may break.)

// Implemented features:
//  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.

// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
//  2022-11-24: Fixed validation error with default depth buffer settings.
//  2022-11-10: Fixed rendering when a depth buffer is enabled. Added 'WGPUTextureFormat depth_format' parameter to ImGui_ImplWGPU_Init().
//  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
//  2021-11-29: Passing explicit buffer sizes to wgpuRenderPassEncoderSetVertexBuffer()/wgpuRenderPassEncoderSetIndexBuffer().
//  2021-08-24: Fixed for latest specs.
//  2021-05-24: Add support for draw_data->FramebufferScale.
//  2021-05-19: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
//  2021-05-16: Update to latest WebGPU specs (compatible with Emscripten 2.0.20 and Chrome Canary 92).
//  2021-02-18: Change blending equation to preserve alpha in output buffer.
//  2021-01-28: Initial version.

#include "imgui.h"
#include "imgui_impl_wgpu.h"
#include <limits.h>
#include <webgpu/webgpu.h>

// Dear ImGui prototypes from imgui_internal.h
extern ImGuiID ImHashData(const void* data_p, size_t data_size, ImU32 seed = 0);

// WebGPU data
static WGPUDevice               g_wgpuDevice = nullptr;
static WGPUQueue                g_defaultQueue = nullptr;
static WGPUTextureFormat        g_renderTargetFormat = WGPUTextureFormat_Undefined;
static WGPUTextureFormat        g_depthStencilFormat = WGPUTextureFormat_Undefined;
static WGPURenderPipeline       g_pipelineState = nullptr;

struct RenderResources
{
  WGPUTexture         FontTexture;            // Font texture
  WGPUTextureView     FontTextureView;        // Texture view for font texture
  WGPUSampler         Sampler;                // Sampler for the font texture
  WGPUBuffer          Uniforms;               // Shader uniforms
  WGPUBindGroup       CommonBindGroup;        // Resources bind-group to bind the common resources to pipeline
  ImGuiStorage        ImageBindGroups;        // Resources bind-group to bind the font/image resources to pipeline (this is a key->value map)
  WGPUBindGroup       ImageBindGroup;         // Default font-resource of Dear ImGui
  WGPUBindGroupLayout ImageBindGroupLayout;   // Cache layout used for the image bind group. Avoids allocating unnecessary JS objects when working with WebASM
};
static RenderResources  g_resources;

struct FrameResources
{
  WGPUBuffer  IndexBuffer;
  WGPUBuffer  VertexBuffer;
  ImDrawIdx*  IndexBufferHost;
  ImDrawVert* VertexBufferHost;
  int         IndexBufferSize;
  int         VertexBufferSize;
};
static FrameResources*  g_pFrameResources = nullptr;
static unsigned int     g_numFramesInFlight = 0;
static unsigned int     g_frameIndex = UINT_MAX;

struct Uniforms
{
  float MVP[4][4];
};

//-----------------------------------------------------------------------------
// SHADERS
//-----------------------------------------------------------------------------

static const char* __wgsl_shader = R"(
struct Uniforms
{
  mvp: mat4x4<f32>,
}

@group(0) @binding(0) var<uniform> uniforms: Uniforms;
@group(0) @binding(1) var samp: sampler;
@group(1) @binding(0) var tex: texture_2d<f32>;

struct VertexOutput
{
  @location(0) color: vec4<f32>,
  @location(1) uv: vec2<f32>,
  @builtin(position) pos: vec4<f32>,
}

@vertex
fn vs_main(
  @location(0) pos: vec2<f32>,
  @location(1) uv: vec2<f32>,
  @location(2) color: vec4<f32>,
) -> VertexOutput
{
  var out: VertexOutput;
  out.color = color;
  out.uv = uv;
  out.pos = uniforms.mvp * vec4<f32>(pos.x, pos.y, 0.0, 1.0);
  return out;
}

@fragment
fn fs_main(in: VertexOutput) -> @location(0) vec4<f32>
{
  return in.color * textureSample(tex, samp, in.uv.xy);
}
)";

static void SafeRelease(ImDrawIdx*& res)
{
  if (res)
    delete[] res;
  res = nullptr;
}
static void SafeRelease(ImDrawVert*& res)
{
  if (res)
    delete[] res;
  res = nullptr;
}
static void SafeRelease(WGPUBindGroupLayout& res)
{
  if (res)
    wgpuBindGroupLayoutRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPUBindGroup& res)
{
  if (res)
    wgpuBindGroupRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPUBuffer& res)
{
  if (res)
    wgpuBufferRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPURenderPipeline& res)
{
  if (res)
    wgpuRenderPipelineRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPUSampler& res)
{
  if (res)
    wgpuSamplerRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPUShaderModule& res)
{
  if (res)
    wgpuShaderModuleRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPUTextureView& res)
{
  if (res)
    wgpuTextureViewRelease(res);
  res = nullptr;
}
static void SafeRelease(WGPUTexture& res)
{
  if (res)
    wgpuTextureRelease(res);
  res = nullptr;
}

static void SafeRelease(RenderResources& res)
{
  SafeRelease(res.FontTexture);
  SafeRelease(res.FontTextureView);
  SafeRelease(res.Sampler);
  SafeRelease(res.Uniforms);
  SafeRelease(res.CommonBindGroup);
  SafeRelease(res.ImageBindGroup);
  SafeRelease(res.ImageBindGroupLayout);
};

static void SafeRelease(FrameResources& res)
{
  SafeRelease(res.IndexBuffer);
  SafeRelease(res.VertexBuffer);
  SafeRelease(res.IndexBufferHost);
  SafeRelease(res.VertexBufferHost);
}

static WGPUShaderModule ImGui_ImplWGPU_CreateShaderModule(const char* source)
{
  WGPUShaderModuleWGSLDescriptor wgsl_desc = {};
  wgsl_desc.chain.sType = WGPUSType_ShaderModuleWGSLDescriptor;
  wgsl_desc.source = source;

  WGPUShaderModuleDescriptor desc = {};
  desc.nextInChain = reinterpret_cast<WGPUChainedStruct*>(&wgsl_desc);

  return wgpuDeviceCreateShaderModule(g_wgpuDevice, &desc);
}

static WGPUBindGroup ImGui_ImplWGPU_CreateImageBindGroup(WGPUBindGroupLayout layout, WGPUTextureView texture)
{
  WGPUBindGroupEntry image_bg_entries[] = { { nullptr, 0, 0, 0, 0, 0, texture } };

  WGPUBindGroupDescriptor image_bg_descriptor = {};
  image_bg_descriptor.layout = layout;
  image_bg_descriptor.entryCount = sizeof(image_bg_entries) / sizeof(WGPUBindGroupEntry);
  image_bg_descriptor.entries = image_bg_entries;
  return wgpuDeviceCreateBindGroup(g_wgpuDevice, &image_bg_descriptor);
}

static void ImGui_ImplWGPU_SetupRenderState(ImDrawData* draw_data, WGPURenderPassEncoder ctx, FrameResources* fr)
{
  // Setup orthographic projection matrix into our constant buffer
  // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
  {
    float L = draw_data->DisplayPos.x;
    float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
    float T = draw_data->DisplayPos.y;
    float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
    float mvp[4][4] =
        {
            { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
            { 0.0f,         2.0f/(T-B),     0.0f,       0.0f },
            { 0.0f,         0.0f,           0.5f,       0.0f },
            { (R+L)/(L-R),  (T+B)/(B-T),    0.5f,       1.0f },
        };
    wgpuQueueWriteBuffer(g_defaultQueue, g_resources.Uniforms, 0, mvp, sizeof(mvp));
  }

  // Setup viewport
  wgpuRenderPassEncoderSetViewport(ctx, 0, 0, draw_data->FramebufferScale.x * draw_data->DisplaySize.x, draw_data->FramebufferScale.y * draw_data->DisplaySize.y, 0, 1);

  // Bind shader and vertex buffers
  wgpuRenderPassEncoderSetVertexBuffer(ctx, 0, fr->VertexBuffer, 0, fr->VertexBufferSize * sizeof(ImDrawVert));
  wgpuRenderPassEncoderSetIndexBuffer(ctx, fr->IndexBuffer, sizeof(ImDrawIdx) == 2 ? WGPUIndexFormat_Uint16 : WGPUIndexFormat_Uint32, 0, fr->IndexBufferSize * sizeof(ImDrawIdx));
  wgpuRenderPassEncoderSetPipeline(ctx, g_pipelineState);
  wgpuRenderPassEncoderSetBindGroup(ctx, 0, g_resources.CommonBindGroup, 0, nullptr);

  // Setup blend factor
  WGPUColor blend_color = { 0.f, 0.f, 0.f, 0.f };
  wgpuRenderPassEncoderSetBlendConstant(ctx, &blend_color);
}

// Render function
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder pass_encoder)
{
  // Avoid rendering when minimized
  if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
    return;

  // FIXME: Assuming that this only gets called once per frame!
  // If not, we can't just re-allocate the IB or VB, we'll have to do a proper allocator.
  g_frameIndex = g_frameIndex + 1;
  FrameResources* fr = &g_pFrameResources[g_frameIndex % g_numFramesInFlight];

  // Create and grow vertex/index buffers if needed
  if (fr->VertexBuffer == nullptr || fr->VertexBufferSize < draw_data->TotalVtxCount)
  {
    if (fr->VertexBuffer)
    {
      wgpuBufferDestroy(fr->VertexBuffer);
      wgpuBufferRelease(fr->VertexBuffer);
    }
    SafeRelease(fr->VertexBufferHost);
    fr->VertexBufferSize = draw_data->TotalVtxCount + 5000;

    WGPUBufferDescriptor vb_desc =
        {
            nullptr,
            "Dear ImGui Vertex buffer",
            WGPUBufferUsage_CopyDst | WGPUBufferUsage_Vertex,
            fr->VertexBufferSize * sizeof(ImDrawVert),
            false
        };
    fr->VertexBuffer = wgpuDeviceCreateBuffer(g_wgpuDevice, &vb_desc);
    if (!fr->VertexBuffer)
      return;

    fr->VertexBufferHost = new ImDrawVert[fr->VertexBufferSize];
  }
  if (fr->IndexBuffer == nullptr || fr->IndexBufferSize < draw_data->TotalIdxCount)
  {
    if (fr->IndexBuffer)
    {
      wgpuBufferDestroy(fr->IndexBuffer);
      wgpuBufferRelease(fr->IndexBuffer);
    }
    SafeRelease(fr->IndexBufferHost);
    fr->IndexBufferSize = draw_data->TotalIdxCount + 10000;

    WGPUBufferDescriptor ib_desc =
        {
            nullptr,
            "Dear ImGui Index buffer",
            WGPUBufferUsage_CopyDst | WGPUBufferUsage_Index,
            fr->IndexBufferSize * sizeof(ImDrawIdx),
            false
        };
    fr->IndexBuffer = wgpuDeviceCreateBuffer(g_wgpuDevice, &ib_desc);
    if (!fr->IndexBuffer)
      return;

    fr->IndexBufferHost = new ImDrawIdx[fr->IndexBufferSize];
  }

  // Upload vertex/index data into a single contiguous GPU buffer
  ImDrawVert* vtx_dst = (ImDrawVert*)fr->VertexBufferHost;
  ImDrawIdx* idx_dst = (ImDrawIdx*)fr->IndexBufferHost;
  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;
  }
  int64_t vb_write_size = ((char*)vtx_dst - (char*)fr->VertexBufferHost + 3) & ~3;
  int64_t ib_write_size = ((char*)idx_dst - (char*)fr->IndexBufferHost  + 3) & ~3;
  wgpuQueueWriteBuffer(g_defaultQueue, fr->VertexBuffer, 0, fr->VertexBufferHost, vb_write_size);
  wgpuQueueWriteBuffer(g_defaultQueue, fr->IndexBuffer,  0, fr->IndexBufferHost,  ib_write_size);

  // Setup desired render state
  ImGui_ImplWGPU_SetupRenderState(draw_data, pass_encoder, fr);

  // Render command lists
  // (Because we merged all buffers into a single one, we maintain our own offset into them)
  int global_vtx_offset = 0;
  int global_idx_offset = 0;
  ImVec2 clip_scale = draw_data->FramebufferScale;
  ImVec2 clip_off = draw_data->DisplayPos;
  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 != nullptr)
      {
        // User callback, registered via ImDrawList::AddCallback()
        // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
        if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
          ImGui_ImplWGPU_SetupRenderState(draw_data, pass_encoder, fr);
        else
          pcmd->UserCallback(cmd_list, pcmd);
      }
      else
      {
        // Bind custom texture
        ImTextureID tex_id = pcmd->GetTexID();
        ImGuiID tex_id_hash = ImHashData(&tex_id, sizeof(tex_id));
        auto bind_group = g_resources.ImageBindGroups.GetVoidPtr(tex_id_hash);
        if (bind_group)
        {
          wgpuRenderPassEncoderSetBindGroup(pass_encoder, 1, (WGPUBindGroup)bind_group, 0, nullptr);
        }
        else
        {
          WGPUBindGroup image_bind_group = ImGui_ImplWGPU_CreateImageBindGroup(g_resources.ImageBindGroupLayout, (WGPUTextureView)tex_id);
          g_resources.ImageBindGroups.SetVoidPtr(tex_id_hash, image_bind_group);
          wgpuRenderPassEncoderSetBindGroup(pass_encoder, 1, image_bind_group, 0, nullptr);
        }

        // Project scissor/clipping rectangles into framebuffer space
        ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
        ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
        if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
          continue;

        // Apply scissor/clipping rectangle, Draw
        wgpuRenderPassEncoderSetScissorRect(pass_encoder, (uint32_t)clip_min.x, (uint32_t)clip_min.y, (uint32_t)(clip_max.x - clip_min.x), (uint32_t)(clip_max.y - clip_min.y));
        wgpuRenderPassEncoderDrawIndexed(pass_encoder, pcmd->ElemCount, 1, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset, 0);
      }
    }
    global_idx_offset += cmd_list->IdxBuffer.Size;
    global_vtx_offset += cmd_list->VtxBuffer.Size;
  }
}

static void ImGui_ImplWGPU_CreateFontsTexture()
{
  // Build texture atlas
  ImGuiIO& io = ImGui::GetIO();
  unsigned char* pixels;
  int width, height, size_pp;
  io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &size_pp);

  // Upload texture to graphics system
  {
    WGPUTextureDescriptor tex_desc = {};
    tex_desc.label = "Dear ImGui Font Texture";
    tex_desc.dimension = WGPUTextureDimension_2D;
    tex_desc.size.width = width;
    tex_desc.size.height = height;
    tex_desc.size.depthOrArrayLayers = 1;
    tex_desc.sampleCount = 1;
    tex_desc.format = WGPUTextureFormat_RGBA8Unorm;
    tex_desc.mipLevelCount = 1;
    tex_desc.usage = WGPUTextureUsage_CopyDst | WGPUTextureUsage_TextureBinding;
    g_resources.FontTexture = wgpuDeviceCreateTexture(g_wgpuDevice, &tex_desc);

    WGPUTextureViewDescriptor tex_view_desc = {};
    tex_view_desc.format = WGPUTextureFormat_RGBA8Unorm;
    tex_view_desc.dimension = WGPUTextureViewDimension_2D;
    tex_view_desc.baseMipLevel = 0;
    tex_view_desc.mipLevelCount = 1;
    tex_view_desc.baseArrayLayer = 0;
    tex_view_desc.arrayLayerCount = 1;
    tex_view_desc.aspect = WGPUTextureAspect_All;
    g_resources.FontTextureView = wgpuTextureCreateView(g_resources.FontTexture, &tex_view_desc);
  }

  // Upload texture data
  {
    WGPUImageCopyTexture dst_view = {};
    dst_view.texture = g_resources.FontTexture;
    dst_view.mipLevel = 0;
    dst_view.origin = { 0, 0, 0 };
    dst_view.aspect = WGPUTextureAspect_All;
    WGPUTextureDataLayout layout = {};
    layout.offset = 0;
    layout.bytesPerRow = width * size_pp;
    layout.rowsPerImage = height;
    WGPUExtent3D size = { (uint32_t)width, (uint32_t)height, 1 };
    wgpuQueueWriteTexture(g_defaultQueue, &dst_view, pixels, (uint32_t)(width * size_pp * height), &layout, &size);
  }

  // Create the associated sampler
  // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
  {
    WGPUSamplerDescriptor sampler_desc = {};
    sampler_desc.minFilter = WGPUFilterMode_Linear;
    sampler_desc.magFilter = WGPUFilterMode_Linear;
    sampler_desc.mipmapFilter = WGPUFilterMode_Linear;
    sampler_desc.addressModeU = WGPUAddressMode_Repeat;
    sampler_desc.addressModeV = WGPUAddressMode_Repeat;
    sampler_desc.addressModeW = WGPUAddressMode_Repeat;
    sampler_desc.maxAnisotropy = 1;
    g_resources.Sampler = wgpuDeviceCreateSampler(g_wgpuDevice, &sampler_desc);
  }

  // Store our identifier
  static_assert(sizeof(ImTextureID) >= sizeof(g_resources.FontTexture), "Can't pack descriptor handle into TexID, 32-bit not supported yet.");
  io.Fonts->SetTexID((ImTextureID)g_resources.FontTextureView);
}

static void ImGui_ImplWGPU_CreateUniformBuffer()
{
  WGPUBufferDescriptor ub_desc =
      {
          nullptr,
          "Dear ImGui Uniform buffer",
          WGPUBufferUsage_CopyDst | WGPUBufferUsage_Uniform,
          sizeof(Uniforms),
          false
      };
  g_resources.Uniforms = wgpuDeviceCreateBuffer(g_wgpuDevice, &ub_desc);
}

bool ImGui_ImplWGPU_CreateDeviceObjects()
{
  if (!g_wgpuDevice)
    return false;
  if (g_pipelineState)
    ImGui_ImplWGPU_InvalidateDeviceObjects();

  // Create render pipeline
  WGPURenderPipelineDescriptor graphics_pipeline_desc = {};
  graphics_pipeline_desc.primitive.topology = WGPUPrimitiveTopology_TriangleList;
  graphics_pipeline_desc.primitive.stripIndexFormat = WGPUIndexFormat_Undefined;
  graphics_pipeline_desc.primitive.frontFace = WGPUFrontFace_CW;
  graphics_pipeline_desc.primitive.cullMode = WGPUCullMode_None;
  graphics_pipeline_desc.multisample.count = 1;
  graphics_pipeline_desc.multisample.mask = UINT_MAX;
  graphics_pipeline_desc.multisample.alphaToCoverageEnabled = false;
  graphics_pipeline_desc.layout = nullptr; // Use automatic layout generation

  // Create the shader module
  WGPUShaderModule shader_module = ImGui_ImplWGPU_CreateShaderModule(__wgsl_shader);
  graphics_pipeline_desc.vertex.module = shader_module;
  graphics_pipeline_desc.vertex.entryPoint = "vs_main";

  // Vertex input configuration
  WGPUVertexAttribute attribute_desc[] =
      {
          { WGPUVertexFormat_Float32x2, (uint64_t)IM_OFFSETOF(ImDrawVert, pos), 0 },
          { WGPUVertexFormat_Float32x2, (uint64_t)IM_OFFSETOF(ImDrawVert, uv),  1 },
          { WGPUVertexFormat_Unorm8x4,  (uint64_t)IM_OFFSETOF(ImDrawVert, col), 2 },
      };

  WGPUVertexBufferLayout buffer_layouts[1];
  buffer_layouts[0].arrayStride = sizeof(ImDrawVert);
  buffer_layouts[0].stepMode = WGPUVertexStepMode_Vertex;
  buffer_layouts[0].attributeCount = 3;
  buffer_layouts[0].attributes = attribute_desc;

  graphics_pipeline_desc.vertex.bufferCount = 1;
  graphics_pipeline_desc.vertex.buffers = buffer_layouts;

  // Create the blending setup
  WGPUBlendState blend_state = {};
  blend_state.alpha.operation = WGPUBlendOperation_Add;
  blend_state.alpha.srcFactor = WGPUBlendFactor_One;
  blend_state.alpha.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha;
  blend_state.color.operation = WGPUBlendOperation_Add;
  blend_state.color.srcFactor = WGPUBlendFactor_SrcAlpha;
  blend_state.color.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha;

  WGPUColorTargetState color_state = {};
  color_state.format = g_renderTargetFormat;
  color_state.blend = &blend_state;
  color_state.writeMask = WGPUColorWriteMask_All;

  WGPUFragmentState fragment_state = {};
  fragment_state.module = shader_module;
  fragment_state.entryPoint = "fs_main";
  fragment_state.targetCount = 1;
  fragment_state.targets = &color_state;

  graphics_pipeline_desc.fragment = &fragment_state;

  // Create depth-stencil State
  WGPUDepthStencilState depth_stencil_state = {};
  depth_stencil_state.format = g_depthStencilFormat;
  depth_stencil_state.depthWriteEnabled = false;
  depth_stencil_state.depthCompare = WGPUCompareFunction_Always;
  depth_stencil_state.stencilFront.compare = WGPUCompareFunction_Always;
  depth_stencil_state.stencilBack.compare = WGPUCompareFunction_Always;

  // Configure disabled depth-stencil state
  graphics_pipeline_desc.depthStencil = g_depthStencilFormat == WGPUTextureFormat_Undefined  ? nullptr :  &depth_stencil_state;

  g_pipelineState = wgpuDeviceCreateRenderPipeline(g_wgpuDevice, &graphics_pipeline_desc);

  ImGui_ImplWGPU_CreateFontsTexture();
  ImGui_ImplWGPU_CreateUniformBuffer();

  // Create resource bind group
  WGPUBindGroupLayout bg_layouts[2];
  bg_layouts[0] = wgpuRenderPipelineGetBindGroupLayout(g_pipelineState, 0);
  bg_layouts[1] = wgpuRenderPipelineGetBindGroupLayout(g_pipelineState, 1);

  WGPUBindGroupEntry common_bg_entries[] =
      {
          { nullptr, 0, g_resources.Uniforms, 0, sizeof(Uniforms), 0, 0 },
          { nullptr, 1, 0, 0, 0, g_resources.Sampler, 0 },
      };

  WGPUBindGroupDescriptor common_bg_descriptor = {};
  common_bg_descriptor.layout = bg_layouts[0];
  common_bg_descriptor.entryCount = sizeof(common_bg_entries) / sizeof(WGPUBindGroupEntry);
  common_bg_descriptor.entries = common_bg_entries;
  g_resources.CommonBindGroup = wgpuDeviceCreateBindGroup(g_wgpuDevice, &common_bg_descriptor);

  WGPUBindGroup image_bind_group = ImGui_ImplWGPU_CreateImageBindGroup(bg_layouts[1], g_resources.FontTextureView);
  g_resources.ImageBindGroup = image_bind_group;
  g_resources.ImageBindGroupLayout = bg_layouts[1];
  g_resources.ImageBindGroups.SetVoidPtr(ImHashData(&g_resources.FontTextureView, sizeof(ImTextureID)), image_bind_group);

  SafeRelease(shader_module);
  SafeRelease(bg_layouts[0]);

  return true;
}

void ImGui_ImplWGPU_InvalidateDeviceObjects()
{
  if (!g_wgpuDevice)
    return;

  SafeRelease(g_pipelineState);
  SafeRelease(g_resources);

  ImGuiIO& io = ImGui::GetIO();
  io.Fonts->SetTexID(nullptr); // We copied g_pFontTextureView to io.Fonts->TexID so let's clear that as well.

  for (unsigned int i = 0; i < g_numFramesInFlight; i++)
    SafeRelease(g_pFrameResources[i]);
}

bool ImGui_ImplWGPU_Init(WGPUDevice device, int num_frames_in_flight, WGPUTextureFormat rt_format, WGPUTextureFormat depth_format)
{
  // Setup backend capabilities flags
  ImGuiIO& io = ImGui::GetIO();
  io.BackendRendererName = "imgui_impl_webgpu";
  io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.

  g_wgpuDevice = device;
  g_defaultQueue = wgpuDeviceGetQueue(g_wgpuDevice);
  g_renderTargetFormat = rt_format;
  g_depthStencilFormat = depth_format;
  g_pFrameResources = new FrameResources[num_frames_in_flight];
  g_numFramesInFlight = num_frames_in_flight;
  g_frameIndex = UINT_MAX;

  g_resources.FontTexture = nullptr;
  g_resources.FontTextureView = nullptr;
  g_resources.Sampler = nullptr;
  g_resources.Uniforms = nullptr;
  g_resources.CommonBindGroup = nullptr;
  g_resources.ImageBindGroups.Data.reserve(100);
  g_resources.ImageBindGroup = nullptr;
  g_resources.ImageBindGroupLayout = nullptr;

  // Create buffers with a default size (they will later be grown as needed)
  for (int i = 0; i < num_frames_in_flight; i++)
  {
    FrameResources* fr = &g_pFrameResources[i];
    fr->IndexBuffer = nullptr;
    fr->VertexBuffer = nullptr;
    fr->IndexBufferHost = nullptr;
    fr->VertexBufferHost = nullptr;
    fr->IndexBufferSize = 10000;
    fr->VertexBufferSize = 5000;
  }

  return true;
}

void ImGui_ImplWGPU_Shutdown()
{
  ImGui_ImplWGPU_InvalidateDeviceObjects();
  delete[] g_pFrameResources;
  g_pFrameResources = nullptr;
  wgpuQueueRelease(g_defaultQueue);
  g_wgpuDevice = nullptr;
  g_numFramesInFlight = 0;
  g_frameIndex = UINT_MAX;
}

void ImGui_ImplWGPU_NewFrame()
{
  if (!g_pipelineState)
    ImGui_ImplWGPU_CreateDeviceObjects();
}