imgui

FORK: Dear ImGui: Bloat-free Graphical User interface for C++ with minimal dependencies
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imgui_impl_dx12.cpp (31184B)


      1 // dear imgui: Renderer Backend for DirectX12
      2 // This needs to be used along with a Platform Backend (e.g. Win32)
      3 
      4 // Implemented features:
      5 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
      6 //  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
      7 
      8 // Important: to compile on 32-bit systems, this backend requires code to be compiled with '#define ImTextureID ImU64'.
      9 // This is because we need ImTextureID to carry a 64-bit value and by default ImTextureID is defined as void*.
     10 // This define is set in the example .vcxproj file and need to be replicated in your app or by adding it to your imconfig.h file.
     11 
     12 // You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
     13 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
     14 // Read online: https://github.com/ocornut/imgui/tree/master/docs
     15 
     16 // CHANGELOG
     17 // (minor and older changes stripped away, please see git history for details)
     18 //  2021-05-19: DirectX12: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
     19 //  2021-02-18: DirectX12: Change blending equation to preserve alpha in output buffer.
     20 //  2021-01-11: DirectX12: Improve Windows 7 compatibility (for D3D12On7) by loading d3d12.dll dynamically.
     21 //  2020-09-16: DirectX12: Avoid rendering calls with zero-sized scissor rectangle since it generates a validation layer warning.
     22 //  2020-09-08: DirectX12: Clarified support for building on 32-bit systems by redefining ImTextureID.
     23 //  2019-10-18: DirectX12: *BREAKING CHANGE* Added extra ID3D12DescriptorHeap parameter to ImGui_ImplDX12_Init() function.
     24 //  2019-05-29: DirectX12: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
     25 //  2019-04-30: DirectX12: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
     26 //  2019-03-29: Misc: Various minor tidying up.
     27 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
     28 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
     29 //  2018-06-12: DirectX12: Moved the ID3D12GraphicsCommandList* parameter from NewFrame() to RenderDrawData().
     30 //  2018-06-08: Misc: Extracted imgui_impl_dx12.cpp/.h away from the old combined DX12+Win32 example.
     31 //  2018-06-08: DirectX12: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle (to ease support for future multi-viewport).
     32 //  2018-02-22: Merged into master with all Win32 code synchronized to other examples.
     33 
     34 #include "imgui.h"
     35 #include "imgui_impl_dx12.h"
     36 
     37 // DirectX
     38 #include <d3d12.h>
     39 #include <dxgi1_4.h>
     40 #include <d3dcompiler.h>
     41 #ifdef _MSC_VER
     42 #pragma comment(lib, "d3dcompiler") // Automatically link with d3dcompiler.lib as we are using D3DCompile() below.
     43 #endif
     44 
     45 // DirectX data
     46 static ID3D12Device*                g_pd3dDevice = NULL;
     47 static ID3D12RootSignature*         g_pRootSignature = NULL;
     48 static ID3D12PipelineState*         g_pPipelineState = NULL;
     49 static DXGI_FORMAT                  g_RTVFormat = DXGI_FORMAT_UNKNOWN;
     50 static ID3D12Resource*              g_pFontTextureResource = NULL;
     51 static D3D12_CPU_DESCRIPTOR_HANDLE  g_hFontSrvCpuDescHandle = {};
     52 static D3D12_GPU_DESCRIPTOR_HANDLE  g_hFontSrvGpuDescHandle = {};
     53 
     54 struct FrameResources
     55 {
     56     ID3D12Resource*     IndexBuffer;
     57     ID3D12Resource*     VertexBuffer;
     58     int                 IndexBufferSize;
     59     int                 VertexBufferSize;
     60 };
     61 static FrameResources*  g_pFrameResources = NULL;
     62 static UINT             g_numFramesInFlight = 0;
     63 static UINT             g_frameIndex = UINT_MAX;
     64 
     65 template<typename T>
     66 static void SafeRelease(T*& res)
     67 {
     68     if (res)
     69         res->Release();
     70     res = NULL;
     71 }
     72 
     73 struct VERTEX_CONSTANT_BUFFER
     74 {
     75     float   mvp[4][4];
     76 };
     77 
     78 static void ImGui_ImplDX12_SetupRenderState(ImDrawData* draw_data, ID3D12GraphicsCommandList* ctx, FrameResources* fr)
     79 {
     80     // Setup orthographic projection matrix into our constant buffer
     81     // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
     82     VERTEX_CONSTANT_BUFFER vertex_constant_buffer;
     83     {
     84         float L = draw_data->DisplayPos.x;
     85         float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
     86         float T = draw_data->DisplayPos.y;
     87         float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
     88         float mvp[4][4] =
     89         {
     90             { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
     91             { 0.0f,         2.0f/(T-B),     0.0f,       0.0f },
     92             { 0.0f,         0.0f,           0.5f,       0.0f },
     93             { (R+L)/(L-R),  (T+B)/(B-T),    0.5f,       1.0f },
     94         };
     95         memcpy(&vertex_constant_buffer.mvp, mvp, sizeof(mvp));
     96     }
     97 
     98     // Setup viewport
     99     D3D12_VIEWPORT vp;
    100     memset(&vp, 0, sizeof(D3D12_VIEWPORT));
    101     vp.Width = draw_data->DisplaySize.x;
    102     vp.Height = draw_data->DisplaySize.y;
    103     vp.MinDepth = 0.0f;
    104     vp.MaxDepth = 1.0f;
    105     vp.TopLeftX = vp.TopLeftY = 0.0f;
    106     ctx->RSSetViewports(1, &vp);
    107 
    108     // Bind shader and vertex buffers
    109     unsigned int stride = sizeof(ImDrawVert);
    110     unsigned int offset = 0;
    111     D3D12_VERTEX_BUFFER_VIEW vbv;
    112     memset(&vbv, 0, sizeof(D3D12_VERTEX_BUFFER_VIEW));
    113     vbv.BufferLocation = fr->VertexBuffer->GetGPUVirtualAddress() + offset;
    114     vbv.SizeInBytes = fr->VertexBufferSize * stride;
    115     vbv.StrideInBytes = stride;
    116     ctx->IASetVertexBuffers(0, 1, &vbv);
    117     D3D12_INDEX_BUFFER_VIEW ibv;
    118     memset(&ibv, 0, sizeof(D3D12_INDEX_BUFFER_VIEW));
    119     ibv.BufferLocation = fr->IndexBuffer->GetGPUVirtualAddress();
    120     ibv.SizeInBytes = fr->IndexBufferSize * sizeof(ImDrawIdx);
    121     ibv.Format = sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT;
    122     ctx->IASetIndexBuffer(&ibv);
    123     ctx->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
    124     ctx->SetPipelineState(g_pPipelineState);
    125     ctx->SetGraphicsRootSignature(g_pRootSignature);
    126     ctx->SetGraphicsRoot32BitConstants(0, 16, &vertex_constant_buffer, 0);
    127 
    128     // Setup blend factor
    129     const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
    130     ctx->OMSetBlendFactor(blend_factor);
    131 }
    132 
    133 // Render function
    134 void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandList* ctx)
    135 {
    136     // Avoid rendering when minimized
    137     if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
    138         return;
    139 
    140     // FIXME: I'm assuming that this only gets called once per frame!
    141     // If not, we can't just re-allocate the IB or VB, we'll have to do a proper allocator.
    142     g_frameIndex = g_frameIndex + 1;
    143     FrameResources* fr = &g_pFrameResources[g_frameIndex % g_numFramesInFlight];
    144 
    145     // Create and grow vertex/index buffers if needed
    146     if (fr->VertexBuffer == NULL || fr->VertexBufferSize < draw_data->TotalVtxCount)
    147     {
    148         SafeRelease(fr->VertexBuffer);
    149         fr->VertexBufferSize = draw_data->TotalVtxCount + 5000;
    150         D3D12_HEAP_PROPERTIES props;
    151         memset(&props, 0, sizeof(D3D12_HEAP_PROPERTIES));
    152         props.Type = D3D12_HEAP_TYPE_UPLOAD;
    153         props.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
    154         props.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
    155         D3D12_RESOURCE_DESC desc;
    156         memset(&desc, 0, sizeof(D3D12_RESOURCE_DESC));
    157         desc.Dimension = D3D12_RESOURCE_DIMENSION_BUFFER;
    158         desc.Width = fr->VertexBufferSize * sizeof(ImDrawVert);
    159         desc.Height = 1;
    160         desc.DepthOrArraySize = 1;
    161         desc.MipLevels = 1;
    162         desc.Format = DXGI_FORMAT_UNKNOWN;
    163         desc.SampleDesc.Count = 1;
    164         desc.Layout = D3D12_TEXTURE_LAYOUT_ROW_MAJOR;
    165         desc.Flags = D3D12_RESOURCE_FLAG_NONE;
    166         if (g_pd3dDevice->CreateCommittedResource(&props, D3D12_HEAP_FLAG_NONE, &desc, D3D12_RESOURCE_STATE_GENERIC_READ, NULL, IID_PPV_ARGS(&fr->VertexBuffer)) < 0)
    167             return;
    168     }
    169     if (fr->IndexBuffer == NULL || fr->IndexBufferSize < draw_data->TotalIdxCount)
    170     {
    171         SafeRelease(fr->IndexBuffer);
    172         fr->IndexBufferSize = draw_data->TotalIdxCount + 10000;
    173         D3D12_HEAP_PROPERTIES props;
    174         memset(&props, 0, sizeof(D3D12_HEAP_PROPERTIES));
    175         props.Type = D3D12_HEAP_TYPE_UPLOAD;
    176         props.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
    177         props.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
    178         D3D12_RESOURCE_DESC desc;
    179         memset(&desc, 0, sizeof(D3D12_RESOURCE_DESC));
    180         desc.Dimension = D3D12_RESOURCE_DIMENSION_BUFFER;
    181         desc.Width = fr->IndexBufferSize * sizeof(ImDrawIdx);
    182         desc.Height = 1;
    183         desc.DepthOrArraySize = 1;
    184         desc.MipLevels = 1;
    185         desc.Format = DXGI_FORMAT_UNKNOWN;
    186         desc.SampleDesc.Count = 1;
    187         desc.Layout = D3D12_TEXTURE_LAYOUT_ROW_MAJOR;
    188         desc.Flags = D3D12_RESOURCE_FLAG_NONE;
    189         if (g_pd3dDevice->CreateCommittedResource(&props, D3D12_HEAP_FLAG_NONE, &desc, D3D12_RESOURCE_STATE_GENERIC_READ, NULL, IID_PPV_ARGS(&fr->IndexBuffer)) < 0)
    190             return;
    191     }
    192 
    193     // Upload vertex/index data into a single contiguous GPU buffer
    194     void* vtx_resource, *idx_resource;
    195     D3D12_RANGE range;
    196     memset(&range, 0, sizeof(D3D12_RANGE));
    197     if (fr->VertexBuffer->Map(0, &range, &vtx_resource) != S_OK)
    198         return;
    199     if (fr->IndexBuffer->Map(0, &range, &idx_resource) != S_OK)
    200         return;
    201     ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource;
    202     ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource;
    203     for (int n = 0; n < draw_data->CmdListsCount; n++)
    204     {
    205         const ImDrawList* cmd_list = draw_data->CmdLists[n];
    206         memcpy(vtx_dst, cmd_list->VtxBuffer.Data, cmd_list->VtxBuffer.Size * sizeof(ImDrawVert));
    207         memcpy(idx_dst, cmd_list->IdxBuffer.Data, cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx));
    208         vtx_dst += cmd_list->VtxBuffer.Size;
    209         idx_dst += cmd_list->IdxBuffer.Size;
    210     }
    211     fr->VertexBuffer->Unmap(0, &range);
    212     fr->IndexBuffer->Unmap(0, &range);
    213 
    214     // Setup desired DX state
    215     ImGui_ImplDX12_SetupRenderState(draw_data, ctx, fr);
    216 
    217     // Render command lists
    218     // (Because we merged all buffers into a single one, we maintain our own offset into them)
    219     int global_vtx_offset = 0;
    220     int global_idx_offset = 0;
    221     ImVec2 clip_off = draw_data->DisplayPos;
    222     for (int n = 0; n < draw_data->CmdListsCount; n++)
    223     {
    224         const ImDrawList* cmd_list = draw_data->CmdLists[n];
    225         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
    226         {
    227             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
    228             if (pcmd->UserCallback != NULL)
    229             {
    230                 // User callback, registered via ImDrawList::AddCallback()
    231                 // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
    232                 if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
    233                     ImGui_ImplDX12_SetupRenderState(draw_data, ctx, fr);
    234                 else
    235                     pcmd->UserCallback(cmd_list, pcmd);
    236             }
    237             else
    238             {
    239                 // Apply Scissor, Bind texture, Draw
    240                 const D3D12_RECT r = { (LONG)(pcmd->ClipRect.x - clip_off.x), (LONG)(pcmd->ClipRect.y - clip_off.y), (LONG)(pcmd->ClipRect.z - clip_off.x), (LONG)(pcmd->ClipRect.w - clip_off.y) };
    241                 if (r.right > r.left && r.bottom > r.top)
    242                 {
    243                     D3D12_GPU_DESCRIPTOR_HANDLE texture_handle = {};
    244                     texture_handle.ptr = (UINT64)(intptr_t)pcmd->GetTexID();
    245                     ctx->SetGraphicsRootDescriptorTable(1, texture_handle);
    246                     ctx->RSSetScissorRects(1, &r);
    247                     ctx->DrawIndexedInstanced(pcmd->ElemCount, 1, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset, 0);
    248                 }
    249             }
    250         }
    251         global_idx_offset += cmd_list->IdxBuffer.Size;
    252         global_vtx_offset += cmd_list->VtxBuffer.Size;
    253     }
    254 }
    255 
    256 static void ImGui_ImplDX12_CreateFontsTexture()
    257 {
    258     // Build texture atlas
    259     ImGuiIO& io = ImGui::GetIO();
    260     unsigned char* pixels;
    261     int width, height;
    262     io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
    263 
    264     // Upload texture to graphics system
    265     {
    266         D3D12_HEAP_PROPERTIES props;
    267         memset(&props, 0, sizeof(D3D12_HEAP_PROPERTIES));
    268         props.Type = D3D12_HEAP_TYPE_DEFAULT;
    269         props.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
    270         props.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
    271 
    272         D3D12_RESOURCE_DESC desc;
    273         ZeroMemory(&desc, sizeof(desc));
    274         desc.Dimension = D3D12_RESOURCE_DIMENSION_TEXTURE2D;
    275         desc.Alignment = 0;
    276         desc.Width = width;
    277         desc.Height = height;
    278         desc.DepthOrArraySize = 1;
    279         desc.MipLevels = 1;
    280         desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    281         desc.SampleDesc.Count = 1;
    282         desc.SampleDesc.Quality = 0;
    283         desc.Layout = D3D12_TEXTURE_LAYOUT_UNKNOWN;
    284         desc.Flags = D3D12_RESOURCE_FLAG_NONE;
    285 
    286         ID3D12Resource* pTexture = NULL;
    287         g_pd3dDevice->CreateCommittedResource(&props, D3D12_HEAP_FLAG_NONE, &desc,
    288             D3D12_RESOURCE_STATE_COPY_DEST, NULL, IID_PPV_ARGS(&pTexture));
    289 
    290         UINT uploadPitch = (width * 4 + D3D12_TEXTURE_DATA_PITCH_ALIGNMENT - 1u) & ~(D3D12_TEXTURE_DATA_PITCH_ALIGNMENT - 1u);
    291         UINT uploadSize = height * uploadPitch;
    292         desc.Dimension = D3D12_RESOURCE_DIMENSION_BUFFER;
    293         desc.Alignment = 0;
    294         desc.Width = uploadSize;
    295         desc.Height = 1;
    296         desc.DepthOrArraySize = 1;
    297         desc.MipLevels = 1;
    298         desc.Format = DXGI_FORMAT_UNKNOWN;
    299         desc.SampleDesc.Count = 1;
    300         desc.SampleDesc.Quality = 0;
    301         desc.Layout = D3D12_TEXTURE_LAYOUT_ROW_MAJOR;
    302         desc.Flags = D3D12_RESOURCE_FLAG_NONE;
    303 
    304         props.Type = D3D12_HEAP_TYPE_UPLOAD;
    305         props.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
    306         props.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
    307 
    308         ID3D12Resource* uploadBuffer = NULL;
    309         HRESULT hr = g_pd3dDevice->CreateCommittedResource(&props, D3D12_HEAP_FLAG_NONE, &desc,
    310             D3D12_RESOURCE_STATE_GENERIC_READ, NULL, IID_PPV_ARGS(&uploadBuffer));
    311         IM_ASSERT(SUCCEEDED(hr));
    312 
    313         void* mapped = NULL;
    314         D3D12_RANGE range = { 0, uploadSize };
    315         hr = uploadBuffer->Map(0, &range, &mapped);
    316         IM_ASSERT(SUCCEEDED(hr));
    317         for (int y = 0; y < height; y++)
    318             memcpy((void*) ((uintptr_t) mapped + y * uploadPitch), pixels + y * width * 4, width * 4);
    319         uploadBuffer->Unmap(0, &range);
    320 
    321         D3D12_TEXTURE_COPY_LOCATION srcLocation = {};
    322         srcLocation.pResource = uploadBuffer;
    323         srcLocation.Type = D3D12_TEXTURE_COPY_TYPE_PLACED_FOOTPRINT;
    324         srcLocation.PlacedFootprint.Footprint.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    325         srcLocation.PlacedFootprint.Footprint.Width = width;
    326         srcLocation.PlacedFootprint.Footprint.Height = height;
    327         srcLocation.PlacedFootprint.Footprint.Depth = 1;
    328         srcLocation.PlacedFootprint.Footprint.RowPitch = uploadPitch;
    329 
    330         D3D12_TEXTURE_COPY_LOCATION dstLocation = {};
    331         dstLocation.pResource = pTexture;
    332         dstLocation.Type = D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX;
    333         dstLocation.SubresourceIndex = 0;
    334 
    335         D3D12_RESOURCE_BARRIER barrier = {};
    336         barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
    337         barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
    338         barrier.Transition.pResource   = pTexture;
    339         barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
    340         barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_COPY_DEST;
    341         barrier.Transition.StateAfter  = D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE;
    342 
    343         ID3D12Fence* fence = NULL;
    344         hr = g_pd3dDevice->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&fence));
    345         IM_ASSERT(SUCCEEDED(hr));
    346 
    347         HANDLE event = CreateEvent(0, 0, 0, 0);
    348         IM_ASSERT(event != NULL);
    349 
    350         D3D12_COMMAND_QUEUE_DESC queueDesc = {};
    351         queueDesc.Type     = D3D12_COMMAND_LIST_TYPE_DIRECT;
    352         queueDesc.Flags    = D3D12_COMMAND_QUEUE_FLAG_NONE;
    353         queueDesc.NodeMask = 1;
    354 
    355         ID3D12CommandQueue* cmdQueue = NULL;
    356         hr = g_pd3dDevice->CreateCommandQueue(&queueDesc, IID_PPV_ARGS(&cmdQueue));
    357         IM_ASSERT(SUCCEEDED(hr));
    358 
    359         ID3D12CommandAllocator* cmdAlloc = NULL;
    360         hr = g_pd3dDevice->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&cmdAlloc));
    361         IM_ASSERT(SUCCEEDED(hr));
    362 
    363         ID3D12GraphicsCommandList* cmdList = NULL;
    364         hr = g_pd3dDevice->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, cmdAlloc, NULL, IID_PPV_ARGS(&cmdList));
    365         IM_ASSERT(SUCCEEDED(hr));
    366 
    367         cmdList->CopyTextureRegion(&dstLocation, 0, 0, 0, &srcLocation, NULL);
    368         cmdList->ResourceBarrier(1, &barrier);
    369 
    370         hr = cmdList->Close();
    371         IM_ASSERT(SUCCEEDED(hr));
    372 
    373         cmdQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&cmdList);
    374         hr = cmdQueue->Signal(fence, 1);
    375         IM_ASSERT(SUCCEEDED(hr));
    376 
    377         fence->SetEventOnCompletion(1, event);
    378         WaitForSingleObject(event, INFINITE);
    379 
    380         cmdList->Release();
    381         cmdAlloc->Release();
    382         cmdQueue->Release();
    383         CloseHandle(event);
    384         fence->Release();
    385         uploadBuffer->Release();
    386 
    387         // Create texture view
    388         D3D12_SHADER_RESOURCE_VIEW_DESC srvDesc;
    389         ZeroMemory(&srvDesc, sizeof(srvDesc));
    390         srvDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    391         srvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2D;
    392         srvDesc.Texture2D.MipLevels = desc.MipLevels;
    393         srvDesc.Texture2D.MostDetailedMip = 0;
    394         srvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;
    395         g_pd3dDevice->CreateShaderResourceView(pTexture, &srvDesc, g_hFontSrvCpuDescHandle);
    396         SafeRelease(g_pFontTextureResource);
    397         g_pFontTextureResource = pTexture;
    398     }
    399 
    400     // Store our identifier
    401     static_assert(sizeof(ImTextureID) >= sizeof(g_hFontSrvGpuDescHandle.ptr), "Can't pack descriptor handle into TexID, 32-bit not supported yet.");
    402     io.Fonts->SetTexID((ImTextureID)g_hFontSrvGpuDescHandle.ptr);
    403 }
    404 
    405 bool    ImGui_ImplDX12_CreateDeviceObjects()
    406 {
    407     if (!g_pd3dDevice)
    408         return false;
    409     if (g_pPipelineState)
    410         ImGui_ImplDX12_InvalidateDeviceObjects();
    411 
    412     // Create the root signature
    413     {
    414         D3D12_DESCRIPTOR_RANGE descRange = {};
    415         descRange.RangeType = D3D12_DESCRIPTOR_RANGE_TYPE_SRV;
    416         descRange.NumDescriptors = 1;
    417         descRange.BaseShaderRegister = 0;
    418         descRange.RegisterSpace = 0;
    419         descRange.OffsetInDescriptorsFromTableStart = 0;
    420 
    421         D3D12_ROOT_PARAMETER param[2] = {};
    422 
    423         param[0].ParameterType = D3D12_ROOT_PARAMETER_TYPE_32BIT_CONSTANTS;
    424         param[0].Constants.ShaderRegister = 0;
    425         param[0].Constants.RegisterSpace = 0;
    426         param[0].Constants.Num32BitValues = 16;
    427         param[0].ShaderVisibility = D3D12_SHADER_VISIBILITY_VERTEX;
    428 
    429         param[1].ParameterType = D3D12_ROOT_PARAMETER_TYPE_DESCRIPTOR_TABLE;
    430         param[1].DescriptorTable.NumDescriptorRanges = 1;
    431         param[1].DescriptorTable.pDescriptorRanges = &descRange;
    432         param[1].ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
    433 
    434         D3D12_STATIC_SAMPLER_DESC staticSampler = {};
    435         staticSampler.Filter = D3D12_FILTER_MIN_MAG_MIP_LINEAR;
    436         staticSampler.AddressU = D3D12_TEXTURE_ADDRESS_MODE_WRAP;
    437         staticSampler.AddressV = D3D12_TEXTURE_ADDRESS_MODE_WRAP;
    438         staticSampler.AddressW = D3D12_TEXTURE_ADDRESS_MODE_WRAP;
    439         staticSampler.MipLODBias = 0.f;
    440         staticSampler.MaxAnisotropy = 0;
    441         staticSampler.ComparisonFunc = D3D12_COMPARISON_FUNC_ALWAYS;
    442         staticSampler.BorderColor = D3D12_STATIC_BORDER_COLOR_TRANSPARENT_BLACK;
    443         staticSampler.MinLOD = 0.f;
    444         staticSampler.MaxLOD = 0.f;
    445         staticSampler.ShaderRegister = 0;
    446         staticSampler.RegisterSpace = 0;
    447         staticSampler.ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
    448 
    449         D3D12_ROOT_SIGNATURE_DESC desc = {};
    450         desc.NumParameters = _countof(param);
    451         desc.pParameters = param;
    452         desc.NumStaticSamplers = 1;
    453         desc.pStaticSamplers = &staticSampler;
    454         desc.Flags =
    455             D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT |
    456             D3D12_ROOT_SIGNATURE_FLAG_DENY_HULL_SHADER_ROOT_ACCESS |
    457             D3D12_ROOT_SIGNATURE_FLAG_DENY_DOMAIN_SHADER_ROOT_ACCESS |
    458             D3D12_ROOT_SIGNATURE_FLAG_DENY_GEOMETRY_SHADER_ROOT_ACCESS;
    459 
    460         // Load d3d12.dll and D3D12SerializeRootSignature() function address dynamically to facilitate using with D3D12On7.
    461         // See if any version of d3d12.dll is already loaded in the process. If so, give preference to that.
    462         static HINSTANCE d3d12_dll = ::GetModuleHandleA("d3d12.dll");
    463         if (d3d12_dll == NULL)
    464         {
    465             // Attempt to load d3d12.dll from local directories. This will only succeed if
    466             // (1) the current OS is Windows 7, and
    467             // (2) there exists a version of d3d12.dll for Windows 7 (D3D12On7) in one of the following directories.
    468             // See https://github.com/ocornut/imgui/pull/3696 for details.
    469             const char* localD3d12Paths[] = { ".\\d3d12.dll", ".\\d3d12on7\\d3d12.dll", ".\\12on7\\d3d12.dll" }; // A. current directory, B. used by some games, C. used in Microsoft D3D12On7 sample
    470             for (int i = 0; i < IM_ARRAYSIZE(localD3d12Paths); i++)
    471                 if ((d3d12_dll = ::LoadLibraryA(localD3d12Paths[i])) != NULL)
    472                     break;
    473 
    474             // If failed, we are on Windows >= 10.
    475             if (d3d12_dll == NULL)
    476                 d3d12_dll = ::LoadLibraryA("d3d12.dll");
    477 
    478             if (d3d12_dll == NULL)
    479                 return false;
    480         }
    481 
    482         PFN_D3D12_SERIALIZE_ROOT_SIGNATURE D3D12SerializeRootSignatureFn = (PFN_D3D12_SERIALIZE_ROOT_SIGNATURE)::GetProcAddress(d3d12_dll, "D3D12SerializeRootSignature");
    483         if (D3D12SerializeRootSignatureFn == NULL)
    484             return false;
    485 
    486         ID3DBlob* blob = NULL;
    487         if (D3D12SerializeRootSignatureFn(&desc, D3D_ROOT_SIGNATURE_VERSION_1, &blob, NULL) != S_OK)
    488             return false;
    489 
    490         g_pd3dDevice->CreateRootSignature(0, blob->GetBufferPointer(), blob->GetBufferSize(), IID_PPV_ARGS(&g_pRootSignature));
    491         blob->Release();
    492     }
    493 
    494     // By using D3DCompile() from <d3dcompiler.h> / d3dcompiler.lib, we introduce a dependency to a given version of d3dcompiler_XX.dll (see D3DCOMPILER_DLL_A)
    495     // If you would like to use this DX12 sample code but remove this dependency you can:
    496     //  1) compile once, save the compiled shader blobs into a file or source code and pass them to CreateVertexShader()/CreatePixelShader() [preferred solution]
    497     //  2) use code to detect any version of the DLL and grab a pointer to D3DCompile from the DLL.
    498     // See https://github.com/ocornut/imgui/pull/638 for sources and details.
    499 
    500     D3D12_GRAPHICS_PIPELINE_STATE_DESC psoDesc;
    501     memset(&psoDesc, 0, sizeof(D3D12_GRAPHICS_PIPELINE_STATE_DESC));
    502     psoDesc.NodeMask = 1;
    503     psoDesc.PrimitiveTopologyType = D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE;
    504     psoDesc.pRootSignature = g_pRootSignature;
    505     psoDesc.SampleMask = UINT_MAX;
    506     psoDesc.NumRenderTargets = 1;
    507     psoDesc.RTVFormats[0] = g_RTVFormat;
    508     psoDesc.SampleDesc.Count = 1;
    509     psoDesc.Flags = D3D12_PIPELINE_STATE_FLAG_NONE;
    510 
    511     ID3DBlob* vertexShaderBlob;
    512     ID3DBlob* pixelShaderBlob;
    513 
    514     // Create the vertex shader
    515     {
    516         static const char* vertexShader =
    517             "cbuffer vertexBuffer : register(b0) \
    518             {\
    519               float4x4 ProjectionMatrix; \
    520             };\
    521             struct VS_INPUT\
    522             {\
    523               float2 pos : POSITION;\
    524               float4 col : COLOR0;\
    525               float2 uv  : TEXCOORD0;\
    526             };\
    527             \
    528             struct PS_INPUT\
    529             {\
    530               float4 pos : SV_POSITION;\
    531               float4 col : COLOR0;\
    532               float2 uv  : TEXCOORD0;\
    533             };\
    534             \
    535             PS_INPUT main(VS_INPUT input)\
    536             {\
    537               PS_INPUT output;\
    538               output.pos = mul( ProjectionMatrix, float4(input.pos.xy, 0.f, 1.f));\
    539               output.col = input.col;\
    540               output.uv  = input.uv;\
    541               return output;\
    542             }";
    543 
    544         if (FAILED(D3DCompile(vertexShader, strlen(vertexShader), NULL, NULL, NULL, "main", "vs_5_0", 0, 0, &vertexShaderBlob, NULL)))
    545             return false; // NB: Pass ID3D10Blob* pErrorBlob to D3DCompile() to get error showing in (const char*)pErrorBlob->GetBufferPointer(). Make sure to Release() the blob!
    546         psoDesc.VS = { vertexShaderBlob->GetBufferPointer(), vertexShaderBlob->GetBufferSize() };
    547 
    548         // Create the input layout
    549         static D3D12_INPUT_ELEMENT_DESC local_layout[] =
    550         {
    551             { "POSITION", 0, DXGI_FORMAT_R32G32_FLOAT,   0, (UINT)IM_OFFSETOF(ImDrawVert, pos), D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
    552             { "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT,   0, (UINT)IM_OFFSETOF(ImDrawVert, uv),  D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
    553             { "COLOR",    0, DXGI_FORMAT_R8G8B8A8_UNORM, 0, (UINT)IM_OFFSETOF(ImDrawVert, col), D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
    554         };
    555         psoDesc.InputLayout = { local_layout, 3 };
    556     }
    557 
    558     // Create the pixel shader
    559     {
    560         static const char* pixelShader =
    561             "struct PS_INPUT\
    562             {\
    563               float4 pos : SV_POSITION;\
    564               float4 col : COLOR0;\
    565               float2 uv  : TEXCOORD0;\
    566             };\
    567             SamplerState sampler0 : register(s0);\
    568             Texture2D texture0 : register(t0);\
    569             \
    570             float4 main(PS_INPUT input) : SV_Target\
    571             {\
    572               float4 out_col = input.col * texture0.Sample(sampler0, input.uv); \
    573               return out_col; \
    574             }";
    575 
    576         if (FAILED(D3DCompile(pixelShader, strlen(pixelShader), NULL, NULL, NULL, "main", "ps_5_0", 0, 0, &pixelShaderBlob, NULL)))
    577         {
    578             vertexShaderBlob->Release();
    579             return false; // NB: Pass ID3D10Blob* pErrorBlob to D3DCompile() to get error showing in (const char*)pErrorBlob->GetBufferPointer(). Make sure to Release() the blob!
    580         }
    581         psoDesc.PS = { pixelShaderBlob->GetBufferPointer(), pixelShaderBlob->GetBufferSize() };
    582     }
    583 
    584     // Create the blending setup
    585     {
    586         D3D12_BLEND_DESC& desc = psoDesc.BlendState;
    587         desc.AlphaToCoverageEnable = false;
    588         desc.RenderTarget[0].BlendEnable = true;
    589         desc.RenderTarget[0].SrcBlend = D3D12_BLEND_SRC_ALPHA;
    590         desc.RenderTarget[0].DestBlend = D3D12_BLEND_INV_SRC_ALPHA;
    591         desc.RenderTarget[0].BlendOp = D3D12_BLEND_OP_ADD;
    592         desc.RenderTarget[0].SrcBlendAlpha = D3D12_BLEND_ONE;
    593         desc.RenderTarget[0].DestBlendAlpha = D3D12_BLEND_INV_SRC_ALPHA;
    594         desc.RenderTarget[0].BlendOpAlpha = D3D12_BLEND_OP_ADD;
    595         desc.RenderTarget[0].RenderTargetWriteMask = D3D12_COLOR_WRITE_ENABLE_ALL;
    596     }
    597 
    598     // Create the rasterizer state
    599     {
    600         D3D12_RASTERIZER_DESC& desc = psoDesc.RasterizerState;
    601         desc.FillMode = D3D12_FILL_MODE_SOLID;
    602         desc.CullMode = D3D12_CULL_MODE_NONE;
    603         desc.FrontCounterClockwise = FALSE;
    604         desc.DepthBias = D3D12_DEFAULT_DEPTH_BIAS;
    605         desc.DepthBiasClamp = D3D12_DEFAULT_DEPTH_BIAS_CLAMP;
    606         desc.SlopeScaledDepthBias = D3D12_DEFAULT_SLOPE_SCALED_DEPTH_BIAS;
    607         desc.DepthClipEnable = true;
    608         desc.MultisampleEnable = FALSE;
    609         desc.AntialiasedLineEnable = FALSE;
    610         desc.ForcedSampleCount = 0;
    611         desc.ConservativeRaster = D3D12_CONSERVATIVE_RASTERIZATION_MODE_OFF;
    612     }
    613 
    614     // Create depth-stencil State
    615     {
    616         D3D12_DEPTH_STENCIL_DESC& desc = psoDesc.DepthStencilState;
    617         desc.DepthEnable = false;
    618         desc.DepthWriteMask = D3D12_DEPTH_WRITE_MASK_ALL;
    619         desc.DepthFunc = D3D12_COMPARISON_FUNC_ALWAYS;
    620         desc.StencilEnable = false;
    621         desc.FrontFace.StencilFailOp = desc.FrontFace.StencilDepthFailOp = desc.FrontFace.StencilPassOp = D3D12_STENCIL_OP_KEEP;
    622         desc.FrontFace.StencilFunc = D3D12_COMPARISON_FUNC_ALWAYS;
    623         desc.BackFace = desc.FrontFace;
    624     }
    625 
    626     HRESULT result_pipeline_state = g_pd3dDevice->CreateGraphicsPipelineState(&psoDesc, IID_PPV_ARGS(&g_pPipelineState));
    627     vertexShaderBlob->Release();
    628     pixelShaderBlob->Release();
    629     if (result_pipeline_state != S_OK)
    630         return false;
    631 
    632     ImGui_ImplDX12_CreateFontsTexture();
    633 
    634     return true;
    635 }
    636 
    637 void    ImGui_ImplDX12_InvalidateDeviceObjects()
    638 {
    639     if (!g_pd3dDevice)
    640         return;
    641 
    642     SafeRelease(g_pRootSignature);
    643     SafeRelease(g_pPipelineState);
    644     SafeRelease(g_pFontTextureResource);
    645 
    646     ImGuiIO& io = ImGui::GetIO();
    647     io.Fonts->SetTexID(NULL); // We copied g_pFontTextureView to io.Fonts->TexID so let's clear that as well.
    648 
    649     for (UINT i = 0; i < g_numFramesInFlight; i++)
    650     {
    651         FrameResources* fr = &g_pFrameResources[i];
    652         SafeRelease(fr->IndexBuffer);
    653         SafeRelease(fr->VertexBuffer);
    654     }
    655 }
    656 
    657 bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FORMAT rtv_format, ID3D12DescriptorHeap* cbv_srv_heap,
    658                          D3D12_CPU_DESCRIPTOR_HANDLE font_srv_cpu_desc_handle, D3D12_GPU_DESCRIPTOR_HANDLE font_srv_gpu_desc_handle)
    659 {
    660     // Setup backend capabilities flags
    661     ImGuiIO& io = ImGui::GetIO();
    662     io.BackendRendererName = "imgui_impl_dx12";
    663     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
    664 
    665     g_pd3dDevice = device;
    666     g_RTVFormat = rtv_format;
    667     g_hFontSrvCpuDescHandle = font_srv_cpu_desc_handle;
    668     g_hFontSrvGpuDescHandle = font_srv_gpu_desc_handle;
    669     g_pFrameResources = new FrameResources[num_frames_in_flight];
    670     g_numFramesInFlight = num_frames_in_flight;
    671     g_frameIndex = UINT_MAX;
    672     IM_UNUSED(cbv_srv_heap); // Unused in master branch (will be used by multi-viewports)
    673 
    674     // Create buffers with a default size (they will later be grown as needed)
    675     for (int i = 0; i < num_frames_in_flight; i++)
    676     {
    677         FrameResources* fr = &g_pFrameResources[i];
    678         fr->IndexBuffer = NULL;
    679         fr->VertexBuffer = NULL;
    680         fr->IndexBufferSize = 10000;
    681         fr->VertexBufferSize = 5000;
    682     }
    683 
    684     return true;
    685 }
    686 
    687 void ImGui_ImplDX12_Shutdown()
    688 {
    689     ImGui_ImplDX12_InvalidateDeviceObjects();
    690     delete[] g_pFrameResources;
    691     g_pFrameResources = NULL;
    692     g_pd3dDevice = NULL;
    693     g_hFontSrvCpuDescHandle.ptr = 0;
    694     g_hFontSrvGpuDescHandle.ptr = 0;
    695     g_numFramesInFlight = 0;
    696     g_frameIndex = UINT_MAX;
    697 }
    698 
    699 void ImGui_ImplDX12_NewFrame()
    700 {
    701     if (!g_pPipelineState)
    702         ImGui_ImplDX12_CreateDeviceObjects();
    703 }