backends/imgui_impl_dx9.cpp - external/github.com/ocornut/imgui - Git at Google

 // dear imgui: Renderer Backend for DirectX9
 // This needs to be used along with a Platform Backend (e.g. Win32)

 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' 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)
 //  2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
 //  2021-06-25: DirectX9: Explicitly disable texture state stages after >= 1.
 //  2021-05-19: DirectX9: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
 //  2021-04-23: DirectX9: Explicitly setting up more graphics states to increase compatibility with unusual non-default states.
 //  2021-03-18: DirectX9: Calling IDirect3DStateBlock9::Capture() after CreateStateBlock() as a workaround for state restoring issues (see #3857).
 //  2021-03-03: DirectX9: Added support for IMGUI_USE_BGRA_PACKED_COLOR in user's imconfig file.
 //  2021-02-18: DirectX9: Change blending equation to preserve alpha in output buffer.
 //  2019-05-29: DirectX9: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
 //  2019-04-30: DirectX9: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-03-29: Misc: Fixed erroneous assert in ImGui_ImplDX9_InvalidateDeviceObjects().
 //  2019-01-16: Misc: Disabled fog before drawing UI's. Fixes issue #2288.
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
 //  2018-06-08: Misc: Extracted imgui_impl_dx9.cpp/.h away from the old combined DX9+Win32 example.
 //  2018-06-08: DirectX9: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle.
 //  2018-05-07: Render: Saving/restoring Transform because they don't seem to be included in the StateBlock. Setting shading mode to Gouraud.
 //  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplDX9_RenderDrawData() in the .h file so you can call it yourself.
 //  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.

 #include "imgui.h"
 #include "imgui_impl_dx9.h"

 // DirectX
 #include <d3d9.h>

 // DirectX data
 struct ImGui_ImplDX9_Data
 {
     LPDIRECT3DDEVICE9           pd3dDevice;
     LPDIRECT3DVERTEXBUFFER9     pVB;
     LPDIRECT3DINDEXBUFFER9      pIB;
     LPDIRECT3DTEXTURE9          FontTexture;
     int                         VertexBufferSize;
     int                         IndexBufferSize;

     ImGui_ImplDX9_Data()        { memset(this, 0, sizeof(*this)); VertexBufferSize = 5000; IndexBufferSize = 10000; }
 };

 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
 // It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
 static ImGui_ImplDX9_Data*      ImGui_ImplDX9_CreateBackendData()   { return IM_NEW(ImGui_ImplDX9_Data)(); }
 static ImGui_ImplDX9_Data*      ImGui_ImplDX9_GetBackendData()      { return (ImGui_ImplDX9_Data*)ImGui::GetIO().BackendRendererUserData; }
 static void                     ImGui_ImplDX9_DestroyBackendData()  { IM_DELETE(ImGui_ImplDX9_GetBackendData()); }

 struct CUSTOMVERTEX
 {
     float    pos[3];
     D3DCOLOR col;
     float    uv[2];
 };
 #define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE|D3DFVF_TEX1)

 #ifdef IMGUI_USE_BGRA_PACKED_COLOR
 #define IMGUI_COL_TO_DX9_ARGB(_COL)     (_COL)
 #else
 #define IMGUI_COL_TO_DX9_ARGB(_COL)     (((_COL) & 0xFF00FF00) | (((_COL) & 0xFF0000) >> 16) | (((_COL) & 0xFF) << 16))
 #endif

 // Functions
 static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
 {
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();

     // Setup viewport
     D3DVIEWPORT9 vp;
     vp.X = vp.Y = 0;
     vp.Width = (DWORD)draw_data->DisplaySize.x;
     vp.Height = (DWORD)draw_data->DisplaySize.y;
     vp.MinZ = 0.0f;
     vp.MaxZ = 1.0f;
     bd->pd3dDevice->SetViewport(&vp);

     // Setup render state: fixed-pipeline, alpha-blending, no face culling, no depth testing, shade mode (for gradient)
     bd->pd3dDevice->SetPixelShader(NULL);
     bd->pd3dDevice->SetVertexShader(NULL);
     bd->pd3dDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_SOLID);
     bd->pd3dDevice->SetRenderState(D3DRS_SHADEMODE, D3DSHADE_GOURAUD);
     bd->pd3dDevice->SetRenderState(D3DRS_ZWRITEENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_ALPHATESTENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
     bd->pd3dDevice->SetRenderState(D3DRS_ZENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
     bd->pd3dDevice->SetRenderState(D3DRS_BLENDOP, D3DBLENDOP_ADD);
     bd->pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
     bd->pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
     bd->pd3dDevice->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);
     bd->pd3dDevice->SetRenderState(D3DRS_SRCBLENDALPHA, D3DBLEND_ONE);
     bd->pd3dDevice->SetRenderState(D3DRS_DESTBLENDALPHA, D3DBLEND_INVSRCALPHA);
     bd->pd3dDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, TRUE);
     bd->pd3dDevice->SetRenderState(D3DRS_FOGENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_RANGEFOGENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_SPECULARENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_STENCILENABLE, FALSE);
     bd->pd3dDevice->SetRenderState(D3DRS_CLIPPING, TRUE);
     bd->pd3dDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
     bd->pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);
     bd->pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
     bd->pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);
     bd->pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
     bd->pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
     bd->pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE);
     bd->pd3dDevice->SetTextureStageState(1, D3DTSS_COLOROP, D3DTOP_DISABLE);
     bd->pd3dDevice->SetTextureStageState(1, D3DTSS_ALPHAOP, D3DTOP_DISABLE);
     bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
     bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);

     // Setup orthographic projection matrix
     // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
     // Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
     {
         float L = draw_data->DisplayPos.x + 0.5f;
         float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x + 0.5f;
         float T = draw_data->DisplayPos.y + 0.5f;
         float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y + 0.5f;
         D3DMATRIX mat_identity = { { { 1.0f, 0.0f, 0.0f, 0.0f,  0.0f, 1.0f, 0.0f, 0.0f,  0.0f, 0.0f, 1.0f, 0.0f,  0.0f, 0.0f, 0.0f, 1.0f } } };
         D3DMATRIX mat_projection =
         { { {
             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,
             (L+R)/(L-R),  (T+B)/(B-T),  0.5f,  1.0f
         } } };
         bd->pd3dDevice->SetTransform(D3DTS_WORLD, &mat_identity);
         bd->pd3dDevice->SetTransform(D3DTS_VIEW, &mat_identity);
         bd->pd3dDevice->SetTransform(D3DTS_PROJECTION, &mat_projection);
     }
 }

 // Render function.
 void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
 {
     // Avoid rendering when minimized
     if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
         return;

     // Create and grow buffers if needed
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     if (!bd->pVB || bd->VertexBufferSize < draw_data->TotalVtxCount)
     {
         if (bd->pVB) { bd->pVB->Release(); bd->pVB = NULL; }
         bd->VertexBufferSize = draw_data->TotalVtxCount + 5000;
         if (bd->pd3dDevice->CreateVertexBuffer(bd->VertexBufferSize * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &bd->pVB, NULL) < 0)
             return;
     }
     if (!bd->pIB || bd->IndexBufferSize < draw_data->TotalIdxCount)
     {
         if (bd->pIB) { bd->pIB->Release(); bd->pIB = NULL; }
         bd->IndexBufferSize = draw_data->TotalIdxCount + 10000;
         if (bd->pd3dDevice->CreateIndexBuffer(bd->IndexBufferSize * sizeof(ImDrawIdx), D3DUSAGE_DYNAMIC | D3DUSAGE_WRITEONLY, sizeof(ImDrawIdx) == 2 ? D3DFMT_INDEX16 : D3DFMT_INDEX32, D3DPOOL_DEFAULT, &bd->pIB, NULL) < 0)
             return;
     }

     // Backup the DX9 state
     IDirect3DStateBlock9* d3d9_state_block = NULL;
     if (bd->pd3dDevice->CreateStateBlock(D3DSBT_ALL, &d3d9_state_block) < 0)
         return;
     if (d3d9_state_block->Capture() < 0)
     {
         d3d9_state_block->Release();
         return;
     }

     // Backup the DX9 transform (DX9 documentation suggests that it is included in the StateBlock but it doesn't appear to)
     D3DMATRIX last_world, last_view, last_projection;
     bd->pd3dDevice->GetTransform(D3DTS_WORLD, &last_world);
     bd->pd3dDevice->GetTransform(D3DTS_VIEW, &last_view);
     bd->pd3dDevice->GetTransform(D3DTS_PROJECTION, &last_projection);

     // Allocate buffers
     CUSTOMVERTEX* vtx_dst;
     ImDrawIdx* idx_dst;
     if (bd->pVB->Lock(0, (UINT)(draw_data->TotalVtxCount * sizeof(CUSTOMVERTEX)), (void**)&vtx_dst, D3DLOCK_DISCARD) < 0)
     {
         d3d9_state_block->Release();
         return;
     }
     if (bd->pIB->Lock(0, (UINT)(draw_data->TotalIdxCount * sizeof(ImDrawIdx)), (void**)&idx_dst, D3DLOCK_DISCARD) < 0)
     {
         bd->pVB->Unlock();
         d3d9_state_block->Release();
         return;
     }

     // Copy and convert all vertices into a single contiguous buffer, convert colors to DX9 default format.
     // FIXME-OPT: This is a minor waste of resource, the ideal is to use imconfig.h and
     //  1) to avoid repacking colors:   #define IMGUI_USE_BGRA_PACKED_COLOR
     //  2) to avoid repacking vertices: #define IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT struct ImDrawVert { ImVec2 pos; float z; ImU32 col; ImVec2 uv; }
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_src = cmd_list->VtxBuffer.Data;
         for (int i = 0; i < cmd_list->VtxBuffer.Size; i++)
         {
             vtx_dst->pos[0] = vtx_src->pos.x;
             vtx_dst->pos[1] = vtx_src->pos.y;
             vtx_dst->pos[2] = 0.0f;
             vtx_dst->col = IMGUI_COL_TO_DX9_ARGB(vtx_src->col);
             vtx_dst->uv[0] = vtx_src->uv.x;
             vtx_dst->uv[1] = vtx_src->uv.y;
             vtx_dst++;
             vtx_src++;
         }
         memcpy(idx_dst, cmd_list->IdxBuffer.Data, cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         idx_dst += cmd_list->IdxBuffer.Size;
     }
     bd->pVB->Unlock();
     bd->pIB->Unlock();
     bd->pd3dDevice->SetStreamSource(0, bd->pVB, 0, sizeof(CUSTOMVERTEX));
     bd->pd3dDevice->SetIndices(bd->pIB);
     bd->pd3dDevice->SetFVF(D3DFVF_CUSTOMVERTEX);

     // Setup desired DX state
     ImGui_ImplDX9_SetupRenderState(draw_data);

     // 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_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 != NULL)
             {
                 // 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_ImplDX9_SetupRenderState(draw_data);
                 else
                     pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
                 const 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) };
                 const LPDIRECT3DTEXTURE9 texture = (LPDIRECT3DTEXTURE9)pcmd->GetTexID();
                 bd->pd3dDevice->SetTexture(0, texture);
                 bd->pd3dDevice->SetScissorRect(&r);
                 bd->pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, pcmd->VtxOffset + global_vtx_offset, 0, (UINT)cmd_list->VtxBuffer.Size, pcmd->IdxOffset + global_idx_offset, pcmd->ElemCount / 3);
             }
         }
         global_idx_offset += cmd_list->IdxBuffer.Size;
         global_vtx_offset += cmd_list->VtxBuffer.Size;
     }

     // Restore the DX9 transform
     bd->pd3dDevice->SetTransform(D3DTS_WORLD, &last_world);
     bd->pd3dDevice->SetTransform(D3DTS_VIEW, &last_view);
     bd->pd3dDevice->SetTransform(D3DTS_PROJECTION, &last_projection);

     // Restore the DX9 state
     d3d9_state_block->Apply();
     d3d9_state_block->Release();
 }

 bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
 {
     ImGuiIO& io = ImGui::GetIO();
     IM_ASSERT(io.BackendRendererUserData == NULL && "Already initialized a renderer backend!");

     // Setup backend capabilities flags
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_CreateBackendData();
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_dx9";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.

     bd->pd3dDevice = device;
     bd->pd3dDevice->AddRef();

     return true;
 }

 void ImGui_ImplDX9_Shutdown()
 {
     ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();

     ImGui_ImplDX9_InvalidateDeviceObjects();
     if (bd->pd3dDevice) { bd->pd3dDevice->Release(); bd->pd3dDevice = NULL; }
     io.BackendRendererName = NULL;
     io.BackendRendererUserData = NULL;
     ImGui_ImplDX9_DestroyBackendData();
 }

 static bool ImGui_ImplDX9_CreateFontsTexture()
 {
     // Build texture atlas
     ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     unsigned char* pixels;
     int width, height, bytes_per_pixel;
     io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &bytes_per_pixel);

     // Convert RGBA32 to BGRA32 (because RGBA32 is not well supported by DX9 devices)
 #ifndef IMGUI_USE_BGRA_PACKED_COLOR
     if (io.Fonts->TexPixelsUseColors)
     {
         ImU32* dst_start = (ImU32*)ImGui::MemAlloc((size_t)width * height * bytes_per_pixel);
         for (ImU32* src = (ImU32*)pixels, *dst = dst_start, *dst_end = dst_start + (size_t)width * height; dst < dst_end; src++, dst++)
             *dst = IMGUI_COL_TO_DX9_ARGB(*src);
         pixels = (unsigned char*)dst_start;
     }
 #endif

     // Upload texture to graphics system
     bd->FontTexture = NULL;
     if (bd->pd3dDevice->CreateTexture(width, height, 1, D3DUSAGE_DYNAMIC, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &bd->FontTexture, NULL) < 0)
         return false;
     D3DLOCKED_RECT tex_locked_rect;
     if (bd->FontTexture->LockRect(0, &tex_locked_rect, NULL, 0) != D3D_OK)
         return false;
     for (int y = 0; y < height; y++)
         memcpy((unsigned char*)tex_locked_rect.pBits + (size_t)tex_locked_rect.Pitch * y, pixels + (size_t)width * bytes_per_pixel * y, (size_t)width * bytes_per_pixel);
     bd->FontTexture->UnlockRect(0);

     // Store our identifier
     io.Fonts->SetTexID((ImTextureID)bd->FontTexture);

 #ifndef IMGUI_USE_BGRA_PACKED_COLOR
     if (io.Fonts->TexPixelsUseColors)
         ImGui::MemFree(pixels);
 #endif

     return true;
 }

 bool ImGui_ImplDX9_CreateDeviceObjects()
 {
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     if (!bd || !bd->pd3dDevice)
         return false;
     if (!ImGui_ImplDX9_CreateFontsTexture())
         return false;
     return true;
 }

 void ImGui_ImplDX9_InvalidateDeviceObjects()
 {
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     if (!bd || !bd->pd3dDevice)
         return;
     if (bd->pVB) { bd->pVB->Release(); bd->pVB = NULL; }
     if (bd->pIB) { bd->pIB->Release(); bd->pIB = NULL; }
     if (bd->FontTexture) { bd->FontTexture->Release(); bd->FontTexture = NULL; ImGui::GetIO().Fonts->SetTexID(NULL); } // We copied bd->pFontTextureView to io.Fonts->TexID so let's clear that as well.
 }

 void ImGui_ImplDX9_NewFrame()
 {
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     IM_ASSERT(bd != NULL && "Did you call ImGui_ImplDX9_Init()?");

     if (!bd->FontTexture)
         ImGui_ImplDX9_CreateDeviceObjects();
 }
	// dear imgui: Renderer Backend for DirectX9
	// This needs to be used along with a Platform Backend (e.g. Win32)

	// Implemented features:
	// [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' 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)
	// 2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
	// 2021-06-25: DirectX9: Explicitly disable texture state stages after >= 1.
	// 2021-05-19: DirectX9: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
	// 2021-04-23: DirectX9: Explicitly setting up more graphics states to increase compatibility with unusual non-default states.
	// 2021-03-18: DirectX9: Calling IDirect3DStateBlock9::Capture() after CreateStateBlock() as a workaround for state restoring issues (see #3857).
	// 2021-03-03: DirectX9: Added support for IMGUI_USE_BGRA_PACKED_COLOR in user's imconfig file.
	// 2021-02-18: DirectX9: Change blending equation to preserve alpha in output buffer.
	// 2019-05-29: DirectX9: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
	// 2019-04-30: DirectX9: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
	// 2019-03-29: Misc: Fixed erroneous assert in ImGui_ImplDX9_InvalidateDeviceObjects().
	// 2019-01-16: Misc: Disabled fog before drawing UI's. Fixes issue #2288.
	// 2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
	// 2018-06-08: Misc: Extracted imgui_impl_dx9.cpp/.h away from the old combined DX9+Win32 example.
	// 2018-06-08: DirectX9: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle.
	// 2018-05-07: Render: Saving/restoring Transform because they don't seem to be included in the StateBlock. Setting shading mode to Gouraud.
	// 2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplDX9_RenderDrawData() in the .h file so you can call it yourself.
	// 2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.

	#include "imgui.h"
	#include "imgui_impl_dx9.h"

	// DirectX
	#include <d3d9.h>

	// DirectX data
	struct ImGui_ImplDX9_Data
	{
	LPDIRECT3DDEVICE9 pd3dDevice;
	LPDIRECT3DVERTEXBUFFER9 pVB;
	LPDIRECT3DINDEXBUFFER9 pIB;
	LPDIRECT3DTEXTURE9 FontTexture;
	int VertexBufferSize;
	int IndexBufferSize;

	ImGui_ImplDX9_Data() { memset(this, 0, sizeof(*this)); VertexBufferSize = 5000; IndexBufferSize = 10000; }
	};

	// Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
	// It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
	static ImGui_ImplDX9_Data* ImGui_ImplDX9_CreateBackendData() { return IM_NEW(ImGui_ImplDX9_Data)(); }
	static ImGui_ImplDX9_Data* ImGui_ImplDX9_GetBackendData() { return (ImGui_ImplDX9_Data*)ImGui::GetIO().BackendRendererUserData; }
	static void ImGui_ImplDX9_DestroyBackendData() { IM_DELETE(ImGui_ImplDX9_GetBackendData()); }

	struct CUSTOMVERTEX
	{
	float pos[3];
	D3DCOLOR col;
	float uv[2];
	};
	#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ\|D3DFVF_DIFFUSE\|D3DFVF_TEX1)

	#ifdef IMGUI_USE_BGRA_PACKED_COLOR
	#define IMGUI_COL_TO_DX9_ARGB(_COL) (_COL)
	#else
	#define IMGUI_COL_TO_DX9_ARGB(_COL) (((_COL) & 0xFF00FF00) \| (((_COL) & 0xFF0000) >> 16) \| (((_COL) & 0xFF) << 16))
	#endif

	// Functions
	static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
	{
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();

	// Setup viewport
	D3DVIEWPORT9 vp;
	vp.X = vp.Y = 0;
	vp.Width = (DWORD)draw_data->DisplaySize.x;
	vp.Height = (DWORD)draw_data->DisplaySize.y;
	vp.MinZ = 0.0f;
	vp.MaxZ = 1.0f;
	bd->pd3dDevice->SetViewport(&vp);

	// Setup render state: fixed-pipeline, alpha-blending, no face culling, no depth testing, shade mode (for gradient)
	bd->pd3dDevice->SetPixelShader(NULL);
	bd->pd3dDevice->SetVertexShader(NULL);
	bd->pd3dDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_SOLID);
	bd->pd3dDevice->SetRenderState(D3DRS_SHADEMODE, D3DSHADE_GOURAUD);
	bd->pd3dDevice->SetRenderState(D3DRS_ZWRITEENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_ALPHATESTENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
	bd->pd3dDevice->SetRenderState(D3DRS_ZENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
	bd->pd3dDevice->SetRenderState(D3DRS_BLENDOP, D3DBLENDOP_ADD);
	bd->pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
	bd->pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
	bd->pd3dDevice->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);
	bd->pd3dDevice->SetRenderState(D3DRS_SRCBLENDALPHA, D3DBLEND_ONE);
	bd->pd3dDevice->SetRenderState(D3DRS_DESTBLENDALPHA, D3DBLEND_INVSRCALPHA);
	bd->pd3dDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, TRUE);
	bd->pd3dDevice->SetRenderState(D3DRS_FOGENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_RANGEFOGENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_SPECULARENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_STENCILENABLE, FALSE);
	bd->pd3dDevice->SetRenderState(D3DRS_CLIPPING, TRUE);
	bd->pd3dDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
	bd->pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);
	bd->pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
	bd->pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);
	bd->pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
	bd->pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
	bd->pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE);
	bd->pd3dDevice->SetTextureStageState(1, D3DTSS_COLOROP, D3DTOP_DISABLE);
	bd->pd3dDevice->SetTextureStageState(1, D3DTSS_ALPHAOP, D3DTOP_DISABLE);
	bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
	bd->pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);

	// Setup orthographic projection matrix
	// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
	// Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
	{
	float L = draw_data->DisplayPos.x + 0.5f;
	float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x + 0.5f;
	float T = draw_data->DisplayPos.y + 0.5f;
	float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y + 0.5f;
	D3DMATRIX mat_identity = { { { 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f } } };
	D3DMATRIX mat_projection =
	{ { {
	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,
	(L+R)/(L-R), (T+B)/(B-T), 0.5f, 1.0f
	} } };
	bd->pd3dDevice->SetTransform(D3DTS_WORLD, &mat_identity);
	bd->pd3dDevice->SetTransform(D3DTS_VIEW, &mat_identity);
	bd->pd3dDevice->SetTransform(D3DTS_PROJECTION, &mat_projection);
	}
	}

	// Render function.
	void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
	{
	// Avoid rendering when minimized
	if (draw_data->DisplaySize.x <= 0.0f \|\| draw_data->DisplaySize.y <= 0.0f)
	return;

	// Create and grow buffers if needed
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
	if (!bd->pVB \|\| bd->VertexBufferSize < draw_data->TotalVtxCount)
	{
	if (bd->pVB) { bd->pVB->Release(); bd->pVB = NULL; }
	bd->VertexBufferSize = draw_data->TotalVtxCount + 5000;
	if (bd->pd3dDevice->CreateVertexBuffer(bd->VertexBufferSize * sizeof(CUSTOMVERTEX), D3DUSAGE_DYNAMIC \| D3DUSAGE_WRITEONLY, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &bd->pVB, NULL) < 0)
	return;
	}
	if (!bd->pIB \|\| bd->IndexBufferSize < draw_data->TotalIdxCount)
	{
	if (bd->pIB) { bd->pIB->Release(); bd->pIB = NULL; }
	bd->IndexBufferSize = draw_data->TotalIdxCount + 10000;
	if (bd->pd3dDevice->CreateIndexBuffer(bd->IndexBufferSize * sizeof(ImDrawIdx), D3DUSAGE_DYNAMIC \| D3DUSAGE_WRITEONLY, sizeof(ImDrawIdx) == 2 ? D3DFMT_INDEX16 : D3DFMT_INDEX32, D3DPOOL_DEFAULT, &bd->pIB, NULL) < 0)
	return;
	}

	// Backup the DX9 state
	IDirect3DStateBlock9* d3d9_state_block = NULL;
	if (bd->pd3dDevice->CreateStateBlock(D3DSBT_ALL, &d3d9_state_block) < 0)
	return;
	if (d3d9_state_block->Capture() < 0)
	{
	d3d9_state_block->Release();
	return;
	}

	// Backup the DX9 transform (DX9 documentation suggests that it is included in the StateBlock but it doesn't appear to)
	D3DMATRIX last_world, last_view, last_projection;
	bd->pd3dDevice->GetTransform(D3DTS_WORLD, &last_world);
	bd->pd3dDevice->GetTransform(D3DTS_VIEW, &last_view);
	bd->pd3dDevice->GetTransform(D3DTS_PROJECTION, &last_projection);

	// Allocate buffers
	CUSTOMVERTEX* vtx_dst;
	ImDrawIdx* idx_dst;
	if (bd->pVB->Lock(0, (UINT)(draw_data->TotalVtxCount * sizeof(CUSTOMVERTEX)), (void**)&vtx_dst, D3DLOCK_DISCARD) < 0)
	{
	d3d9_state_block->Release();
	return;
	}
	if (bd->pIB->Lock(0, (UINT)(draw_data->TotalIdxCount * sizeof(ImDrawIdx)), (void**)&idx_dst, D3DLOCK_DISCARD) < 0)
	{
	bd->pVB->Unlock();
	d3d9_state_block->Release();
	return;
	}

	// Copy and convert all vertices into a single contiguous buffer, convert colors to DX9 default format.
	// FIXME-OPT: This is a minor waste of resource, the ideal is to use imconfig.h and
	// 1) to avoid repacking colors: #define IMGUI_USE_BGRA_PACKED_COLOR
	// 2) to avoid repacking vertices: #define IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT struct ImDrawVert { ImVec2 pos; float z; ImU32 col; ImVec2 uv; }
	for (int n = 0; n < draw_data->CmdListsCount; n++)
	{
	const ImDrawList* cmd_list = draw_data->CmdLists[n];
	const ImDrawVert* vtx_src = cmd_list->VtxBuffer.Data;
	for (int i = 0; i < cmd_list->VtxBuffer.Size; i++)
	{
	vtx_dst->pos[0] = vtx_src->pos.x;
	vtx_dst->pos[1] = vtx_src->pos.y;
	vtx_dst->pos[2] = 0.0f;
	vtx_dst->col = IMGUI_COL_TO_DX9_ARGB(vtx_src->col);
	vtx_dst->uv[0] = vtx_src->uv.x;
	vtx_dst->uv[1] = vtx_src->uv.y;
	vtx_dst++;
	vtx_src++;
	}
	memcpy(idx_dst, cmd_list->IdxBuffer.Data, cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx));
	idx_dst += cmd_list->IdxBuffer.Size;
	}
	bd->pVB->Unlock();
	bd->pIB->Unlock();
	bd->pd3dDevice->SetStreamSource(0, bd->pVB, 0, sizeof(CUSTOMVERTEX));
	bd->pd3dDevice->SetIndices(bd->pIB);
	bd->pd3dDevice->SetFVF(D3DFVF_CUSTOMVERTEX);

	// Setup desired DX state
	ImGui_ImplDX9_SetupRenderState(draw_data);

	// 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_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 != NULL)
	{
	// 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_ImplDX9_SetupRenderState(draw_data);
	else
	pcmd->UserCallback(cmd_list, pcmd);
	}
	else
	{
	const 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) };
	const LPDIRECT3DTEXTURE9 texture = (LPDIRECT3DTEXTURE9)pcmd->GetTexID();
	bd->pd3dDevice->SetTexture(0, texture);
	bd->pd3dDevice->SetScissorRect(&r);
	bd->pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, pcmd->VtxOffset + global_vtx_offset, 0, (UINT)cmd_list->VtxBuffer.Size, pcmd->IdxOffset + global_idx_offset, pcmd->ElemCount / 3);
	}
	}
	global_idx_offset += cmd_list->IdxBuffer.Size;
	global_vtx_offset += cmd_list->VtxBuffer.Size;
	}

	// Restore the DX9 transform
	bd->pd3dDevice->SetTransform(D3DTS_WORLD, &last_world);
	bd->pd3dDevice->SetTransform(D3DTS_VIEW, &last_view);
	bd->pd3dDevice->SetTransform(D3DTS_PROJECTION, &last_projection);

	// Restore the DX9 state
	d3d9_state_block->Apply();
	d3d9_state_block->Release();
	}

	bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
	{
	ImGuiIO& io = ImGui::GetIO();
	IM_ASSERT(io.BackendRendererUserData == NULL && "Already initialized a renderer backend!");

	// Setup backend capabilities flags
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_CreateBackendData();
	io.BackendRendererUserData = (void*)bd;
	io.BackendRendererName = "imgui_impl_dx9";
	io.BackendFlags \|= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.

	bd->pd3dDevice = device;
	bd->pd3dDevice->AddRef();

	return true;
	}

	void ImGui_ImplDX9_Shutdown()
	{
	ImGuiIO& io = ImGui::GetIO();
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();

	ImGui_ImplDX9_InvalidateDeviceObjects();
	if (bd->pd3dDevice) { bd->pd3dDevice->Release(); bd->pd3dDevice = NULL; }
	io.BackendRendererName = NULL;
	io.BackendRendererUserData = NULL;
	ImGui_ImplDX9_DestroyBackendData();
	}

	static bool ImGui_ImplDX9_CreateFontsTexture()
	{
	// Build texture atlas
	ImGuiIO& io = ImGui::GetIO();
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
	unsigned char* pixels;
	int width, height, bytes_per_pixel;
	io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &bytes_per_pixel);

	// Convert RGBA32 to BGRA32 (because RGBA32 is not well supported by DX9 devices)
	#ifndef IMGUI_USE_BGRA_PACKED_COLOR
	if (io.Fonts->TexPixelsUseColors)
	{
	ImU32* dst_start = (ImU32)ImGui::MemAlloc((size_t)width height * bytes_per_pixel);
	for (ImU32* src = (ImU32)pixels, dst = dst_start, dst_end = dst_start + (size_t)width height; dst < dst_end; src++, dst++)
	dst = IMGUI_COL_TO_DX9_ARGB(src);
	pixels = (unsigned char*)dst_start;
	}
	#endif

	// Upload texture to graphics system
	bd->FontTexture = NULL;
	if (bd->pd3dDevice->CreateTexture(width, height, 1, D3DUSAGE_DYNAMIC, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &bd->FontTexture, NULL) < 0)
	return false;
	D3DLOCKED_RECT tex_locked_rect;
	if (bd->FontTexture->LockRect(0, &tex_locked_rect, NULL, 0) != D3D_OK)
	return false;
	for (int y = 0; y < height; y++)
	memcpy((unsigned char)tex_locked_rect.pBits + (size_t)tex_locked_rect.Pitch y, pixels + (size_t)width * bytes_per_pixel * y, (size_t)width * bytes_per_pixel);
	bd->FontTexture->UnlockRect(0);

	// Store our identifier
	io.Fonts->SetTexID((ImTextureID)bd->FontTexture);

	#ifndef IMGUI_USE_BGRA_PACKED_COLOR
	if (io.Fonts->TexPixelsUseColors)
	ImGui::MemFree(pixels);
	#endif

	return true;
	}

	bool ImGui_ImplDX9_CreateDeviceObjects()
	{
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
	if (!bd \|\| !bd->pd3dDevice)
	return false;
	if (!ImGui_ImplDX9_CreateFontsTexture())
	return false;
	return true;
	}

	void ImGui_ImplDX9_InvalidateDeviceObjects()
	{
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
	if (!bd \|\| !bd->pd3dDevice)
	return;
	if (bd->pVB) { bd->pVB->Release(); bd->pVB = NULL; }
	if (bd->pIB) { bd->pIB->Release(); bd->pIB = NULL; }
	if (bd->FontTexture) { bd->FontTexture->Release(); bd->FontTexture = NULL; ImGui::GetIO().Fonts->SetTexID(NULL); } // We copied bd->pFontTextureView to io.Fonts->TexID so let's clear that as well.
	}

	void ImGui_ImplDX9_NewFrame()
	{
	ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
	IM_ASSERT(bd != NULL && "Did you call ImGui_ImplDX9_Init()?");

	if (!bd->FontTexture)
	ImGui_ImplDX9_CreateDeviceObjects();
	}