Examples/Backends: DirectX9/10/11/12, Vulkan, OpenGL3 (Desktop GL only): Added support for large meshes (64k+ vertices) with 16-bits indices, enable 'ImGuiBackendFlags_HasVtxOffset' config flag in back-end. (#2591)

docs/CHANGELOG.txt

@@ -71,6 +71,8 @@ Other Changes:
 - Backends: Add native Mac clipboard copy/paste default implementation in core library to match what we are
   dealing with Win32, and to facilitate integration in custom engines. (#2546) [@andrewwillmott]
 - Backends: OSX: imgui_impl_osx: Added mouse cursor support. (#2585, #1873) [@actboy168]
+- Examples/Backends: DirectX9/10/11/12, Vulkan, OpenGL3 (Desktop GL only): Added support for large meshes
+  (64k+ vertices) with 16-bits indices, enable 'ImGuiBackendFlags_HasVtxOffset' config flag in back-end.
 - Examples/Backends: Don't filter characters under 0x10000 before calling io.AddInputCharacter(),
   the filtering is done in io.AddInputCharacter() itself. This is in prevision for fuller Unicode
   support. (#2538, #2541)

examples/imgui_impl_dx10.cpp

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
@@ -10,6 +11,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-05-29: DirectX10: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_HasVtxOffset flag.
 //  2019-04-30: DirectX10: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
@@ -208,8 +210,9 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX10_SetupRenderState(draw_data, ctx);
 
     // Render command lists
-    int vtx_offset = 0;
-    int idx_offset = 0;
+    // (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++)
     {
@@ -235,11 +238,11 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
                 // Bind texture, Draw
                 ID3D10ShaderResourceView* texture_srv = (ID3D10ShaderResourceView*)pcmd->TextureId;
                 ctx->PSSetShaderResources(0, 1, &texture_srv);
-                ctx->DrawIndexed(pcmd->ElemCount, idx_offset, vtx_offset);
+                ctx->DrawIndexed(pcmd->ElemCount, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset);
             }
-            idx_offset += pcmd->ElemCount;
         }
-        vtx_offset += cmd_list->VtxBuffer.Size;
+        global_idx_offset += cmd_list->IdxBuffer.Size;
+        global_vtx_offset += cmd_list->VtxBuffer.Size;
     }
 
     // Restore modified DX state
@@ -485,6 +488,7 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
 {
     ImGuiIO& io = ImGui::GetIO();
     io.BackendRendererName = "imgui_impl_dx10";
+    io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset;      // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = NULL;

examples/imgui_impl_dx10.h

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.

examples/imgui_impl_dx11.cpp

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp
@@ -10,6 +11,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-05-29: DirectX11: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_HasVtxOffset flag.
 //  2019-04-30: DirectX11: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
@@ -213,8 +215,9 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX11_SetupRenderState(draw_data, ctx);
 
     // Render command lists
-    int vtx_offset = 0;
-    int idx_offset = 0;
+    // (Because we merged all buffers into a single one, we maintain our own offset into them)
+    int global_idx_offset = 0;
+    int global_vtx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
@@ -240,11 +243,11 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
                 // Bind texture, Draw
                 ID3D11ShaderResourceView* texture_srv = (ID3D11ShaderResourceView*)pcmd->TextureId;
                 ctx->PSSetShaderResources(0, 1, &texture_srv);
-                ctx->DrawIndexed(pcmd->ElemCount, idx_offset, vtx_offset);
+                ctx->DrawIndexed(pcmd->ElemCount, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset);
             }
-            idx_offset += pcmd->ElemCount;
         }
-        vtx_offset += cmd_list->VtxBuffer.Size;
+        global_idx_offset += cmd_list->IdxBuffer.Size;
+        global_vtx_offset += cmd_list->VtxBuffer.Size;
     }
 
     // Restore modified DX state
@@ -492,6 +495,7 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
 {
     ImGuiIO& io = ImGui::GetIO();
     io.BackendRendererName = "imgui_impl_dx11";
+    io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset;      // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = NULL;

examples/imgui_impl_dx11.h

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.

examples/imgui_impl_dx12.cpp

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 // Issues:
 //  [ ] 64-bit only for now! (Because sizeof(ImTextureId) == sizeof(void*)). See github.com/ocornut/imgui/pull/301
 
@@ -12,6 +13,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-05-29: DirectX12: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_HasVtxOffset flag.
 //  2019-04-30: DirectX12: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-03-29: Misc: Various minor tidying up.
 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
@@ -200,8 +202,9 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     ImGui_ImplDX12_SetupRenderState(draw_data, ctx, fr);
 
     // Render command lists
-    int vtx_offset = 0;
-    int idx_offset = 0;
+    // (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++)
     {
@@ -224,11 +227,11 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
                 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) };
                 ctx->SetGraphicsRootDescriptorTable(1, *(D3D12_GPU_DESCRIPTOR_HANDLE*)&pcmd->TextureId);
                 ctx->RSSetScissorRects(1, &r);
-                ctx->DrawIndexedInstanced(pcmd->ElemCount, 1, idx_offset, vtx_offset, 0);
+                ctx->DrawIndexedInstanced(pcmd->ElemCount, 1, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset, 0);
             }
-            idx_offset += pcmd->ElemCount;
         }
-        vtx_offset += cmd_list->VtxBuffer.Size;
+        global_idx_offset += cmd_list->IdxBuffer.Size;
+        global_vtx_offset += cmd_list->VtxBuffer.Size;
     }
 }
 
@@ -604,6 +607,7 @@ bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FO
 {
     ImGuiIO& io = ImGui::GetIO();
     io.BackendRendererName = "imgui_impl_dx12";
+    io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset;      // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
     g_pd3dDevice = device;
     g_RTVFormat = rtv_format;

examples/imgui_impl_dx12.h

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 // Issues:
 //  [ ] 64-bit only for now! (Because sizeof(ImTextureId) == sizeof(void*)). See github.com/ocornut/imgui/pull/301
 

examples/imgui_impl_dx9.cpp

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
@@ -10,6 +11,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-05-29: DirectX9: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_HasVtxOffset 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.
@@ -172,8 +174,9 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX9_SetupRenderState(draw_data);
 
     // Render command lists
-    int vtx_offset = 0;
-    int idx_offset = 0;
+    // (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++)
     {
@@ -196,11 +199,11 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
                 const LPDIRECT3DTEXTURE9 texture = (LPDIRECT3DTEXTURE9)pcmd->TextureId;
                 g_pd3dDevice->SetTexture(0, texture);
                 g_pd3dDevice->SetScissorRect(&r);
-                g_pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, vtx_offset, 0, (UINT)cmd_list->VtxBuffer.Size, idx_offset, pcmd->ElemCount/3);
+                g_pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, pcmd->VtxOffset + global_vtx_offset, 0, (UINT)cmd_list->VtxBuffer.Size, pcmd->IdxOffset + global_idx_offset, pcmd->ElemCount/3);
             }
-            idx_offset += pcmd->ElemCount;
         }
-        vtx_offset += cmd_list->VtxBuffer.Size;
+        global_idx_offset += cmd_list->IdxBuffer.Size;
+        global_vtx_offset += cmd_list->VtxBuffer.Size;
     }
 
     // Restore the DX9 transform
@@ -217,6 +220,7 @@ bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
 {
     ImGuiIO& io = ImGui::GetIO();
     io.BackendRendererName = "imgui_impl_dx9";
+    io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset;      // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
     g_pd3dDevice = device;
     g_pd3dDevice->AddRef();

examples/imgui_impl_dx9.h

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.

examples/imgui_impl_opengl3.cpp

@@ -5,6 +5,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
@@ -12,6 +13,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-05-29: OpenGL: Desktop GL only: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_HasVtxOffset flag.
 //  2019-04-30: OpenGL: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-03-29: OpenGL: Not calling glBindBuffer more than necessary in the render loop.
 //  2019-03-15: OpenGL: Added a dummy GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized GL function loaders early.
@@ -102,6 +104,13 @@
 #endif
 #endif
 
+// Desktop GL has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
+#if defined(IMGUI_IMPL_OPENGL_ES2) || defined(IMGUI_IMPL_OPENGL_ES3)
+#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     1
+#else
+#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     0
+#endif
+
 // OpenGL Data
 static char         g_GlslVersionString[32] = "";
 static GLuint       g_FontTexture = 0;
@@ -263,7 +272,6 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
-        size_t idx_buffer_offset = 0;
 
         // Upload vertex/index buffers
         glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
@@ -300,10 +308,13 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
 
                     // Bind texture, Draw
                     glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
-                    glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)idx_buffer_offset);
+#if IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX
+                    glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)pcmd->IdxOffset, (GLint)pcmd->VtxOffset);
+#else
+                    glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)pcmd->IdxOffset);
+#endif
                 }
             }
-            idx_buffer_offset += pcmd->ElemCount * sizeof(ImDrawIdx);
         }
     }
 

examples/imgui_impl_opengl3.h

@@ -5,6 +5,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
+//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bits indices.
 
 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.

examples/imgui_impl_vulkan.cpp

@@ -1,6 +1,8 @@
 // dear imgui: Renderer for Vulkan
 // This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
 
+// Implemented features:
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 // Missing features:
 //  [ ] Renderer: User texture binding. Changes of ImTextureID aren't supported by this binding! See https://github.com/ocornut/imgui/pull/914
 
@@ -20,6 +22,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-05-29: Vulkan: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_HasVtxOffset flag.
 //  2019-04-30: Vulkan: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-04-04: *BREAKING CHANGE*: Vulkan: Added ImageCount/MinImageCount fields in ImGui_ImplVulkan_InitInfo, required for initialization (was previously a hard #define IMGUI_VK_QUEUED_FRAMES 2). Added ImGui_ImplVulkan_SetMinImageCount().
 //  2019-04-04: Vulkan: Added VkInstance argument to ImGui_ImplVulkanH_CreateWindow() optional helper.
@@ -375,8 +378,9 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
     ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
     // Render command lists
-    int vtx_offset = 0;
-    int idx_offset = 0;
+    // (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;
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
@@ -418,12 +422,12 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
                     vkCmdSetScissor(command_buffer, 0, 1, &scissor);
 
                     // Draw
-                    vkCmdDrawIndexed(command_buffer, pcmd->ElemCount, 1, idx_offset, vtx_offset, 0);
+                    vkCmdDrawIndexed(command_buffer, pcmd->ElemCount, 1, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset, 0);
                 }
             }
-            idx_offset += pcmd->ElemCount;
         }
-        vtx_offset += cmd_list->VtxBuffer.Size;
+        global_idx_offset += cmd_list->IdxBuffer.Size;
+        global_vtx_offset += cmd_list->VtxBuffer.Size;
     }
 }
 
@@ -801,6 +805,7 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info, VkRenderPass rend
 {
     ImGuiIO& io = ImGui::GetIO();
     io.BackendRendererName = "imgui_impl_vulkan";
+    io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset;      // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
     IM_ASSERT(info->Instance != VK_NULL_HANDLE);
     IM_ASSERT(info->PhysicalDevice != VK_NULL_HANDLE);

examples/imgui_impl_vulkan.h

@@ -1,6 +1,8 @@
 // dear imgui: Renderer for Vulkan
 // This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
 
+// Implemented features:
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bits indices.
 // Missing features:
 //  [ ] Renderer: User texture binding. Changes of ImTextureID aren't supported by this binding! See https://github.com/ocornut/imgui/pull/914