| // dear imgui: Renderer Backend for SDL_Renderer |
| // (Requires: SDL 2.0.17+) |
| |
| // Important to understand: SDL_Renderer is an _optional_ component of SDL. |
| // For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX. |
| // If your application will want to render any non trivial amount of graphics other than UI, |
| // please be aware that SDL_Renderer offers a limited graphic API to the end-user and it might |
| // be difficult to step out of those boundaries. |
| // However, we understand it is a convenient choice to get an app started easily. |
| |
| // Implemented features: |
| // [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID! |
| // [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices. |
| // Missing features: |
| // [ ] Renderer: Multi-viewport support (multiple windows). |
| |
| // You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. |
| // 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 |
| // 2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11. |
| // 2021-12-21: Update SDL_RenderGeometryRaw() format to work with SDL 2.0.19. |
| // 2021-12-03: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag. |
| // 2021-10-06: Backup and restore modified ClipRect/Viewport. |
| // 2021-09-21: Initial version. |
| |
| #include "imgui.h" |
| #include "imgui_impl_sdlrenderer.h" |
| #if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier |
| #include <stddef.h> // intptr_t |
| #else |
| #include <stdint.h> // intptr_t |
| #endif |
| |
| // Clang warnings with -Weverything |
| #if defined(__clang__) |
| #pragma clang diagnostic push |
| #pragma clang diagnostic ignored "-Wsign-conversion" // warning: implicit conversion changes signedness |
| #endif |
| |
| // SDL |
| #include <SDL.h> |
| #if !SDL_VERSION_ATLEAST(2,0,17) |
| #error This backend requires SDL 2.0.17+ because of SDL_RenderGeometry() function |
| #endif |
| |
| // SDL_Renderer data |
| struct ImGui_ImplSDLRenderer_Data |
| { |
| SDL_Renderer* SDLRenderer; |
| SDL_Texture* FontTexture; |
| ImGui_ImplSDLRenderer_Data() { memset((void*)this, 0, sizeof(*this)); } |
| }; |
| |
| // 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_ImplSDLRenderer_Data* ImGui_ImplSDLRenderer_GetBackendData() |
| { |
| return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer_Data*)ImGui::GetIO().BackendRendererUserData : nullptr; |
| } |
| |
| // Functions |
| bool ImGui_ImplSDLRenderer_Init(SDL_Renderer* renderer) |
| { |
| ImGuiIO& io = ImGui::GetIO(); |
| IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!"); |
| IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!"); |
| |
| // Setup backend capabilities flags |
| ImGui_ImplSDLRenderer_Data* bd = IM_NEW(ImGui_ImplSDLRenderer_Data)(); |
| io.BackendRendererUserData = (void*)bd; |
| io.BackendRendererName = "imgui_impl_sdlrenderer"; |
| io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes. |
| |
| bd->SDLRenderer = renderer; |
| |
| return true; |
| } |
| |
| void ImGui_ImplSDLRenderer_Shutdown() |
| { |
| ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData(); |
| IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?"); |
| ImGuiIO& io = ImGui::GetIO(); |
| |
| ImGui_ImplSDLRenderer_DestroyDeviceObjects(); |
| |
| io.BackendRendererName = nullptr; |
| io.BackendRendererUserData = nullptr; |
| IM_DELETE(bd); |
| } |
| |
| static void ImGui_ImplSDLRenderer_SetupRenderState() |
| { |
| ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData(); |
| |
| // Clear out any viewports and cliprect set by the user |
| // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process. |
| SDL_RenderSetViewport(bd->SDLRenderer, nullptr); |
| SDL_RenderSetClipRect(bd->SDLRenderer, nullptr); |
| } |
| |
| void ImGui_ImplSDLRenderer_NewFrame() |
| { |
| ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData(); |
| IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplSDLRenderer_Init()?"); |
| |
| if (!bd->FontTexture) |
| ImGui_ImplSDLRenderer_CreateDeviceObjects(); |
| } |
| |
| void ImGui_ImplSDLRenderer_RenderDrawData(ImDrawData* draw_data) |
| { |
| ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData(); |
| |
| // If there's a scale factor set by the user, use that instead |
| // If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass |
| // to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here. |
| float rsx = 1.0f; |
| float rsy = 1.0f; |
| SDL_RenderGetScale(bd->SDLRenderer, &rsx, &rsy); |
| ImVec2 render_scale; |
| render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f; |
| render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f; |
| |
| // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates) |
| int fb_width = (int)(draw_data->DisplaySize.x * render_scale.x); |
| int fb_height = (int)(draw_data->DisplaySize.y * render_scale.y); |
| if (fb_width == 0 || fb_height == 0) |
| return; |
| |
| // Backup SDL_Renderer state that will be modified to restore it afterwards |
| struct BackupSDLRendererState |
| { |
| SDL_Rect Viewport; |
| bool ClipEnabled; |
| SDL_Rect ClipRect; |
| }; |
| BackupSDLRendererState old = {}; |
| old.ClipEnabled = SDL_RenderIsClipEnabled(bd->SDLRenderer) == SDL_TRUE; |
| SDL_RenderGetViewport(bd->SDLRenderer, &old.Viewport); |
| SDL_RenderGetClipRect(bd->SDLRenderer, &old.ClipRect); |
| |
| // Will project scissor/clipping rectangles into framebuffer space |
| ImVec2 clip_off = draw_data->DisplayPos; // (0,0) unless using multi-viewports |
| ImVec2 clip_scale = render_scale; |
| |
| // Render command lists |
| ImGui_ImplSDLRenderer_SetupRenderState(); |
| for (int n = 0; n < draw_data->CmdListsCount; n++) |
| { |
| const ImDrawList* cmd_list = draw_data->CmdLists[n]; |
| const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data; |
| const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data; |
| |
| for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++) |
| { |
| const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i]; |
| if (pcmd->UserCallback) |
| { |
| // 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_ImplSDLRenderer_SetupRenderState(); |
| else |
| pcmd->UserCallback(cmd_list, pcmd); |
| } |
| else |
| { |
| // Project scissor/clipping rectangles into framebuffer space |
| ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y); |
| ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y); |
| if (clip_min.x < 0.0f) { clip_min.x = 0.0f; } |
| if (clip_min.y < 0.0f) { clip_min.y = 0.0f; } |
| if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; } |
| if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; } |
| if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y) |
| continue; |
| |
| SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) }; |
| SDL_RenderSetClipRect(bd->SDLRenderer, &r); |
| |
| const float* xy = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, pos)); |
| const float* uv = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, uv)); |
| #if SDL_VERSION_ATLEAST(2,0,19) |
| const SDL_Color* color = (const SDL_Color*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, col)); // SDL 2.0.19+ |
| #else |
| const int* color = (const int*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, col)); // SDL 2.0.17 and 2.0.18 |
| #endif |
| |
| // Bind texture, Draw |
| SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID(); |
| SDL_RenderGeometryRaw(bd->SDLRenderer, tex, |
| xy, (int)sizeof(ImDrawVert), |
| color, (int)sizeof(ImDrawVert), |
| uv, (int)sizeof(ImDrawVert), |
| cmd_list->VtxBuffer.Size - pcmd->VtxOffset, |
| idx_buffer + pcmd->IdxOffset, pcmd->ElemCount, sizeof(ImDrawIdx)); |
| } |
| } |
| } |
| |
| // Restore modified SDL_Renderer state |
| SDL_RenderSetViewport(bd->SDLRenderer, &old.Viewport); |
| SDL_RenderSetClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : nullptr); |
| } |
| |
| // Called by Init/NewFrame/Shutdown |
| bool ImGui_ImplSDLRenderer_CreateFontsTexture() |
| { |
| ImGuiIO& io = ImGui::GetIO(); |
| ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData(); |
| |
| // Build texture atlas |
| unsigned char* pixels; |
| int width, height; |
| io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory. |
| |
| // Upload texture to graphics system |
| // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling) |
| bd->FontTexture = SDL_CreateTexture(bd->SDLRenderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height); |
| if (bd->FontTexture == nullptr) |
| { |
| SDL_Log("error creating texture"); |
| return false; |
| } |
| SDL_UpdateTexture(bd->FontTexture, nullptr, pixels, 4 * width); |
| SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND); |
| SDL_SetTextureScaleMode(bd->FontTexture, SDL_ScaleModeLinear); |
| |
| // Store our identifier |
| io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture); |
| |
| return true; |
| } |
| |
| void ImGui_ImplSDLRenderer_DestroyFontsTexture() |
| { |
| ImGuiIO& io = ImGui::GetIO(); |
| ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData(); |
| if (bd->FontTexture) |
| { |
| io.Fonts->SetTexID(0); |
| SDL_DestroyTexture(bd->FontTexture); |
| bd->FontTexture = nullptr; |
| } |
| } |
| |
| bool ImGui_ImplSDLRenderer_CreateDeviceObjects() |
| { |
| return ImGui_ImplSDLRenderer_CreateFontsTexture(); |
| } |
| |
| void ImGui_ImplSDLRenderer_DestroyDeviceObjects() |
| { |
| ImGui_ImplSDLRenderer_DestroyFontsTexture(); |
| } |
| |
| #if defined(__clang__) |
| #pragma clang diagnostic pop |
| #endif |