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Diffstat (limited to 'src/imgui/backends/imgui_impl_sdlrenderer3.cpp')
| -rw-r--r-- | src/imgui/backends/imgui_impl_sdlrenderer3.cpp | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/src/imgui/backends/imgui_impl_sdlrenderer3.cpp b/src/imgui/backends/imgui_impl_sdlrenderer3.cpp new file mode 100644 index 0000000..fcef4f5 --- /dev/null +++ b/src/imgui/backends/imgui_impl_sdlrenderer3.cpp @@ -0,0 +1,261 @@ +// dear imgui: Renderer Backend for SDL_Renderer for SDL3 +// (Requires: SDL 3.0.0+) + +// Note how SDL_Renderer is an _optional_ component of SDL3. +// 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 currently offers a limited graphic API to the end-user and +// it might be difficult to step out of those boundaries. + +// 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. + +// You can copy and 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. +// Learn about Dear ImGui: +// - FAQ https://dearimgui.com/faq +// - Getting Started https://dearimgui.com/getting-started +// - Documentation https://dearimgui.com/docs (same as your local docs/ folder). +// - Introduction, links and more at the top of imgui.cpp + +// CHANGELOG +// 2023-05-30: Initial version. + +#include "imgui.h" +#ifndef IMGUI_DISABLE +#include "imgui_impl_sdlrenderer3.h" +#include <stdint.h> // intptr_t + +// 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 <SDL3/SDL.h> +#if !SDL_VERSION_ATLEAST(3,0,0) +#error This backend requires SDL 3.0.0+ +#endif + +// SDL_Renderer data +struct ImGui_ImplSDLRenderer3_Data +{ + SDL_Renderer* SDLRenderer; + SDL_Texture* FontTexture; + ImGui_ImplSDLRenderer3_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_ImplSDLRenderer3_Data* ImGui_ImplSDLRenderer3_GetBackendData() +{ + return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr; +} + +// Functions +bool ImGui_ImplSDLRenderer3_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_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)(); + io.BackendRendererUserData = (void*)bd; + io.BackendRendererName = "imgui_impl_sdlrenderer3"; + io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes. + + bd->SDLRenderer = renderer; + + return true; +} + +void ImGui_ImplSDLRenderer3_Shutdown() +{ + ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData(); + IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?"); + ImGuiIO& io = ImGui::GetIO(); + + ImGui_ImplSDLRenderer3_DestroyDeviceObjects(); + + io.BackendRendererName = nullptr; + io.BackendRendererUserData = nullptr; + io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset; + IM_DELETE(bd); +} + +static void ImGui_ImplSDLRenderer3_SetupRenderState() +{ + ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_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_SetRenderViewport(bd->SDLRenderer, nullptr); + SDL_SetRenderClipRect(bd->SDLRenderer, nullptr); +} + +void ImGui_ImplSDLRenderer3_NewFrame() +{ + ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData(); + IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplSDLRenderer3_Init()?"); + + if (!bd->FontTexture) + ImGui_ImplSDLRenderer3_CreateDeviceObjects(); +} + +void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data) +{ + ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_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_GetRenderScale(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_RenderClipEnabled(bd->SDLRenderer) == SDL_TRUE; + SDL_GetRenderViewport(bd->SDLRenderer, &old.Viewport); + SDL_GetRenderClipRect(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_ImplSDLRenderer3_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_ImplSDLRenderer3_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_SetRenderClipRect(bd->SDLRenderer, &r); + + const float* xy = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, pos)); + const float* uv = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + 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) + offsetof(ImDrawVert, col)); // SDL 2.0.19+ +#else + const int* color = (const int*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + 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_SetRenderViewport(bd->SDLRenderer, &old.Viewport); + SDL_SetRenderClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : nullptr); +} + +// Called by Init/NewFrame/Shutdown +bool ImGui_ImplSDLRenderer3_CreateFontsTexture() +{ + ImGuiIO& io = ImGui::GetIO(); + ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_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_SCALEMODE_LINEAR); + + // Store our identifier + io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture); + + return true; +} + +void ImGui_ImplSDLRenderer3_DestroyFontsTexture() +{ + ImGuiIO& io = ImGui::GetIO(); + ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData(); + if (bd->FontTexture) + { + io.Fonts->SetTexID(0); + SDL_DestroyTexture(bd->FontTexture); + bd->FontTexture = nullptr; + } +} + +bool ImGui_ImplSDLRenderer3_CreateDeviceObjects() +{ + return ImGui_ImplSDLRenderer3_CreateFontsTexture(); +} + +void ImGui_ImplSDLRenderer3_DestroyDeviceObjects() +{ + ImGui_ImplSDLRenderer3_DestroyFontsTexture(); +} + +//----------------------------------------------------------------------------- + +#if defined(__clang__) +#pragma clang diagnostic pop +#endif + +#endif // #ifndef IMGUI_DISABLE |