Backends: SDL_Renderer2/SDL_Renderer3: and ImGui_ImplSDLRenderer2_RenderDrawData() and ImGui_ImplSDLRenderer3_RenderDrawData() now takes a SDL_Renderer* parameter.

backends/imgui_impl_sdlrenderer2.cpp

@@ -20,6 +20,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
+//  2024-05-14: *BREAKING CHANGE* ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
 //  2023-05-30: Renamed imgui_impl_sdlrenderer.h/.cpp to imgui_impl_sdlrenderer2.h/.cpp to accommodate for upcoming SDL3.
 //  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.
@@ -47,9 +48,9 @@
 // SDL_Renderer data
 struct ImGui_ImplSDLRenderer2_Data
 {
-    SDL_Renderer*   SDLRenderer;
+    SDL_Renderer*   Renderer;       // Main viewport's renderer
     SDL_Texture*    FontTexture;
-    ImGui_ImplSDLRenderer2_Data() { memset((void*)this, 0, sizeof(*this)); }
+    ImGui_ImplSDLRenderer2_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
 
 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
@@ -73,7 +74,7 @@ bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
     io.BackendRendererName = "imgui_impl_sdlrenderer2";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
-    bd->SDLRenderer = renderer;
+    bd->Renderer = renderer;
 
     return true;
 }
@@ -92,14 +93,12 @@ void ImGui_ImplSDLRenderer2_Shutdown()
     IM_DELETE(bd);
 }
 
-static void ImGui_ImplSDLRenderer2_SetupRenderState()
+static void ImGui_ImplSDLRenderer2_SetupRenderState(SDL_Renderer* renderer)
 {
-	ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_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);
+	SDL_RenderSetViewport(renderer, nullptr);
+	SDL_RenderSetClipRect(renderer, nullptr);
 }
 
 void ImGui_ImplSDLRenderer2_NewFrame()
@@ -111,16 +110,14 @@ void ImGui_ImplSDLRenderer2_NewFrame()
         ImGui_ImplSDLRenderer2_CreateDeviceObjects();
 }
 
-void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
+void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
 {
-	ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_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);
+	SDL_RenderGetScale(renderer, &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;
@@ -139,16 +136,16 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
         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);
+    old.ClipEnabled = SDL_RenderIsClipEnabled(renderer) == SDL_TRUE;
+    SDL_RenderGetViewport(renderer, &old.Viewport);
+    SDL_RenderGetClipRect(renderer, &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_ImplSDLRenderer2_SetupRenderState();
+    ImGui_ImplSDLRenderer2_SetupRenderState(renderer);
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
@@ -163,7 +160,7 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
                 // 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_ImplSDLRenderer2_SetupRenderState();
+                    ImGui_ImplSDLRenderer2_SetupRenderState(renderer);
                 else
                     pcmd->UserCallback(cmd_list, pcmd);
             }
@@ -180,7 +177,7 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
                     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);
+                SDL_RenderSetClipRect(renderer, &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));
@@ -192,7 +189,7 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
 
                 // Bind texture, Draw
 				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
-                SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
+                SDL_RenderGeometryRaw(renderer, tex,
                     xy, (int)sizeof(ImDrawVert),
                     color, (int)sizeof(ImDrawVert),
                     uv, (int)sizeof(ImDrawVert),
@@ -203,8 +200,8 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
     }
 
     // Restore modified SDL_Renderer state
-    SDL_RenderSetViewport(bd->SDLRenderer, &old.Viewport);
-    SDL_RenderSetClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : nullptr);
+    SDL_RenderSetViewport(renderer, &old.Viewport);
+    SDL_RenderSetClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }
 
 // Called by Init/NewFrame/Shutdown
@@ -220,7 +217,7 @@ bool ImGui_ImplSDLRenderer2_CreateFontsTexture()
 
     // 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);
+    bd->FontTexture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
     if (bd->FontTexture == nullptr)
     {
         SDL_Log("error creating texture");

backends/imgui_impl_sdlrenderer2.h

@@ -28,7 +28,7 @@ struct SDL_Renderer;
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer);
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_NewFrame();
-IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data);
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer);
 
 // Called by Init/NewFrame/Shutdown
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer2_CreateFontsTexture();

backends/imgui_impl_sdlrenderer3.cpp

@@ -20,6 +20,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
+//  2024-05-14: *BREAKING CHANGE* ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
 //  2024-02-12: Amend to query SDL_RenderViewportSet() and restore viewport accordingly.
 //  2023-05-30: Initial version.
 
@@ -43,9 +44,9 @@
 // SDL_Renderer data
 struct ImGui_ImplSDLRenderer3_Data
 {
-    SDL_Renderer*   SDLRenderer;
+    SDL_Renderer*   Renderer;       // Main viewport's renderer
     SDL_Texture*    FontTexture;
-    ImGui_ImplSDLRenderer3_Data() { memset((void*)this, 0, sizeof(*this)); }
+    ImGui_ImplSDLRenderer3_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
 
 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
@@ -69,7 +70,7 @@ bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
     io.BackendRendererName = "imgui_impl_sdlrenderer3";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
-    bd->SDLRenderer = renderer;
+    bd->Renderer = renderer;
 
     return true;
 }
@@ -88,14 +89,12 @@ void ImGui_ImplSDLRenderer3_Shutdown()
     IM_DELETE(bd);
 }
 
-static void ImGui_ImplSDLRenderer3_SetupRenderState()
+static void ImGui_ImplSDLRenderer3_SetupRenderState(SDL_Renderer* renderer)
 {
-	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);
+	SDL_SetRenderViewport(renderer, nullptr);
+	SDL_SetRenderClipRect(renderer, nullptr);
 }
 
 void ImGui_ImplSDLRenderer3_NewFrame()
@@ -107,16 +106,14 @@ void ImGui_ImplSDLRenderer3_NewFrame()
         ImGui_ImplSDLRenderer3_CreateDeviceObjects();
 }
 
-void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
+void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
 {
-	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);
+	SDL_GetRenderScale(renderer, &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;
@@ -136,17 +133,17 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
         SDL_Rect    ClipRect;
     };
     BackupSDLRendererState old = {};
-    old.ViewportEnabled = SDL_RenderViewportSet(bd->SDLRenderer) == SDL_TRUE;
-    old.ClipEnabled = SDL_RenderClipEnabled(bd->SDLRenderer) == SDL_TRUE;
-    SDL_GetRenderViewport(bd->SDLRenderer, &old.Viewport);
-    SDL_GetRenderClipRect(bd->SDLRenderer, &old.ClipRect);
+    old.ViewportEnabled = SDL_RenderViewportSet(renderer) == SDL_TRUE;
+    old.ClipEnabled = SDL_RenderClipEnabled(renderer) == SDL_TRUE;
+    SDL_GetRenderViewport(renderer, &old.Viewport);
+    SDL_GetRenderClipRect(renderer, &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();
+    ImGui_ImplSDLRenderer3_SetupRenderState(renderer);
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
@@ -161,7 +158,7 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
                 // 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();
+                    ImGui_ImplSDLRenderer3_SetupRenderState(renderer);
                 else
                     pcmd->UserCallback(cmd_list, pcmd);
             }
@@ -178,7 +175,7 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
                     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);
+                SDL_SetRenderClipRect(renderer, &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));
@@ -186,7 +183,7 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
 
                 // Bind texture, Draw
 				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
-                SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
+                SDL_RenderGeometryRaw(renderer, tex,
                     xy, (int)sizeof(ImDrawVert),
                     color, (int)sizeof(ImDrawVert),
                     uv, (int)sizeof(ImDrawVert),
@@ -197,8 +194,8 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
     }
 
     // Restore modified SDL_Renderer state
-    SDL_SetRenderViewport(bd->SDLRenderer, old.ViewportEnabled ? &old.Viewport : nullptr);
-    SDL_SetRenderClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : nullptr);
+    SDL_SetRenderViewport(renderer, old.ViewportEnabled ? &old.Viewport : nullptr);
+    SDL_SetRenderClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }
 
 // Called by Init/NewFrame/Shutdown
@@ -214,7 +211,7 @@ bool ImGui_ImplSDLRenderer3_CreateFontsTexture()
 
     // 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);
+    bd->FontTexture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
     if (bd->FontTexture == nullptr)
     {
         SDL_Log("error creating texture");

backends/imgui_impl_sdlrenderer3.h

@@ -28,7 +28,7 @@ struct SDL_Renderer;
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer);
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_NewFrame();
-IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data);
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer);
 
 // Called by Init/NewFrame/Shutdown
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer3_CreateFontsTexture();

docs/CHANGELOG.txt

@@ -41,6 +41,10 @@ HOW TO UPDATE?
 
 Breaking changes:
 
+- Backends: SDL_Renderer2/SDL_Renderer3: and ImGui_ImplSDLRenderer2_RenderDrawData() and
+  ImGui_ImplSDLRenderer3_RenderDrawData() now takes a SDL_Renderer* parameter. This was previously
+  overlooked from the API but it will facilitate eventual support for multi-viewports.
+
 Other changes:
 
 - Nav: fixed holding Ctrl or gamepad L1 from not slowing down keyboard/gamepad tweak speed.

examples/example_sdl2_sdlrenderer2/main.cpp

@@ -155,7 +155,7 @@ int main(int, char**)
         SDL_RenderSetScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
         SDL_SetRenderDrawColor(renderer, (Uint8)(clear_color.x * 255), (Uint8)(clear_color.y * 255), (Uint8)(clear_color.z * 255), (Uint8)(clear_color.w * 255));
         SDL_RenderClear(renderer);
-        ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData());
+        ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData(), renderer);
         SDL_RenderPresent(renderer);
     }
 

examples/example_sdl3_sdlrenderer3/main.cpp

@@ -161,7 +161,7 @@ int main(int, char**)
         //SDL_RenderSetScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
         SDL_SetRenderDrawColor(renderer, (Uint8)(clear_color.x * 255), (Uint8)(clear_color.y * 255), (Uint8)(clear_color.z * 255), (Uint8)(clear_color.w * 255));
         SDL_RenderClear(renderer);
-        ImGui_ImplSDLRenderer3_RenderDrawData(ImGui::GetDrawData());
+        ImGui_ImplSDLRenderer3_RenderDrawData(ImGui::GetDrawData(), renderer);
         SDL_RenderPresent(renderer);
     }
 

imgui.cpp

@@ -430,6 +430,7 @@ CODE
  When you are not sure about an old symbol or function name, try using the Search/Find function of your IDE to look for comments or references in all imgui files.
  You can read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2024/05/14 (1.90.7) - backends: SDL_Renderer2 and SDL_Renderer3 backend now take a SDL_Renderer* in their RenderDrawData() functions.
  - 2024/04/18 (1.90.6) - TreeNode: Fixed a layout inconsistency when using an empty/hidden label followed by a SameLine() call. (#7505, #282)
                            - old: TreeNode("##Hidden"); SameLine(); Text("Hello");     // <-- This was actually incorrect! BUT appeared to look ok with the default style where ItemSpacing.x == FramePadding.x * 2 (it didn't look aligned otherwise).
                            - new: TreeNode("##Hidden"); SameLine(0, 0); Text("Hello"); // <-- This is correct for all styles values.