Backends: SDL2, SDL3: don't call SDL_GetGlobalMouseState() when mouse position is in relative mode. (#8425, #8407)

backends/imgui_impl_sdl2.cpp

@@ -21,6 +21,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-02-24: Avoid calling SDL_GetGlobalMouseState() when mouse is in relative mode.
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
 //  2025-01-20: Made ImGui_ImplSDL2_SetGamepadMode(ImGui_ImplSDL2_GamepadMode_Manual) accept an empty array.
@@ -622,8 +623,10 @@ static void ImGui_ImplSDL2_UpdateMouseData()
             SDL_WarpMouseInWindow(bd->Window, (int)io.MousePos.x, (int)io.MousePos.y);
 
         // (Optional) Fallback to provide mouse position when focused (SDL_MOUSEMOTION already provides this when hovered or captured)
-        if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0)
+        const bool is_relative_mouse_mode = SDL_GetRelativeMouseMode() != 0;
+        if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0 && !is_relative_mouse_mode)
         {
+            // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
             int window_x, window_y, mouse_x_global, mouse_y_global;
             SDL_GetGlobalMouseState(&mouse_x_global, &mouse_y_global);
             SDL_GetWindowPosition(bd->Window, &window_x, &window_y);

backends/imgui_impl_sdl3.cpp

@@ -20,6 +20,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-02-24: Avoid calling SDL_GetGlobalMouseState() when mouse is in relative mode.
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
 //  2025-01-20: Made ImGui_ImplSDL3_SetGamepadMode(ImGui_ImplSDL3_GamepadMode_Manual) accept an empty array.
@@ -588,7 +589,8 @@ static void ImGui_ImplSDL3_UpdateMouseData()
             SDL_WarpMouseInWindow(bd->Window, io.MousePos.x, io.MousePos.y);
 
         // (Optional) Fallback to provide mouse position when focused (SDL_EVENT_MOUSE_MOTION already provides this when hovered or captured)
-        if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0)
+        const bool is_relative_mouse_mode = SDL_GetWindowRelativeMouseMode(bd->Window);
+        if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0 && !is_relative_mouse_mode)
         {
             // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
             float mouse_x_global, mouse_y_global;

docs/CHANGELOG.txt

@@ -87,10 +87,12 @@ Other changes:
   (busy/wait/hourglass shape, with or without an arrow cursor).
 - Demo: Combos: demonstrate a very simple way to add a filter to a combo,
   by showing the filter inside the combo contents. (#718)
-- Backends: SDL2, SDL3:  Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn
+- Backends: SDL2, SDL3: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn
   handler. (#7660) [@achabense]
 - Backends: SDL2, SDL3, Win32, Allegro5: Added support for ImGuiMouseCursor_Wait
   and ImGuiMouseCursor_Progress cursors.
+- Backends: SDL2, SDL3: Avoid calling SDL_GetGlobalMouseState() when mouse is in
+  relative mode. (#8425, #8407) [@TheMode]
 - Backends: OpenGL3: Lazily reinitialize embedded GL loader for when calling backend
   from e.g. other DLL boundaries. (#8406)
 - Backends: DirectX12: Fixed an issue where pre-1.91.5 legacy ImGui_ImplDX12_Init()