Backends: SDL: Wayland: Use SDL_GetMouseState (amend 78ff147) (#2800, 2802)

docs/CHANGELOG.txt

@@ -71,6 +71,8 @@ Other Changes:
   selection, those new api can fill a gap. [@ShironekoBen]
 - Backends: GLFW, SDL, Win32, OSX, Allegro: Added support for ImGuiMouseCursor_NotAllowed. [@rokups]
 - Backends: GLFW: Added support for the missing mouse cursors newly added in GLFW 3.4+. [@rokups]
+- Backends: SDL: Wayland: use SDL_GetMouseState (because there is no global mouse state available
+  on Wayland). (#2800, #2802) [@NeroBurner]
 - Examples: Explicitly adding -DIMGUI_IMPL_OPENGL_LOADER_GL3W to Makefile to match linking
   settings (otherwise if another loader such as Glew is accessible, the opengl3 backend might
   automatically use it). [#2919, #2798]

examples/imgui_impl_sdl.cpp

@@ -17,7 +17,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2019-12-17: Inputs: Use SDL_GetMouseState, because there is no global mouse state on Wayland.
+//  2019-12-17: Inputs: On Wayland, use SDL_GetMouseState (because there is no global mouse state).
 //  2019-12-05: Inputs: Added support for ImGuiMouseCursor_NotAllowed mouse cursor.
 //  2019-07-21: Inputs: Added mapping for ImGuiKey_KeyPadEnter.
 //  2019-04-23: Inputs: Added support for SDL_GameController (if ImGuiConfigFlags_NavEnableGamepad is set by user application).
@@ -61,7 +61,7 @@ static Uint64       g_Time = 0;
 static bool         g_MousePressed[3] = { false, false, false };
 static SDL_Cursor*  g_MouseCursors[ImGuiMouseCursor_COUNT] = {};
 static char*        g_ClipboardTextData = NULL;
-static bool         g_VideoDriverIsWayland = false;
+static bool         g_MouseCanUseGlobalState = true;
 
 static const char* ImGui_ImplSDL2_GetClipboardText(void*)
 {
@@ -126,9 +126,6 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
 {
     g_Window = window;
 
-    // Check and store if we are on Wayland to not check on every frame.
-    g_VideoDriverIsWayland = strncmp(SDL_GetCurrentVideoDriver(), "wayland", 7) == 0;
-
     // Setup back-end capabilities flags
     ImGuiIO& io = ImGui::GetIO();
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;       // We can honor GetMouseCursor() values (optional)
@@ -163,6 +160,7 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     io.GetClipboardTextFn = ImGui_ImplSDL2_GetClipboardText;
     io.ClipboardUserData = NULL;
 
+    // Load mouse cursors
     g_MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
     g_MouseCursors[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_IBEAM);
     g_MouseCursors[ImGuiMouseCursor_ResizeAll] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEALL);
@@ -173,6 +171,9 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window)
     g_MouseCursors[ImGuiMouseCursor_Hand] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
     g_MouseCursors[ImGuiMouseCursor_NotAllowed] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NO);
 
+    // Check and store if we are on Wayland
+    g_MouseCanUseGlobalState = strncmp(SDL_GetCurrentVideoDriver(), "wayland", 7) != 0;
+
 #ifdef _WIN32
     SDL_SysWMinfo wmInfo;
     SDL_VERSION(&wmInfo.version);
@@ -243,7 +244,7 @@ static void ImGui_ImplSDL2_UpdateMousePosAndButtons()
     SDL_Window* focused_window = SDL_GetKeyboardFocus();
     if (g_Window == focused_window)
     {
-        if (!g_VideoDriverIsWayland)
+        if (g_MouseCanUseGlobalState)
         {
             // SDL_GetMouseState() gives mouse position seemingly based on the last window entered/focused(?)
             // The creation of a new windows at runtime and SDL_CaptureMouse both seems to severely mess up with that, so we retrieve that position globally.