wayland: Add a property to allow creation of a wl_egl_window object even if OpenGL is not enabled

Useful if the application handles OpenGL outside of SDL and wants to use the window without having to pull in Wayland as a dependency.

include/SDL3/SDL_video.h

@@ -872,6 +872,9 @@ extern DECLSPEC SDL_Window *SDLCALL SDL_CreatePopupWindow(SDL_Window *parent, in
  *   if the application wants to use the Wayland surface for a custom role and
  *   does not want it attached to an XDG toplevel window. See
  *   docs/README-wayland.md for more information on using custom surfaces.
+ * - `SDL_PROPERTY_WINDOW_CREATE_WAYLAND_CREATE_EGL_WINDOW_BOOLEAN - true if
+ *   the application wants an associated `wl_egl_window` object to be created,
+ *   even if the window does not have the OpenGL property or flag set.
  *
  * These are additional supported properties on Windows:
  *
@@ -927,6 +930,7 @@ extern DECLSPEC SDL_Window *SDLCALL SDL_CreateWindowWithProperties(SDL_Propertie
 #define SDL_PROPERTY_WINDOW_CREATE_COCOA_WINDOW_POINTER                "cocoa.window"
 #define SDL_PROPERTY_WINDOW_CREATE_COCOA_VIEW_POINTER                  "cocoa.view"
 #define SDL_PROPERTY_WINDOW_CREATE_WAYLAND_SURFACE_ROLE_CUSTOM_BOOLEAN "wayland.surface_role_custom"
+#define SDL_PROPERTY_WINDOW_CREATE_WAYLAND_CREATE_EGL_WINDOW_BOOLEAN   "wayland.create_egl_window"
 #define SDL_PROPERTY_WINDOW_CREATE_WIN32_HWND_POINTER                  "win32.hwnd"
 #define SDL_PROPERTY_WINDOW_CREATE_WIN32_PIXEL_FORMAT_HWND_POINTER     "win32.pixel_format_hwnd"
 #define SDL_PROPERTY_WINDOW_CREATE_X11_WINDOW_NUMBER                   "x11.window"

src/video/wayland/SDL_waylandwindow.c

@@ -2056,6 +2056,8 @@ int Wayland_CreateWindow(SDL_VideoDevice *_this, SDL_Window *window, SDL_Propert
     SDL_WindowData *data;
     SDL_VideoData *c;
     const SDL_bool custom_surface_role = SDL_GetBooleanProperty(create_props, SDL_PROPERTY_WINDOW_CREATE_WAYLAND_SURFACE_ROLE_CUSTOM_BOOLEAN, SDL_FALSE);
+    const SDL_bool create_egl_window = !!(window->flags & SDL_WINDOW_OPENGL) ||
+                                       SDL_GetBooleanProperty(create_props, SDL_PROPERTY_WINDOW_CREATE_WAYLAND_CREATE_EGL_WINDOW_BOOLEAN, SDL_FALSE);
 
     data = SDL_calloc(1, sizeof(*data));
     if (!data) {
@@ -2129,18 +2131,20 @@ int Wayland_CreateWindow(SDL_VideoDevice *_this, SDL_Window *window, SDL_Propert
         }
     }
 
-    if (window->flags & SDL_WINDOW_OPENGL) {
+    if (create_egl_window) {
         data->egl_window = WAYLAND_wl_egl_window_create(data->surface, data->drawable_width, data->drawable_height);
+    }
 
 #ifdef SDL_VIDEO_OPENGL_EGL
+    if (window->flags & SDL_WINDOW_OPENGL) {
         /* Create the GLES window surface */
         data->egl_surface = SDL_EGL_CreateSurface(_this, window, (NativeWindowType)data->egl_window);
 
         if (data->egl_surface == EGL_NO_SURFACE) {
             return -1; /* SDL_EGL_CreateSurface should have set error */
         }
-#endif
     }
+#endif
 
     if (c->relative_mouse_mode) {
         Wayland_input_lock_pointer(c->input);