Implement Fl_Wayland_Screen_Driver::poll_or_select_with_delay(double)

documentation/src/wayland.dox

@@ -1056,10 +1056,7 @@ native platform window system. OpenGL-using FLTK apps are therefore linked to \c
 
 EGL is initialized calling member function \c Fl_Wayland_Gl_Window_Driver::init()
 once, the first time the \c Fl_Wayland_Gl_Window_Driver c'tor runs. That is done
-with calls to <tt>eglGetDisplay(), eglInitialize(), eglGetConfigs(), and
-eglBindAPI()</tt>. Function \c eglGetConfigs() computes the number of usable
-EGL frame buffer configurations for the display and stores it in static member variable
-\c Fl_Wayland_Gl_Window_Driver::configs_count.
+with calls to <tt>eglGetDisplay(), eglInitialize()</tt>, and \c eglBindAPI().
 
 Member function \c Fl_Wayland_Gl_Window_Driver::find() calls \c eglChooseConfig()
 to filter the set of GL configurations that match the \c Fl_Gl_Window's mode(),
@@ -1089,16 +1086,7 @@ FLTK function \c Fl_Gl_Window::make_current() calls overridden function
 FLTK calls function \c Fl_Wayland_Gl_Window_Driver::swap_buffers() each time it wants a
 GL context to be sent to the display. This function contains some pure GL code to
 emulate an overlay buffer to support Fl_Gl_Window objects overriding their
-\c draw_overlay() member function.
-Then, it calls function \c eglSwapBuffers() after having called
-\c wl_display_dispatch_pending() to synchronize EGL use
-with the rest of the Wayland compositor's activity.
-Function \c wl_display_dispatch_pending() calls the listeners attached to
-commands the Wayland compositor recently sent to the client.
-The fact that this function gets called during the process of drawing an Fl_Gl_Window
-makes possible a scenario that cannot occur with other FLTK platforms : a GL window can be
-closed while being drawn. Function \c Fl_Wayland_Window_Driver::hide() is written to
-handle such scenario without error (see comments therein).
+\c draw_overlay() member function. Then, it calls function \c eglSwapBuffers().
 
 The overridden \c Fl_Wayland_Gl_Window_Driver::resize() function is implemented with
 calls to \c wl_egl_window_get_attached_size() and \c wl_egl_window_resize().

src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.H

@@ -1,7 +1,7 @@
 //
 // Class Fl_Wayland_Gl_Window_Driver for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2021-2022 by Bill Spitzak and others.
+// Copyright 2021-2023 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -39,7 +39,6 @@ private:
   static EGLDisplay egl_display;
   struct wl_egl_window *egl_window;
   EGLSurface egl_surface;
-  bool egl_swap_in_progress;
   Fl_Wayland_Gl_Window_Driver(Fl_Gl_Window *win);
   float pixels_per_unit() FL_OVERRIDE;
   void make_current_before() FL_OVERRIDE;

src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx

@@ -69,7 +69,6 @@ Fl_Wayland_Gl_Window_Driver::Fl_Wayland_Gl_Window_Driver(Fl_Gl_Window *win) : Fl
   if (egl_display == EGL_NO_DISPLAY) init();
   egl_window = NULL;
   egl_surface = NULL;
-  egl_swap_in_progress = false;
 }
 
 
@@ -342,11 +341,8 @@ void Fl_Wayland_Gl_Window_Driver::swap_buffers() {
     if (!overlay_buffer) return; // don't call eglSwapBuffers until overlay has been drawn
   }
 
-  if (egl_surface && !egl_swap_in_progress) {
-    egl_swap_in_progress = true; // prevents crash while down resizing rotating glpuzzle
-    wl_display_dispatch_pending(Fl_Wayland_Screen_Driver::wl_display);
+  if (egl_surface) {
     eglSwapBuffers(Fl_Wayland_Gl_Window_Driver::egl_display, egl_surface);
-    egl_swap_in_progress = false;
   }
 }
 

src/drivers/Wayland/Fl_Wayland_Screen_Driver.H

@@ -168,6 +168,10 @@ public:
   int get_key(int k) FL_OVERRIDE;
   void enable_im() FL_OVERRIDE;
   void disable_im() FL_OVERRIDE;
+  
+  // overridden functions from parent class Fl_Unix_Screen_Driver
+  int poll_or_select_with_delay(double time_to_wait) FL_OVERRIDE;
+  int poll_or_select() FL_OVERRIDE;
 
 // Wayland-specific member functions
   void screen_count_set(int count) {num_screens = count;}

src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx

@@ -1681,6 +1681,21 @@ void *Fl_Wayland_Screen_Driver::control_maximize_button(void *data) {
 }
 
 
+int Fl_Wayland_Screen_Driver::poll_or_select_with_delay(double time_to_wait) {
+  wl_display_dispatch_pending(wl_display);
+  return Fl_Unix_Screen_Driver::poll_or_select_with_delay(time_to_wait);
+}
+
+
+// like Fl_Wayland_Screen_Driver::poll_or_select_with_delay(0.0) except no callbacks are done:
+int Fl_Wayland_Screen_Driver::poll_or_select() {
+  int ret = wl_display_prepare_read(wl_display);
+  if (ret == 0) wl_display_cancel_read(wl_display);
+  else return 1;
+  return Fl_Unix_Screen_Driver::poll_or_select();
+}
+
+
 int Fl_Wayland_Screen_Driver::event_key(int k) {
   if (k >= 'A' && k <= 'Z') k += 32;
   return (search_int_vector(key_vector, k) >= 0);

src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx

@@ -427,12 +427,6 @@ static void destroy_surface_caution_pointer_focus(struct wl_surface *surface,
 }
 
 
-static void delayed_delete_Fl_X(void *data) {
-  Fl::remove_check(delayed_delete_Fl_X, data);
-  delete (Fl_X*)data;
-}
-
-
 void Fl_Wayland_Window_Driver::hide() {
   Fl_X* ip = Fl_X::flx(pWindow);
   if (hide_common()) return;
@@ -483,22 +477,7 @@ void Fl_Wayland_Window_Driver::hide() {
 //fprintf(stderr, "After hide: sub=%p frame=%p xdg=%p top=%p pop=%p surf=%p\n", wld_win->subsurface,  wld_win->frame, wld_win->xdg_surface, wld_win->xdg_toplevel, wld_win->xdg_popup, wld_win->wl_surface);
     free(wld_win);
   }
-  if (pWindow->as_gl_window() && in_flush_) {
-    // Under Wayland and for a GL window, this summarized scenario can occur
-    // when closing a window with "escape" (e.g. test/cube):
-    // Fl::flush() calls Fl_Wayland_Window_Driver::flush()
-    // calls Fl_Wayland_Gl_Window_Driver::swap_buffers()
-    // calls wl_display_dispatch_pending() calls Fl_Wayland_Window_Driver::hide().
-    // We make sure here to force exit from the loop over all damaged windows
-    // in Fl::flush(), and postpone deletion of the Fl_X record until after return
-    // from Fl::flush().
-      ip->xid = 0;
-      ip->next = NULL;
-      Fl::damage(1); // make sure potential remaining damaged windows get drawn
-      Fl::add_check(delayed_delete_Fl_X, ip);
-    } else {
-      delete ip;
-    }
+  delete ip;
 }