ui/gtk: Make sure the right EGL context is currently bound

Observed a wrong context is bound when changing the scanout mode.
To prevent problem, it is needed to make sure to bind the right
context in gtk_egl_set_scanout_mode/gtk_gl_area_set_scanout_mode
as well as unbind one in the end of gd_egl_update/gd_gl_area_update.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20230628191504.17185-1-dongwon.kim@intel.com>

ui/gtk-egl.c

@@ -32,6 +32,8 @@ static void gtk_egl_set_scanout_mode(VirtualConsole *vc, bool scanout)
 
     vc->gfx.scanout_mode = scanout;
     if (!vc->gfx.scanout_mode) {
+        eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                       vc->gfx.esurface, vc->gfx.ectx);
         egl_fb_destroy(&vc->gfx.guest_fb);
         if (vc->gfx.surface) {
             surface_gl_destroy_texture(vc->gfx.gls, vc->gfx.ds);
@@ -135,6 +137,8 @@ void gd_egl_update(DisplayChangeListener *dcl,
                    vc->gfx.esurface, vc->gfx.ectx);
     surface_gl_update_texture(vc->gfx.gls, vc->gfx.ds, x, y, w, h);
     vc->gfx.glupdates++;
+    eglMakeCurrent(qemu_egl_display, EGL_NO_SURFACE,
+                   EGL_NO_SURFACE, EGL_NO_CONTEXT);
 }
 
 void gd_egl_refresh(DisplayChangeListener *dcl)

ui/gtk-gl-area.c

@@ -26,6 +26,7 @@ static void gtk_gl_area_set_scanout_mode(VirtualConsole *vc, bool scanout)
 
     vc->gfx.scanout_mode = scanout;
     if (!vc->gfx.scanout_mode) {
+        gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
         egl_fb_destroy(&vc->gfx.guest_fb);
         if (vc->gfx.surface) {
             surface_gl_destroy_texture(vc->gfx.gls, vc->gfx.ds);
@@ -115,6 +116,7 @@ void gd_gl_area_update(DisplayChangeListener *dcl,
     gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
     surface_gl_update_texture(vc->gfx.gls, vc->gfx.ds, x, y, w, h);
     vc->gfx.glupdates++;
+    gdk_gl_context_clear_current();
 }
 
 void gd_gl_area_refresh(DisplayChangeListener *dcl)