wayland: Avoid busy waiting for vsync

This commit is contained in:
Cameron Gutman 2021-08-08 16:47:34 -05:00 committed by Sam Lantinga
parent 791d9d3ff6
commit 092a20d945
1 changed files with 19 additions and 5 deletions

View File

@ -130,14 +130,28 @@ Wayland_GLES_SwapWindow(_THIS, SDL_Window *window)
struct wl_display *display = ((SDL_VideoData *)_this->driverdata)->display;
SDL_VideoDisplay *sdldisplay = SDL_GetDisplayForWindow(window);
const Uint32 max_wait = SDL_GetTicks() + (10000 / sdldisplay->current_mode.refresh_rate); /* ~10 frames, so we'll progress even if throttled to zero. */
while ((SDL_AtomicGet(&data->swap_interval_ready) == 0) && (!SDL_TICKS_PASSED(SDL_GetTicks(), max_wait))) {
while (SDL_AtomicGet(&data->swap_interval_ready) == 0) {
Uint32 now;
/* !!! FIXME: this is just the crucial piece of Wayland_PumpEvents */
WAYLAND_wl_display_flush(display);
if (SDL_IOReady(WAYLAND_wl_display_get_fd(display), SDL_FALSE, 0)) {
WAYLAND_wl_display_dispatch(display);
} else {
WAYLAND_wl_display_dispatch_pending(display);
if (WAYLAND_wl_display_dispatch_pending(display) > 0) {
/* We dispatched some pending events. Check if the frame callback happened. */
continue;
}
now = SDL_GetTicks();
if (SDL_TICKS_PASSED(now, max_wait)) {
/* Timeout expired */
break;
}
if (SDL_IOReady(WAYLAND_wl_display_get_fd(display), SDL_FALSE, max_wait - now) <= 0) {
/* Error or timeout expired without any events for us */
break;
}
WAYLAND_wl_display_dispatch(display);
}
SDL_AtomicSet(&data->swap_interval_ready, 0);
}