From b34034217abb9227219d8408b8bdcae0a840e96b Mon Sep 17 00:00:00 2001 From: Neil Roberts Date: Thu, 31 Jan 2013 16:53:16 +0000 Subject: [PATCH] Make it possible to call swap_buffers within a frame event callback It seems like it would be quite a reasonable design for an application to immediately paint the buffer and call swap_buffers within the handler for the sync event. This previously wouldn't work. When using the GLX winsys if swap_region is called then it immediately tries to set the pending notification flag. However if this is called from the event callback then when the callback is complete it will clear the flag again and the pending notification will be lost. This patch just makes it clear the pending flag before invoking the callback so that it can be safely queued again. With any winsys that doesn't directly handle the sync event notification it would almost work except that it was iterating the live list of pending events. If the callback causes another event to be added to this list by issuing a buffer swap then the iteration would never complete and cogl_poll_dispatch would never return. This patch just makes it steal the list before iterating so that any additions will be dispatched by a later call to cogl_poll_dispatch instead. Reviewed-by: Robert Bragg (cherry picked from commit 2263b31594900b73900d2ce22cf70c68e7e793c6) --- cogl/cogl-onscreen.c | 14 +++++++++++--- cogl/winsys/cogl-winsys-glx.c | 23 ++++++++++++++++------- 2 files changed, 27 insertions(+), 10 deletions(-) diff --git a/cogl/cogl-onscreen.c b/cogl/cogl-onscreen.c index 5f72454e6..23f62bac0 100644 --- a/cogl/cogl-onscreen.c +++ b/cogl/cogl-onscreen.c @@ -3,7 +3,7 @@ * * An object oriented GL/GLES Abstraction/Utility Layer * - * Copyright (C) 2011 Intel Corporation. + * Copyright (C) 2011, 2013 Intel Corporation. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -524,9 +524,18 @@ void _cogl_dispatch_onscreen_events (CoglContext *context) { CoglOnscreenEvent *event, *tmp; + CoglOnscreenEventList queue; + + /* Dispatching the event callback may cause another frame to be + * drawn which in may cause another event to be queued immediately. + * To make sure this loop will only dispatch one set of events we'll + * steal the queue and iterate that separately */ + COGL_TAILQ_INIT (&queue); + COGL_TAILQ_CONCAT (&queue, &context->onscreen_events_queue, list_node); + COGL_TAILQ_INIT (&context->onscreen_events_queue); COGL_TAILQ_FOREACH_SAFE (event, - &context->onscreen_events_queue, + &queue, list_node, tmp) { @@ -538,7 +547,6 @@ _cogl_dispatch_onscreen_events (CoglContext *context) cogl_object_unref (onscreen); cogl_object_unref (info); - COGL_TAILQ_REMOVE (&context->onscreen_events_queue, event, list_node); g_slice_free (CoglOnscreenEvent, event); } } diff --git a/cogl/winsys/cogl-winsys-glx.c b/cogl/winsys/cogl-winsys-glx.c index 10228cc3b..a58a6ce1b 100644 --- a/cogl/winsys/cogl-winsys-glx.c +++ b/cogl/winsys/cogl-winsys-glx.c @@ -2542,21 +2542,27 @@ flush_pending_notifications_cb (void *data, { CoglOnscreen *onscreen = COGL_ONSCREEN (framebuffer); CoglOnscreenGLX *glx_onscreen = onscreen->winsys; + CoglBool pending_sync_notify = glx_onscreen->pending_sync_notify; + CoglBool pending_complete_notify = glx_onscreen->pending_complete_notify; - if (glx_onscreen->pending_sync_notify) + /* If swap_region is called then notifying the sync event could + * potentially immediately queue a subsequent pending notify so + * we need to clear the flag before invoking the callback */ + glx_onscreen->pending_sync_notify = FALSE; + glx_onscreen->pending_complete_notify = FALSE; + + if (pending_sync_notify) { CoglFrameInfo *info = g_queue_peek_head (&onscreen->pending_frame_infos); _cogl_onscreen_notify_frame_sync (onscreen, info); - glx_onscreen->pending_sync_notify = FALSE; } - if (glx_onscreen->pending_complete_notify) + if (pending_complete_notify) { CoglFrameInfo *info = g_queue_pop_head (&onscreen->pending_frame_infos); _cogl_onscreen_notify_complete (onscreen, info); - glx_onscreen->pending_complete_notify = FALSE; cogl_object_unref (info); } @@ -2585,12 +2591,15 @@ _cogl_winsys_poll_dispatch (CoglContext *context, glx_display->pending_resize_notify || glx_display->pending_complete_notify) { - g_list_foreach (context->framebuffers, - flush_pending_notifications_cb, - NULL); + /* These need to be cleared before invoking the callbacks in + * case the callbacks cause them to be set again */ glx_display->pending_sync_notify = FALSE; glx_display->pending_resize_notify = FALSE; glx_display->pending_complete_notify = FALSE; + + g_list_foreach (context->framebuffers, + flush_pending_notifications_cb, + NULL); } }