From bca39776d3080c180cdcf6698a54ee2c25bb5383 Mon Sep 17 00:00:00 2001 From: Robert Bragg Date: Fri, 21 Jan 2011 19:05:23 +0000 Subject: [PATCH] framebuffer: flush journal when switching framebuffers There is currently a problem with per-framebuffer journals in that it's possible to create a framebuffer from a texture which then gets rendered too but the framebuffer (and corresponding journal) can be freed before the texture gets used to draw with. Conceptually we want to make sure when freeing a framebuffer that - if it is associated with a texture - we flush the journal as the last thing before really freeing the framebuffer's meta data. Technically though this is awkward to implement since the obvious mechanism for us to be notified about the framebuffer's destruction (by setting some user data internally with a callback) notifies when the framebuffer has a ref-count of 0. This means we'd have to be careful what we do with the framebuffer to consider e.g. recursive destruction; anything that would set more user data on the framebuffer while it is being destroyed and ensuring nothing else gets notified of the framebuffer's destruction before the journal has been flushed. For simplicity, for now, this patch provides another solution which is to flush framebuffer journals whenever we switch away from a given framebuffer via cogl_set_framebuffer or cogl_push/pop_framebuffer. The disadvantage of this approach is that we can't batch all the geometry of a scene that involves intermediate renders to offscreen framebufers. Clutter is doing this more and more with applications that use the ClutterEffect APIs so this is a shame. Hopefully this will only be a stop-gap solution while we consider how to reliably support journal logging across framebuffer changes. --- clutter/cogl/cogl/cogl-framebuffer.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/clutter/cogl/cogl/cogl-framebuffer.c b/clutter/cogl/cogl/cogl-framebuffer.c index f14b80b..a788dd5 100644 --- a/clutter/cogl/cogl/cogl-framebuffer.c +++ b/clutter/cogl/cogl/cogl-framebuffer.c @@ -587,7 +587,8 @@ _cogl_framebuffer_remove_all_dependencies (CoglFramebuffer *framebuffer) void _cogl_framebuffer_flush_journal (CoglFramebuffer *framebuffer) { - _cogl_journal_flush (framebuffer->journal, framebuffer); + if (framebuffer) + _cogl_journal_flush (framebuffer->journal, framebuffer); } void @@ -1045,10 +1046,20 @@ _cogl_set_framebuffer_real (CoglFramebuffer *framebuffer) void cogl_set_framebuffer (CoglFramebuffer *framebuffer) { + CoglFramebuffer *current; + g_return_if_fail (_cogl_is_framebuffer (framebuffer)); - if (_cogl_get_framebuffer () != framebuffer) - _cogl_set_framebuffer_real (framebuffer); + current = _cogl_get_framebuffer (); + if (current != framebuffer) + { + /* XXX: eventually we want to remove this implicit journal flush + * so we can log into the journal beyond framebuffer changes to + * support batching scenes that depend on the results of + * mid-scene renders to textures. */ + _cogl_framebuffer_flush_journal (current); + _cogl_set_framebuffer_real (framebuffer); + } } /* XXX: deprecated API */ @@ -1108,7 +1119,14 @@ cogl_pop_framebuffer (void) to_pop = ctx->framebuffer_stack->data; to_restore = ctx->framebuffer_stack->next->data; - cogl_flush (); + if (to_pop != to_restore) + { + /* XXX: eventually we want to remove this implicit journal flush + * so we can log into the journal beyond framebuffer changes to + * support batching scenes that depend on the results of + * mid-scene renders to textures. */ + _cogl_framebuffer_flush_journal (to_pop); + } cogl_object_unref (to_pop); ctx->framebuffer_stack = -- 2.7.4