Robert, I would like to know more on the allocate/paint process of the clutter-actor, could you please provide more detail on that? So if I apply the scenegraph optimization, I will hook into those function, is that correct?
Thanks, -Hieu -----Original Message----- From: clutter-app-devel-list-boun...@clutter-project.org [mailto:clutter-app-devel-list-boun...@clutter-project.org] On Behalf Of Robert Bragg Sent: Thursday, January 13, 2011 8:34 PM To: James Moschou Cc: clutter-app-devel-list Subject: Re: Optimise painting of stage Hi James, It could be worth you trying Clutter master if you aren't already, to see if your application can take advantage of the automatic clipped-redraws and culling optimizations that landed during this development cycle. The clipped-redraws optimization aims to automatically determine the bounding box of the actors that have changed while preparing to draw the next frame so that, for example, if you have only moused over a button which has changed its highlight then the bounding box just covers that button and when we come to redraw we actually scissor all rendering to that button so we wont touch any pixels outside that box. Previous versions of clutter would instead have to redraw the entire stage. The second optimization is applied when we are traversing the scenegraph. It takes the clip-box determined by the above optimization and then for each actor it starts by checking if the actor intersects the current clip-box if it doesn't then further processing of that actor is immediately skipped. So with just the clipped-redraws optimization we know we won't draw any pixels outside the clip-box of around the button, but we are still relying on the GPU to do quite a lot of work potentially to cull all the geometry outside that region. With the culling optimization we avoid even sending geometry to the GPU and can also avoid lots of application logic associated with painting actors outside the current clip-box. To take advantage of these optimizations your actors need to implement the get_paint_volume vfunc. The actors from Clutter already implement this but most of the default implementations will be disabled if the actor is sub-classed, because we can't make any assumptions about what was changed in the sub-class. There is a visual debugging aid available if you export CLUTTER_PAINT=redraws or CLUTTER_PAINT=paint-volumes before running you application which can show what parts of the stage are being redrawn. There probably needs to more documentation about this stuff, so if you have any issues with getting clipped-redraws/culling to work with your application please ask for more details, and we'll try our best to help. kind regards, - Robert Excerpts from James Moschou's message of Mon Jan 10 15:03:05 +0000 2011: > Hi, > > Is there anyway to capture the paint 'output' of an actor plus child > actors, and store it in a texture? The purpose being to simply repaint > that texture as an optimisation, instead of painting each individual > child actor. > > My situation is that I have two 'scrollviews' as it were, the classic > set up of a sidepane on the left with expandable items, and a main > content view in the right pane. Each sidepane item actor has child > actors for the label, icon and expander, so even just considering the > ones actually visible there are still a lot of actors. The lag happens > when you scroll the content view, since it has to repaint the entire > stage for every motion event, including the sidepane items > unnecessarily. Really I should be able to cache this portion of the > stage, since it doesn't change when the content view is being > scrolled. > > Also capturing the output of an actor would further improve the > scrollview's in that I could shift the texture across, and only paint > the newly revealed portion. > > Thanks, > James -- Robert Bragg, Intel Open Source Technology Center _______________________________________________ clutter-app-devel-list mailing list clutter-app-devel-list@clutter-project.org http://lists.clutter-project.org/listinfo/clutter-app-devel-list _______________________________________________ clutter-app-devel-list mailing list clutter-app-devel-list@clutter-project.org http://lists.clutter-project.org/listinfo/clutter-app-devel-list
