Re: OpenGL Vertical Syncing effect on run loops
Re: OpenGL Vertical Syncing effect on run loops
- Subject: Re: OpenGL Vertical Syncing effect on run loops
- From: Jerry Krinock <email@hidden>
- Date: Sat, 26 Sep 2015 06:24:35 -0700
On 2015 Sep 22, at 19:51, Greg Parker <email@hidden> wrote:
> But at some point the timer callback will provoke an OpenGL buffer swap, and that will block until the next retrace when vertical synchronization is enabled. The gated buffer swap inside the timer callback is the rate-limiting factor, not anything in the runloop or NSTimer itself.
Thank you, Greg. I’ve done some testing on this but still don’t understand how this buffer swap blocks the timer. The only thing in the timer callback is -setNeedsDisplay:, and that seems to return in microseconds. But it’s no big deal…
> Just to be clear: don't do that. Use CVDisplayLink.
I’m updating a very old app which does it the old way and is having trouble. QA1385 is clear, and yes I am moving on to CVDisplayLink. I would liked to have understood the trouble first, but maybe I’ll be able to get away with a shortcut this time.
Jerry
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden