Path: utzoo!attcan!uunet!cbmvax!vu-vlsi!swatsun!jackiw
From: jackiw@cs.swarthmore.edu (Nick Jackiw)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Fast image changes
Message-ID: <2350@ilium.cs.swarthmore.edu>
Date: 24 Jan 89 14:41:24 GMT
References: <243@usage.csd.unsw.oz> <1453@ditsyda.oz>
Reply-To: jackiw@ilium.UUCP (Nick Jackiw)
Followup-To: comp.sys.mac.programmer
Organization: Visual Geometry Project, Swarthmore College, PA
Lines: 28

In article <1453@ditsyda.oz> vincent@ditsyda.oz (David A. Vincent) writes:
> in article <243@usage.csd.unsw.oz>, grants@usage.csd.unsw.oz (Grant Sayer) says:
> >  	I am trying to draw two images one on an offscreen pixelmap and then
> [...]
> >code which swaps the images, basically a copybits operation, into the VBL 
> >task queue seem a viable solution.  If this is the casethen is it true
> 
> This seems viable provided that the copybits can be completed during
> the VBL period.  
> 

Much easier is just to coordinate your copyBits with the VBL interval.  
You can do this in Pascal by waiting for the system timer to tick, something
which happens as a system-VBL task.

	var x:longint;

	Delay(1,X);	{Wait for next VBL interval}
	Copybits(...);	{Here we go, do it fast!}

Follow-ups to comp.sys.mac.programmer ONLY.  Eradicate cross-posts!


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+-------------------+-jackiw@cs.swarthmore.edu / !rutgers!bpa!swatsun!jackiw-+
|  nicholas jackiw  | jackiw%campus.swarthmore.edu@swarthmr.bitnet           |
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