Xref: utzoo comp.sys.mac.programmer:4044 comp.sys.mac:25464
Path: utzoo!attcan!uunet!munnari!basser!natmlab!ditsyda!vincent
From: vincent@ditsyda.oz (David A. Vincent)
Newsgroups: aus.mac,comp.sys.mac.programmer,comp.sys.mac
Subject: Re: Fast image changes
Message-ID: <1453@ditsyda.oz>
Date: 24 Jan 89 08:09:34 GMT
References: <243@usage.csd.unsw.oz>
Organization: CSIRO DIT Sydney, Australia
Lines: 35

in article <243@usage.csd.unsw.oz>, grants@usage.csd.unsw.oz (Grant Sayer) says:
> Xref: ditsyda aus.mac:414 comp.sys.mac.programmer:2784 comp.sys.mac:18246
> 
> 
>  	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.  

>that Turbo Pascal failsto allow procedures to be passed using the @ 
>operator on the procedure name thereby preventing installation of the 
>drawing procedure into VBInstall

TP allows you to apply @ to proc. or func. and pass the resulting
pointer to an assembly-language routine (which I think is all you need
to do).  TP does not allow you to use such a pointer except to pass it
around as a parameter.  
> 
> 	Any comments or suggestions would be appreciated
> 
> Thanks in advance

You're welcome.  

> Grant Sayer (grants%usage.csd.unsw.oz@munnari.oz)

David A. Vincent          vacation student, CSIRO Division of IT
ACSnet:     vincent@ditsyda.oz            Post:  GPO Box 1710-T
Phone (w):  +61 2 887 9383                       Hobart TAS 7001
FidoNet:    3:670/700                            Australia
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Common sense is not all that common.        -- Bertrand Russell.