Path: chuka.playstation.co.uk!news
From: "Alex Herbert" <aherbert@ndirect.co.uk>
Newsgroups: scee.yaroze.programming.2d_graphics,scee.yaroze.beginners
Subject: Re: Setting Multiple Bits in GsSPRITE
Date: Sun, 28 Feb 1999 19:56:33 -0000
Organization: PlayStation Net Yaroze (SCEE)
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Message-ID: <7bc7e3$abn5@chuka.playstation.co.uk>
References: <7bb6h9$9po30@chuka.playstation.co.uk>
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Rikki Prince wrote in message <7bb6h9$9po30@chuka.playstation.co.uk>...
>To set the Semi-transparency rate in a GsSPRITE structure, can I use
>attribute |= (3<<28); to set 1.0xBack+0.25xForward, and therefore
>attribute |= (2<<28); for 1.0xBack-1.0xForward?

Yep, that's fine.

>Or do I have to use
>attribute |= (1<<28);
>attribute |= (1<<29); for 1.0xBack+0.25xForward

I'd avoid doing it in multiple statements.  If you do need to set multiple
bits, it would be neater to compund the statements like:

attribute |=(1<<28) | (1<<29);

as you can be sure that the compiler will evaluate the complete expression
at compile time.  Personally, I'd do it like:

attribute |= 0x50000000;

but then I love hex.  At the end of the day, it doesn't matter much.  Use
whichever way makes most sense to you - at the end of the day it will
compile into similar code, if not idenical.

>and
>attribute |= (1<<29); for 1.0xBack-1.0xForward?
>
>Thanks in advance to anyone who can help
>Rikki
>
>


Herbs