Path: chuka.playstation.co.uk!news
From: James Chow <james@chowfam.demon.co.uk>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: Hi-res question
Date: Wed, 20 May 1998 17:29:14 +0100
Organization: PlayStation Net Yaroze (SCEE)
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Message-ID: <356304D9.B623E918@chowfam.demon.co.uk>
References: <6jmvrs$35i1@emeka.playstation.co.uk> <3561930C.CDA794B5@hinge.mistral.co.uk>
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> > Try clearing the VRAM...
> 
> <SNIP - I banish George's dodgy idea to the dustbin of obscurity>
> 
> What you could actually do is use a rectangle instead of a clear...:
> 
>     // r,g,b = char's : the colour to clear screen to
>     GsBOXF my_box={0,0,GsGetActiveBuff()?0:512,640,512,r,g,b};
>     GsSortBoxFill(&my_box,WorldOt[GsGetActiveBuff()],(1<<OT_LENGTH)-1);
> 
> That'll do it.....
> 

I believe inserting these lines after modifying GsDISPENV
is the neatest way of clearing the background.

  GsDRAWENV.isbg = 1;
  GsDRAWENV.r0 = (red value);
  GsDRAWENV.g0 = (green value);
  GsDRAWENV.b0 = (blue value);

But it still does not tell me why GsSortClear doesn't work!
After a bit more testing of this problem, it has something to
do with the very bottom line of the screen - definitely.

Setting the height to 510, 511 and GsSortClear() works. But
the problem starts when trying to use the max 512 lines.
GsSortClear() fails to work. OK, so we use a workaround.
We manually clear the backgound (using above examples),
simulating GsSortClear() (nearly!). But I looked very carefully
at the screen, at the bottom line is NOT cleared, say when
I move a sprite over it.

This is seems like the classic bug of "counting from 0",
giving a 1-off result.
Anyone?
-- 
jc