Path: chuka.playstation.co.uk!news
From: "John \( QuietBloke \)" <quietbloke@btinternet.com>
Newsgroups: scee.yaroze.freetalk.english
Subject: Re: Buggery Title Screen!!
Date: Wed, 29 Aug 2001 20:14:51 +0100
Organization: PlayStation Net Yaroze (SCEE)
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Are all the textures located at the top left corner of a texture page ?

GetTPage seems to like returning a PageID only if you supply the top left
corner
of a Page. If your image is offset within a page it wont work.
Does that make sense ?

The manual mentions this saying the texture page address is limited to
multiples of 64 in the x direction and multiples of 256 in the y direction.
( its a bit cryptic to say the least ).

In the supplied tutorial files there was a routine ( see below ) where you
pass it an image info and it returned x and y as the top left location of
the texture page and u,v the offsets within the page of your image. If you
call this and then supply the returned x,y values to GetTPage it should
work.

void FindTopLeftOfTexturePage ( GsIMAGE* imageInfo, int*x, int *y, int* u,
int *v )
{
 int testX;
 int testY;

 testX = imageInfo->px;
 testY = imageInfo->py;

 *u = 0;
 *v = 0;

 for ( ;; )
 {
  if ( testX % 64 != 0 )
  {
   testX--;
   (*u)++;
  }
  else
  {
   break;
  }
 }

 for ( ;; )
 {
  if ( testY % 256 != 0 )
  {
   testY--;
   (*v)++;
  }
  else
  {
   break;
  }
 }

 *x = testX;
 *y = testY;
}


Alternatively you could do the following which seems to work for me when Im
loading 8 bit tims.

 spriteLogo.tpage = GetTPage ( 1, 0, imageInfo.px & 0xffc0, imageInfo.py &
0xff00 );

which basically masks off the right most bits so you end up passing an x
value as a multiple of 256 and y value as a multiple of 64 as required.

Hope this makes sense and helps.

Cheers
John ( Quietbloke )