Path: chuka.playstation.co.uk!news
From: Chris Chadwick <xjk18@dial.pipex.com>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: CLUT troubles!
Date: Fri, 01 Aug 1997 02:25:14 -0700
Organization: PlayStation Net Yaroze (SCEE)
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Can anyone *please* explain what's happening here:

I have a simple 8-bit (256-colour) TIM displayed as a
sprite. I want to copy new CLUT entries into the
256-colour CLUT associated to the sprite by using
MoveImage(), which works when I change CLUT entries
0-15 (inclusive), but I can't seem to over-write
entries 16-255. The same is true if, for example,
I use ClearImage() to over-write each CLUT entry
in turn by pressing a joypad button: I'm able to
change entries 0-15 but anything else is ignored.

I've printed all the relevant variables as I go and
all seems fine. I've even used a 'test' TIM which
simply shows blocks of all 256 colours in the CLUT -
using the above example, as I keep pressing the button
each colour changes as I'd expect until it gets to
CLUT entry 16 then, nothing!

Another oddity I discovered is that if I place the
CLUT with a tpage X offset other than 0 (i.e. not
aligned with the left-hand edge of the tpage) then
simply displaying the sprite causes all colours to be
'shifted' in the displayed image by however many the
CLUT tpage X offset is e.g. If I have my CLUT at
frame buffer address X=1, Y=480 (instead of X=0, Y=480)
then pixels in the image that should be displayed using
CLUT entry 1 are displayed with the colour of CLUT
entry 0 etc. Again, I've displayed all settings and all
is reported as normal: the GsSPRITE member .cx is shown
as 1 but appears to be using 0!? :(

I wasn't aware CLUT's have to be aligned with tpages,
certainly, Tim Tool allows them to be positioned anywhere!

I hope I've explained the problems cleary enough.
Any help would be *much* appreciated!

Thanks in advance,

Chris