Path: chuka.playstation.co.uk!news
From: developer support <dev_support@interactive.sony.com>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: CLUT troubles!
Date: Fri, 01 Aug 1997 11:43:56 +0000
Organization: PlayStation Net Yaroze (SCEE)
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Chris Chadwick wrote:
> 
> 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.

We've not come across this, and have to trouble changing all the CLUT 
values. Only thing I can think of is that you haven't called DrawSync 
after the MoveImage. If you want the CLUT to take effect immediately the 
DrawSync is crucial. 

> 
> 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!? :(
>

The CLUT has to be aligned to a 16 pixel boundary
 
> 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

If you can post the code we'll have a look at the CLUT changing bit.

Stuart