Path: chuka.playstation.co.uk!news
From: shrewrs@aol.com (Robert Swan)
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: 2D sprites in 3D scenes?
Date: Sun, 08 Mar 1998 21:11:42 GMT
Organization: PlayStation Net Yaroze (SCEE)
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On Sun, 08 Mar 1998 19:17:52 +0000, Anna <amarsh@bournemouth.ac.uk>
wrote:

>Hi all.
>
>Have come up against a prob whilst attempting to put a 2D image into a
>3D  scene.  I have tried sending the sprite to the ordering
>table first, last and in between the two models, but to no avail.
>
>The sprites priority is set to 0, which I thought would make it on the
>top layer.  

Yep, it is possible to combine 2d and 3d graphics, as I'm doing just
that. The problem may be for the same reason I had to stop and sort
out my program. You said 'I have tried sending the sprite to the
ordering table first, last and in between the two models' but seeing
as the problem you have is identical to one I had, I still thought it
might help to check whether you did the following-

If you have a small depth of ordering table, or the objects are very
close to the viewplane, then they are likely to be placed in the OT at
priority position zero. To overcome this, there are a couple of
solutions -

Make the depth of the ordering table larger, so that the model's z
depths from the view plane do not have to be scaled down quite so much
when inserted into the OT. (A bit of a silly solution, but still
possible), or

do the GsSortSprite() function before the two GsSortObject4()
functions, so that if the two 3d models do end up with a priority of
zero (the same as the sprite) then owing to the OT's 'first in, last
out' operation, the models will get drawn first, and (hopefully) the
sprite will get drawn over them.

Robert Swan
rs108@mdx.ac.uk
http://www.netyaroze-europe.com/~middex2