Re: [Plib-devel] disappearing texture problem

[Steve B. <sjb...@ai...>]

Darrell Walisser wrote:
> 
> >From Brian Speece (ATI), commenting on bug :
> 
> > I can't speak for whether Apple has seen this, but we definitely haven't.
> > We'll download the framework.  It would be great if you could point us to a
> > test case that exhibits the problem.  The RagePro did not support alpha
> > modulate (i.e multiplying the texture alpha by the vertex alpha).  I'm
> > wondering whether this is involved.  In any case, we will look at it, and
> > tell you what we find.
> 
> Does this sound possible, Steve?

Well, I knew about that horrid restriction of the RagePro - and you can actually
see it in action on the screenshot you posted.

Look at the circle of golden herring at the bottom-left of the screen.

On a legal OpenGL implementation, each of those are rendered as 50% transparent
until you have collected that gold herring - and then rendered opaque
after that.  However, the texture alpha is also used to cut out the
shape of the fish - so for the fish you have *not* yet collected, the
50% vertex alpha *should* be multiplied by the texture alpha.

However, in your image, all of the herring are opaque - which either
means you are an EXCELLENT Tux player - or this is an example of the
error that Brian is talking about.

I'd point out that failing to support that means that their implementation
presumably isn't passing the OpenGL compliance test suite - which means that
it's not legally supposed to be called OpenGL!

You see the same vertex alpha bug under Windoze too BTW.

So, no - I don't think that's related to the 'missing opaque surface' bug.

Cutting this down to a manageable test case would be REALLY difficult...

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