Re: zwritemask modification

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John Rohlf (jrohlf++at++tubes)
Tue, 23 Nov 93 12:27:55 -0800

>Trying to modify the zwritemask (to 0x0) for entire branches of the
>database tree we found that Performer re-enables the z-writing
>(for example while drawing light points or transparent geometry).
>
>So I have the following questions:
>
>1) Can I tell Performer to keep the zwritemask at the given state?

        Not at this time.

>2) Is there a list of Performer functions where zwritemask is switched?

        pfTransparency and pfDecal(PFDECAL_BASE_DISPLACE) both set
        zwritemask.

>3) In those functions, is the zwritemask switched at the end of the
> function or somewhere in the middle?
> If the latter is true I think I have to avoid such geometry !
> For the first I would have to live with zwritemask(0x0)'s in
> all (critical) post draw callbacks.

        pfLightPoints and pfLayer nodes call pfTransparency and pfDecal
        respectively. You can choose to use stencil-type decaling
        with pfLayerMode(layer, PFDECAL_BASE_STENCIL) which will
        not modify the zwritemask.

        To get around pfTransparency setting the zwritemask you will
        have to use post-draw callbacks on all transparent geometry
        to be safe. Alternately you can globally disable transparency
        with pfOverride.

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