Re: [plib-users] Hidden Line Removal

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

Devrim Erdem wrote:
> 
> > Pass 1: Render all the geometry in completely transparent polygons
> >         ...make sure you have glAlphaFunc set so that the DO actually
> >         render.  As an alternative, you could draw the scene with it's
> >         'normal' alpha values - but tell GL to mask off the colour planes.
> >
> > Pass 2: Use glPolygonOffset to move everything a tad closer to the eye
> >         and then re-render the geometry in wireframe mode.
> 
> If I was doing pure opengl I would draw two passes sequentially. But while
> using a scene graph where shall I do the first and the second pass ?

The general idea is to call ssgCullAndDraw twice - once for each pass - with
different things overridden each time.

>  I am planning to draw 1st pass in a predraw and set the state for the second
> pass at the end of the predraw func. This way draw function will automatically
> do the second pass. I wonder how do PLIB'ers do multipass rendering normally.

That doesn't work for this though - you really need to draw ALL of the
Z values before you draw ANY of the wireframe polygons.


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