Re: pm3d question

[Hans-Bernhard B. <br...@ph...>]

Petr Mikulik wrote:

>>> enabling HIDDEN3D_QUADTREE.
[...]
> Unfortunately it is a compile-time switch.
> If it works, and gives good results, then make it as default.

I will.

>> The only real alternative would be to a full-featured, 
>> object-precision 3D rendering engine to replace both pm3d (polygons) 
>> and hidden3d (wireframe) output.  Such a beast would probably be even 
>> slower than hidden3d already is.

> Do we really want (need) a full virtual reality engine in gnuplot?

It doesn't have to be a VR engine (no interaction or real-time 
efficiency strictly needed), but yes, to resolve the problems inherent 
in the naive approach to 3D sorting currently being discussed for pm3d 
here, it would need to be quite a complete 3D engine.  Worse yet, I 
don't think any such renderer exists yet --- pretty much nothing out 
there is done in object precision (i.e. returns results in terms of real 
drawable objects, not just coloured screen pixels), these days.

Whether we *want* such a beast inside gnuplot, is the tricky question. 
Sorting pm3d polygons as if they're points will create nasty artifacts, 
and they'll be far from rare.

As I said to Ethan before: if you you want to hide non-polygon stuff, 
hidden3d is the way to do it.