Well  I believe POVMan can do "proper" shading within pov, though I've never 
had a play with it. Basically a ray-tracer is very well suited to shading, 
even when using radiosity, because all you're ever doing is calling a shader 
with an array of light colours coming from different directions (either from 
radiosity or light sources) and asking it to tell you the colour emitted in 
a specific view direction (for either a view ray, reflection, refraciton, or 
radiosity sample). Of course I've oversimplified a little but it should be 
pretty straightforward, just needs the syntax.

BTW, megapov's angle-of-incidence (aoi) pattern lets you fake lots of BRDF 
style shading, so you can overlay 2 of those patterns with one based on the 
angle to the camera and one based on the angle to the light.

-- 
Tek
http://evilsuperbrain.com

"Tim Nikias" <JUS### [at] gmxnetWARE> wrote in message 
news:45450fb6@news.povray.org...
> Tek wrote:
>> Actually as far as "shading" goes pov's pretty lame. e.g. conserve_energy 
>> only works on transparent things, which means if you want realistic 
>> gloss-paint you need a layered texture, and pov won't let you layer over 
>> patterned textures... Seriously these kind of restrictions have no place 
>> in a shader style language. In fact the whole syntax of the finish 
>> statement means you have to bend over backwards to do anything clever 
>> (like anisotropic shading, never mind BRDFs). Uh... oops looks like you 
>> touched a nerve... :)
>
> Hehe, yeah, after a couple of courses at my university I was thinking the 
> same thing. BRDFs, better layering etc would really be handy and to 
> current standards. Then again, there are always some that implement new 
> stuff, and in the recent years advances were rather fast-paced. People 
> like to use the new stuff, but there aren't that many able to understand 
> how they really work, let alone properly implement them into a versatile 
> and powerful environment such as POV-Ray (and no, I don't want half-a** 
> implementations like in Maya, where stuff crashes all the time). In some 
> regard, there's also the overhead to be considered: we all know how 
> radiosity and photons can start crawling with enough samples, simply 
> because a raytracer has to raytrace and there aren't as many quick, 
> GPU-accelerated approaches on that sector...
>
> Personally, I think that once POV-Ray would allow for multi-pass rendering 
> (e.g. with switches for lights on certain passes, object on/off etc), 
> people would be able to work around a lot of issues simply by rendering a 
> couple dozen passes, e.g. to simulate various light-samples and later on, 
> composite them. That's how I actually achieve quite a few effects anyways: 
> rendering the scene once or twice and using the results to enhance the 
> image (e.g. bloom or glares). I don't like how it's a a crude approach and 
> people using different software might get different results.
>
>> But the fact that you can describe objects using a language, so you have 
>> loops and conditionals and stuff, is just awesome.
>
> Total agreement on that.
>
> -- 
> aka "Tim Nikias"
> Homepage: <http://www.nolights.de>

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