Re: [grt-talk]Lisp coder position

[Nikodemus Siivola]

On Fri, 28 Mar 2003, Jason Dagit wrote:

> I browsed the online CVS repository and looked at the webpage.  Are
> the images on the webpage from the C version or the lisp version?

Lisp.

> I would like to if at all possible convert it to use openGL, and perhaps
> get some of the rendering done in hardware if it would help.

You could use OpenGL to display the images as they are rendered, sure. You
could probably use some bits of OpenGL for other things as well. An OpenGL
preview would definitely be cool.

You can't really get any increase in the raytracing speed by going that
route -- at least not without tying yourself to the OpenGL and rendering
lighting models, etc. And then you would not be raytracing anymore...

However, if you have OpenGL experience, I would definitely be interested in
using it for previews.

> I use Debian's GNU/Linux distro
> (currently using unstable).  I have several Common Lisps.  My favorite
> is clisp, then cmucl.  Clisp is great fun to use, but cmucl has better
> support for interfacing with c code.

To do something as floating point intensive as raytracing you are better of
with CMUCL. Also, as a bonus it should make life easier with both of us
using CMUCL. On the negative side, there is more danger in becoming to
CMUCL specific.

> Have you checked out cl-sdl?  It has code that works with cmucl so that
> you can use openGL and the sdl.

I've had a look at it, but not actually tried it. The current CLX-based
rendering window sucks to such a degree that I think replacing it with dsl
might not be such a bad idea...

> I don't know how you are specifying scenes right now, but I had an
> idea that we could create an extension to Common Lisp using macros and
> functions and the lot so that you actually use lisp to define a
> scene.

That's exactly the idea: GRT is currently more of a raytracing API than
anything else. There are some other ideas I've had as well, but for me at
least the focus currently is in writing the raytracing engine.

> Do you have support for different graphic formats yet?  Perhaps I
> could look into adding support for that.  Hmm...I think I need to try
> out the code.  That would answer a lot of my questions.

Currently no. Just hacked a quick PPM output and that was it. There is a
cl-png packege, that you might want to look at.

> Did you know that you can download some really great lisp references
> on the net?

Yup! ;)

> reference for advanced lisp programming.  The same goes for "Paradigms
> in Artificial Intelligence Programming".  I know a fair amount of

I thought only the code was available? Is the text somewhere as well?

Oh -- I'll try and see if I can scrounge up some of my raytracing & 3D math
links and post them here and on the homepage. Sort of recommended reading.
Maybe a book list as well?

  -- Nikodemus