Context Free Design Grammars for POV-Ray

ContextFree is a kickass free program for rendering fractal-like images from context free design grammars. I've been playing wiht it a lot recently and wanted to do something simmilar in 3d using POV-Ray. This is the first beta version of a script to do that. The language is not fully supported yet and there is some new stuff I'd like to add. Bug reports, comments, and images to my gmail address, I'd love to see what you make with this thing :-)

[Download source code]

rules go here:

instructions

This program is meant as a 3d approximation of the excellent Context Free renderer, so you'll need to learn to use that first. The syntax for myCFDG3d is mostly the same, except that r (rotate) becomes rx and ry to rotate on the x and y axes, and objects can now also be transformed on the z axis. CIRCLE becomes SPHERE, SQUARE becomes CUBE and I've added a new shape, CYLINDER. No TRIANGLE as yet, flip and looping not yet supported.

TODO

Check the math for object-space rotation, I think there may be a bug there.
Support more shapes, and user-defined shapes.
Support HSL color, alpha blending, as with Context Free.
Think about implementing transparency, refection, textures and other POV-Ray stuff.
If there is interest, add a user gallery, as at chriscoyne.com

Ideas

Add rand(min - max) as an option for variables, as in:

somerule {y 1, z rand(3, 10), rx rand(20, 50) }

Terminating cases - allow rule definitions reference another rule to switch to once object space reaches a certain size, eg:

rule STALK 100 terminate 0.3 FLOWER { CIRCLE {} STALK {y 1, rx 1, size 0.97 } }

In this case STALK behaves normally until object space becomes 0.3 the size of world space, then FLOWER is called in its place. Not quite context free.

Limitations

This copy of the program only runs to four thousand iterations. I know that's not lot. Generating million line text documents, several at a time, would affect the other sites running off this server. Ideally the server would also render the POV-Ray script to an image, for this heavily loaded box it's too expensive in memory and CPU time. If you can host a mirror with higher spec, please let me know an I'll link you from the front page. Thanks :-)

Example

context free design grammars with povray


startshape tree



rule tree {

     	branch { ry 30, rx 30 }

     	branch { ry -30, rx -30 }

     	branch { ry -30, rx 30 }

     	branch { ry 30, rx -30 }

}



rule branch 10 {

     	CIRCLE {}

     	branch { y 1, ry -5, size 0.95 }

}



rule branch 10 {

     	CIRCLE {}

     	branch { y 1, ry 5, size 0.95 }

}



rule branch {

     	CIRCLE {}

                 branch { rx 20, size 0.95 }

                 branch { rx -20, size 0.95 }

}



rule branch {

     	CIRCLE {}

                 branch { ry 20, size 0.95 }

                 branch { ry -20, size 0.95 }

}