Lisp Package Dependencies October 21st, 2008
Patrick Stein

Some time back, xach posted information about all of the interdependcies amongst the Lisp packages available on Cliki. He had toyed with a few visualization techniques.

Me, I tweaked some old code visualization stuff I had written to output where everything was after it stabilized. Then, I tweaked my ray tracer to read that input and render the output.

Read the rest of this entry ⇒

First decent images from my new raytracer September 25th, 2008
Patrick Stein

Some time ago, I wrote an n-dimensional raytracer in C++. It does a fair number of things, none of them efficiently, most of the rigidly.

There are a bunch of things that I wanted to do with it for a long time, but it’s been too slow and rigid to make any of those things fun.

Enter Lisp. As soon as it made it through my skull that Lisp is actually compiled (honest-to-goodness your-CPU instructions), I wanted to rewrite the whole thing in Lisp. I have finally gotten started on doing that. And, I just made it to the point where I’m actually tracing rays. Here is a stereo pair of a three-dimensional scene:

lrt-l lrt-r

Read the rest of this entry ⇒

rt v2.7.2007.05.17 May 17th, 2007
Patrick Stein

  • The documentation
  • The source code
  • The feature set now includes:
    • Phong shading, reflection, refraction
    • Functional textures (including textures generated by
      raytracing other scenes)
    • Cylinders (including spheres and cubes)
    • Quadratic surfaces
    • Regular polytopes
    • Halfspaces
    • Convex hulls of a sets of points
    • Extrusions of lower-dimensional objects
    • Intersections, unions, and complements
    • Different colors for k-dimensional subfacets
      of convex hulls and coxeter polytopes
  • Here are some sample images:
    • A stereo pair of slices of some 24-cells along with the input file. The vertexes (0-facets) are pink, the edges (1-facets) are dark gray, the faces (2-facets) are yellowish, and the facets (3-facets) are green.
    • Some 3-D polytopes with edges and vertexes colored differently and the input file.