A Party to the World » ray tracer

Stanford Bunny

Dan — Mon, 04 May 2009 06:16:52 +0000

The Stanford Bunny is a graphics benchmark of sorts. It was a high-resolution scan that the imaging lab there did of a ceramic bunny, and the triangulation is a popular model to test systems on.

It contains a little under 70,000 triangles which makes brute-force ray tracing intractable. I mentioned octtrees earlier, and so having built octtrees into my ray tracer, I was able to render the Stanford Bunny in about 40 minutes on one core. Granted, that’s with only 1-pass anti-aliasing, but I feel pretty good about this. I don’t think I’ll have a chance to implement Gouraud shading (or normal interpolation for that matter), but as soon as I do, it will look a lot less blocky.

The Stanford Bunny rendered with my ray tracer.

Orbits

Dan — Thu, 30 Apr 2009 21:29:31 +0000

Orbiting planets. The days are about twice as along as they normally are relative to each planet’s year, but that’s an aesthetic preference. Enjoy.

New Render

Dan — Mon, 27 Apr 2009 04:56:54 +0000

I got a new render up from my ray tracer that applies planetary textures to spheres and makes them spin on their respective axes (none of the planets in our solar system spin on a “vertical” axis). I hope to do one with their orbits, but I haven’t had a chance to get to it; though, the nice thing is, I just have to define their paths and rotations as a function of time, and where I want the viewpoint to be. It took about 15 minutes to render in full HD 1080×1920 on 18 processors:

Ray Tracer – Texturing Support

Dan — Fri, 24 Apr 2009 18:26:51 +0000

It’s all well and good to be able to render shapes in space in a photorealistic way, but at some point you’d like to draw something that doesn’t have just one surface color. After all, a billboard isn’t just a bunch of shapes each of which has one color – it’s one object with paint / ink placed on it in an ordered way.

Texturing accomplishes by taking a primitive shape (like a sphere, triangle, surface of revolution, etc.) and wrapping an image onto and over it. Let’s consider a sphere in space:

A white sphere in space.

Now let’s say we mean it to be Earth. Then we can take a picture of Earth that’s flat:

Flattened map of Earth

and then map it onto a sphere to get a picture of what we all know Earth to look like:

Behold!

Two Mars globes where the left is what is seen with the eye, and the right is a topographic map.

Ray Tracer – Now With Animation

Dan — Tue, 07 Apr 2009 03:16:04 +0000

It occurred to me today that I could render a scene several times with slight perturbations and then mesh them together into a movie. It took about 15 minutes to render on a cluster at Mines, and then about a minute to stitch together with Mencoder. At 18 frames per second, here is the result. Enjoy!