OpenGL stereoscopic anaglyphs and patents

An anaglyph is a combination of two images into one, in such a way that they can later be separated by viewing the image through appropriately colored transparent filters. The objective is to present slightly shifted views of the same 3D environment to each eye, in order to achieve depth perception (i.e. really perceive the 3rd dimension).

I’ve never dealt with anaglyphs in the past, but during my recent week-old obsession with stereoscopy, I’ve stumbled upon a pair of free anaglyph viewing glasses (made out of cardboard and cellophane of course). So I couldn’t help but try to find out how I can use them with my own programs.

FreeGLUT spaceball patch

The original GLUT library used to support some less well-known input devices under IRIX, such as the Spaceball, a true 3D input device which can be used to control all 6 degrees of freedom (3 axis of rotation and 3 axis of translation) simultaneously. Unfortunately, nowadays, the more “exotic” input callbacks of GLUT such as the spaceball are left unimplemented.

So, yesterday I sat down and implemented the missing spaceball bits of FreeGLUT, which is the most widely used free GLUT implementation.

To avoid adding any extra dependencies to freeglut, I just ripped the relevant code from libspnav, which is part of my free spacenav driver project, and added it directly into freeglut.

Here’s the patch against the current freeglut svn head, as well as instructions on how to check out freeglut and apply it.

I’ve also submitted it to the freeglut-devel mailing list, so hopefully they’ll merge it and we’ll have spaceball input callbacks available with the prepackaged glut that comes with any GNU/Linux distribution in the future.

S-ray goes public

S-ray is a photorealistic off-line renderer I’ve been writting on and off for the past few months. It’s basically a monte carlo ray tracer using the photon mapping algorithm to simulate global illumination effects, such as indirect diffuse lighting and caustics.

So, it’s time to open up the code and continue development in the open. The code is available only through subversion at the moment, no official “0.1” release shall be made until at least the most important outstanding bugs are fixed. However, feel free to checkout the code and play around all you want.

The project is hosted at googlecode, and you can find it at: http://code.google.com/p/sray
As always, ideas, comments, or bug fixes are more than welcome.