Stereoscopic Display

Using two monitors, a mirror, and a bunch of clamps, I built a stereoscopic display.

To view the display, you sit with your face up to the mirror, which is represented by the black rectangle in this picture.

If you look straight at the left monitor, your left eye will see this monitor directly, and your right eye will see a reflected image of the right monitor superimposed over the left monitor.

Because each eye sees a slightly different image, the illusion of depth is created.

I used two 21 inch high-res monitors. Since there are no LCD shutters, the display is bright and the frame rate is high and there is no flickering.

The depth of the 3D display is about six inches. Anything outside this range will cause eye strain, because you’re trying to converge your eyes at a distance that doesn’t match up with the plane that you’re focusing on (which is always the plane of the screen.)

I have created a few stereo pair images from scenes in the PDI computer-animated film Antz, but I can’t show them here.


3D Asteroids

Here’s a screen shot of an extruded version of Asteroids that I made for the stereoscopic display.

There are six controls that orient the ship, although in practice only four are used. I tried to make the game as close as possible to the original in terms of game play.

When the game says “Press 1 or 2 player start” I use exactly the same font as the original game. Eric Snider lifted the sound resources from the Macintosh version of Microsoft Arcade, so I have exactly the same sound effects as the original.

The topology of the real Asteroids game is a torus. The 3D version is a hypertorus because it wraps around from front to back as well as side to side.

A big question when I started writing this game was if it would be playable at all. Originally it wasn’t, because the asteroids were smaller and in 3D there’s a lot more empty space than in 2D. I increased the size of the asteroids and the ship and everything balanced out.

While playing the game, it’s useful to constantly reorient your ship so that it lies approximately in the plane of the screen. If you allow the ship to become upside down and backwards, it becomes harder to control.

The stereo effect is quite good, and with a little practice, you can shoot down into the screen at an angle and pick off a passing rock in the background.

The game requires two computers, one generating the image for each eye. One computer runs the game and tells the other machine what to draw next via the network.


Mars Panorama

When Pathfinder touched down on Mars, I wrote stereoscopic panorama software for the 3D display. The left and right cursor keys are used to scroll the display 360 degrees.

I used the high-res stereo panorama image that was posted to the web by JPL. The image was designed to use red/blue glasses, but I was able to extract the left and right stereo pairs out of the red and blue channels of the image. Unfortunately this only allowed for a gray image.

The images above were created with a monoscopic full color version of the panorama.

Also, since I only get about six inches of depth with my viewer, the horizon appears to be squashed up at about arm’s length. Nevertheless, it’s fun to look around and become familiar with the area of Mars immediately around the Pathfinder.

I’ve heard that on the Cassini probe to Saturn’s moon Titan, a microphone was installed. If they get any good recordings, it will be cool to sit in a dark room and listen to them with headphones and imagine you’re really there.

Update: The microphone thing was a total letdown.

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