By Bill Graham, Graphics Editor, firstname.lastname@example.org
Early last year, I authored an article on using ADPro to make anaglyphic stereo imagery for the Amiga. Since then, I have received several requests for an article on making stereo imagery with ImageFX. IFX has the distinct advantage over ADPro in that it is still supported (Nova Design) and is still available. In fact, they have just announced a major upgrade, ImageFX 3.0. I am ordering this upgrade today, and will review it in an upcoming issue of the AM.
This IFX method of creating stereo anaglyphs has several advantages over the ADPro method. First and foremost is the fact that you create a 24-bit color image, which can then be dithered down into one of the Amiga display modes if you do not have a graphics board. Secondly, IFX supports color channels, which makes interlacing a stereo anaglyphic image unnecessary. And thirdly, this type of stereo anaglyph can be output to videotape, which opens up the possibility of stereo TV!
I've always enjoyed stereo pictures. I had a Viewmaster when I was a kid, and would always check out the latest 3D movie as soon as it would come to the local theater (yeah, I'm dating myself...)
In 1989, when Impulse released Turbo Silver 3.0 for the Amiga, they offered it as an upgrade to previous users along with the stereo LCD glasses from Haitex, which I still have. They work on a slow scan rate monitor like the 1084 only. There is quite a lot of software that supports the creation of stereo imagery, like Imagine, VistaPro, and others. If you are fortunate enough to have a digital still camera or a camcorder and framegrabber, you can convert those images into Amiga stereo pictures also.
I was never happy with the necessity of owning expensive special hardware to view stereo pictures and animations, and I worked to find a way so that any Amiga owner could make and view stereo stills and animations. I came up with a method that works on both ECS and AGA machines and also with 24-bit display boards, and it allows the user who wants to create stereo imagery the ability to tailor the resolution and color depth to fit his machine and monitor setup.
What I did was come up with a way of making anaglyphic stereo imagery viewable on any Amiga monitor. The anaglyphs in this case are monochromatic, or shades of one color. But the only hardware you need to view them are the red/blue glasses found in comic book stores and in variety shops. You can also order some from Reel 3D Enterprises in Culver City, CA. at 310-837-2368. This article will guide you through the process of making these pictures.
This how-to assumes several things. Firstly, that you have a source for stereo pictures, or the software to create your own. Secondly, you must have ImageFX, the image processor from Nova Design. And, you must have a basic knowledge of Amiga graphics.
Anaglyphic stereo pairs need to be made into red and blue images. Traditionally, red is for the left eye and blue is for the right. So, you must use IFX to process the two images as follows.
First, you load the left view. You then use the "Color To Gray" option in the Color menu to strip the color from the image. And you must then use the "Gray To Color" option from the same menu to give the image a Color Look Up Table, or CLUT. This is necessary for the image to have all three RGB color channels available for further processing which will be needed later. Using the Buffer menu, do the "Copy To Swap" command, which places this image into the Swap buffer. You may want to save the image to disk, just in case you make a mistake.
Now you load the right view image. With this image, you do the "Color To Gray" as outlined above. But do NOT do the "Gray To Color" command. Instead, it is necessary to do some palette manipulation.
ImageFX allows you to work with several 256-color palettes. Although you are working in either 24-bit color space or 8-bit gray mode, ImageFX's use of multiple color palettes allows for some special processing capability.
The palettes come as eight Draw Palettes and one Render Palette. For this exercise, we need to manipulate the Render Palette. Clicking the Palette button brings up IFX's extensive Palette manipulation window. At the top right of this window, you can see some up and down arrows. Click on the up arrow until all of the color pots are displayed. Just below these arrows, you can see the Palette selector. Click this until Render is displayed (as opposed to Draw1, Draw2, etc.)
Now click on the upper leftmost color pot, and use the sliders to make this color 0,0,0 on the RGB scale. Click on the bottom rightmost color pot, and make this one 0,0,255, or pure maximum blue. With this color pot still selected, click Spread, then click the first color pot. You should see a smooth range of 256 shades of blue. In the lower left of this palette manipulation window, there is a toggle button that says either Lock or Unlock. Make sure Unlock is displayed. This locks the rendering algorithm to the blue palette you've just created. If you'd like, you can save this palette for future use.
Click the Render button in the lower section of the window (NOT the Render palette button mentioned above). After a moment or two, you will see your grey image transformed into shades of blue. Save this rendered image to disk. Make sure you select Rendered from the save requester.
Go back to the Toolbox window. Now load the blue image you just saved. IFX will load it as a 24-bit image, with all three color channels available. Double-clicking on the Fill tool brings up the Fill Options requester, and you will see several buttons. Leave everything at the default, except for Style, which you want to set to RubThrough.
At the top middle location of the toolbox window, you'll see three radio buttons labeled R,G, and B. The default state for these is on. You want to turn the G and B buttons off, so that they are "raised," and so that only the R button is on, or "depressed."
With the Fill tool selected, click anywhere in the main window that is displaying your blue image. You should soon see the red portion of the image in the Swap buffer merge with the blue image in the main view. This is your stereo picture, in 24-bit color. If you have a 3rd-party graphics board such as an OpalVision or Picasso, you can view the image as it is. You can use any of IFX's tools to adjust the brightness or contrast of this image, or to make it NTSC "legal" for video display. I do not recommend adjusting the RGB sliders. Doing so will destroy the red/blue color balance vital to maintaining the stereo effect.
To make an Amiga-displayable image from this 24-bit picture, you will need to bring up the Render window (not to be confused with the Palette window) and choose which Amiga rendering mode works best for your particular setup. To enhance the stereo effect, you may want to try locking the palette as mentioned above into shades of red and blue. On an AGA machine, I've found that this step is not necessary. I simply render the 24-bit file as a HAM8 image and it displays nicely.
You can see some examples of stereo stills created in this manner by going to my website at http://www.tonguemonster.com.