vthrc@brolga.cc.uq.oz.au (Danny Thomas) (02/12/91)
Hello netters, One small project we've considered here is to allow viewing of stereo images on a mac. In our case this mainly means scanned stereo-pair photos taken with an electron microscope. Now a friend of mine has a product for the Amiga called XSpecs 3D, which I think is also available for the Atari and maybe others. It is a set of LCD goggles with the left and right eyes being blacked out for alternate video frames. It retails for around $100 and includes a 3D shoot-em-up game and software for displaying stereo images prepared with some commercial 3D packages. Adapting the goggles to be driven by the mac is probably quite easy but the question is how to display left and right views on alternate frames. Probably we'd need to have both images held in the video RAM and merely change the pointer to the start of the frame buffer. I've had a look at the "Display Card Developer Notes for the Macintosh Display Cards 4.8, 8.24, and 8.24GC" (M0857LL/A 6/18/90) but it says about the frame buffer controller "Your applications should never read or write directly to the hardware because the control registers won't be compatible with other manufacturer's cards. For this reason, the parameters stored in the JMFB's control registers are not documented in this preliminary note..." This is more than just a strongly-worded warning to remain hardware-independent (just look at the PC world where each application can require a driver for each possible display type, n*m combinatorial!), but I am happy to live with the consequences for a one-off piece of software. IMV describes that there are now separate queues for each video device to accomodate different frame rates, so that solves the synchronization problem (some jitter probably wouldn't matter given the slow response time of LCDs) but does anyone know how the hardware frame pointer register(s?) could be set, or is there an alternative approach that I could consider? Thanks in advance, details will be posted if we get it working. Danny Thomas, Vision, Touch and Hearing Research Centre, University of Queensland.