experiments with 3D Anaglyph and stereoscopic output...
here is the result of one test (for stereoscopic 3D output):
note: MovieMaker and YouTube seem to be conspiring against me on this one, basically making it a challenge trying to get a video with the correct aspect ratio.
and a slightly earlier test of direct anaglyph output (intended for green/magenta 3D glasses):
since then, I have gone and fixed up some things such that I can use higher resolutions, and also things like aspect ratio are tunable parameters.
in both cases though, for stereographic rendering, the image is naturally an awkward size.
I can render things scaled correctly with a video aspect of 8:3 or 32:9, but the video is basically a bar, and limits on horizontal resolution limit the vertical resolution, and MovieMaker inserts ugly black bars for everything that isn't 4:3 or 16:9.
this was what happened for the first stereo-3D video test (which came out looking awful):
for the later one, I rendered at a slightly higher resolution and with the image shoved into a 16:9 frame (to avoid the black bars), but alas it didn't come out at the correct aspect ratio (I rendered for 4:3, but YouTube displayed it at 16:9).
I could do a 3rd test, but I will leave it until later.
likely this would mean rendering/recording at 1280x720 or 1600x900 with dual 16:9.
this would work, but would halve the effective horizontal resolution (800x900).
note that a lot of this is also effectively limited by my monitor resolution (1680x1050).
note that for both stereographic and anaglyph modes, the scene is only rendered once and then warped as a post-processing effect to create the left/right views (the premise being that this is cheaper than rendering the scene twice, even if the quality is not as good).
more experimentation and fiddling continues, along with trying to find the ideal settings for stereoscopic 3D.
I spent a while trying to figure out some math in the shader, later realizing that the 'relevance' of the variable amounted mostly to a constant factor. some other math works, somehow...
not really sure if there is any standardized definition of stereoscopic vision.
from what I can tell, it is mostly a matter of divergence from a center point, with the divergence increasing with distance (implying that each eye looks slightly outward, rather than straight forward or slightly cross-eyed). there is also a certain factor due to approximate eye distance.
most 3D content I have found, for whatever reason, seems to diverge much more rapidly than what feels natural to myself, and often to a degree where keeping the images integrated is difficult. I have generally gotten a more comfortable and natural effect using a smaller divergence.