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experiments with 3D Anaglyph and stereoscopic output...

Posted by BGB, 20 July 2013 · 424 views

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).

or such...

3rd Test:

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.

Oculus Rift support... :)

still waiting for it to get shipped out...


but, yeah, probably shouldn't be too hard to support once I get one.


for the time being, all I really have are 3D anaglyph glasses, which cost around $3.75...