Stereoscopic cameras render the scene incorrectly

[RaananW]

When rendering the scene using a stereoscopic camera (side by side or over-under, the scene renders incorrectly.

The current behavior:

The expected behavior:

[foxxyz]

Is it possible this change has broken the interlaced stereoscopic view (Camera.RIG_MODE_STEREOSCOPIC_INTERLACED) added in #7425? Looking at the changes in your commit in stereoscopicRigMode.ts, there are no more checks for Camera.RIG_MODE_STEREOSCOPIC_INTERLACED and setting this rig mode now seems to incorrectly add separate viewports and shows identical output to Camera.RIG_MODE_STEREOSCOPIC_SIDEBYSIDE_PARALLEL.

Client workaround for vertical interlacing seems to be:

camera.setCameraRigMode(Camera.RIG_MODE_STEREOSCOPIC_INTERLACED, { interaxialDistance: 0.0637 })
camera._rigCameras[0]._rigPostProcess = new PassPostProcess(camera.name + '_passthru', 1.0, camera._rigCameras[0])
camera._rigCameras[0].viewport = new Viewport(0, 0, 1, 1)
camera._rigCameras[1]._rigPostProcess = new StereoscopicInterlacePostProcessI(camera.name + '_stereoInterlace', camera._rigCameras, false, true)
camera._rigCameras[1].viewport = new Viewport(0, 0, 1, 1)

But this seems like it should be patched back in as a post-processor in Camera._setStereoscopicRigMode()...

Let me know your thoughts.. Happy to submit a PR if needed. Thanks!

[RaananW]

Hi @foxxyz - this is more than possible :-) We just want to be sure that the window ratio pre and post resizing stays correct.

If you want to open a new issue for this, or even submit a PR with a fix - please go right ahead. Make sure to reference this PR (and me if you want me to review it).

[Hannes3112]

Hi @RaananW
The Stereoscopic cameras are still rendering not correct because they are using the toe-in method rather than an Off-Axis projection. This introduces so called vertical disparities which are quite problematic as they are hurting the eyes and scenes becoming difficult to watch:

The correct method is called Off-Axis projection, which can be achieved via camera matrix manipulation (shifting the virtual sensor on its x-axis) or viewport cropping. I would be very happy to help with the mathematics / logic and with testing (but not with code, I'm not a programmer).

It would also be very nice if the isStereoscopicSideBySide property could be set to squeezed mode because almost all stereoscopic displays with SbS or TB input need it in Half (squeezed) mode, like this:

So, the initial output was not wrong, it was just missing the option to set it to SbS/TB Full (which it is now).

[Hannes3112]

Here is a very comprehensive text about the topic:
http://paulbourke.net/stereographics/stereorender/