Day/Night lighting broken in 2D

[hpinkos]

It only
orks sometimes depending on where the camera is

viewer.scene.globe.enableLighting = true;

[hpinkos]

Also reported here: https://groups.google.com/d/msg/cesium-dev/vD3SiO5V6U8/-mMOU-bgCgAJ

[jeffwhitty]

+1, I'm seeing this with the November release. Found this while searching before logging a duplicate.

I noticed if I pan up and down it seems to happen as well as side to side, but I haven't spotted a consistent factor to narrow down the cause.

[cfairchi]

Still seeing this issue in 1.34. Any ETA on a fix?

[pjcozzi]

@ggetz could you please try to triage Cesium releases to see if this previously worked and find the commit that broke this?

[sspeaks]

I've found this issue to be introduced post version 1.21.0. Is there any ETA on a fix for this?

[hpinkos]

Thanks for tracking that down @sspeaks! This is marked high priority so we hope to have time to look at it soon, but our team is spread pretty thin right now. If anyone has time to look into it, we are always happy to review a pull request with a fix!

[emackey]

I ran git bisect on this. It was introduced in either f924c16 or its parent commit 041ee30 (these are both work-in-progress commits). The parent of those commits b590677 did not display the problem.

These commits were merged to the old models-2D branch as part of #3933, and that branch was later merged to master.

(For my own reference, what follows below is the Sandcastle snippet that was bisected)

var img = Cesium.createDefaultImageryProviderViewModels();
var len = img.length;

var viewer = new Cesium.Viewer('cesiumContainer', {
    imageryProviderViewModels: img,
    selectedImageryProviderViewModel: img[len - 1]
});
viewer.scene.globe.enableLighting = true;
viewer.scene.morphTo2D(0);

[ghost]

I must admit I am kind of ignorant of frustums and 3d graphics, so take this with a grain of salt.

if (!is2D) {
     curNear = Math.max(near, Math.pow(farToNearRatio, m) * near);
     curFar = Math.min(far, farToNearRatio * curNear);
 } else {
     curNear = Math.min(far - nearToFarDistance2D, near + m * nearToFarDistance2D);
     curFar = Math.min(far, curNear + nearToFarDistance2D);
}

This bit of code seems to be the culprit in the more recent version of Scene.js.

If you use the code in the if (!is2D) block for all cases(including 2d), it seems to eliminate the problem. Similarly, increasing nearToFarDistance2D from 1.76e6 to 1.76e7 also fixes the issue.

//i.e. Just use this instead of the if/else
curNear = Math.max(near, Math.pow(farToNearRatio, m) * near);
curFar = Math.min(far, farToNearRatio * curNear);

I'm sure either of those fixes breaks countless other things though. I would be happy to try and fix this with a PR, but I fear my lack of knowledge on the subject would waste your time with reviews.

[hpinkos]

Thanks @sspeaks610 ! @bagnell what do you think?

[hpinkos]

Also reported by @craigp1231 in #6303

[ggetz]

Reported on the forum: https://groups.google.com/forum/#!topic/cesium-dev/-eSNYd_9xQk

[cesium-concierge]

Congratulations on closing the issue! I found these Cesium forum links in the comments above:

https://groups.google.com/d/msg/cesium-dev/vD3SiO5V6U8/-mMOU-bgCgAJ
https://groups.google.com/forum/#!topic/cesium-dev/-eSNYd_9xQk

If this issue affects any of these threads, please post a comment like the following:

The issue at #4122 has just been closed and may resolve your issue. Look for the change in the next stable release of Cesium or get it now in the master branch on GitHub https://github.com/AnalyticalGraphicsInc/cesium.

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[hpinkos]

@sspeaks610 @cfairchi @jeffwhitty This was just fixed and will be included in the Cesium 1.49 release available September 3rd. Thanks!