Points visible through the globe when log buffer = false

[tangtony]

With v1.63, when the logarithmic depth buffer is turned off, points on the other side of the globe are visible when the camera is zoomed in.

Seems to be related to this change:
Fixed seam artifacts when log depth is disabled, scene.globe.depthTestAgainstTerrain is false, and primitives are under the globe. #8205
as if I set scene.globe.depthTestAgainstTerrain to true, the problem goes away.

Sandcastle example: https://sandcastle.cesium.com/#c=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

Browser: Chrome 78

Operating System: Windows 10

[OmarShehata]

How zoomed in do you have to be to reproduce this? I can't seem to be able to reproduce (although I am testing on Linux). Are you able to see the points through the globe on this Sandcastle ? If so, can you provide a screenshot of when it happens?

Can you also test this 1.62 Sandcastle and confirm that that one doesn't have the issue?

[tangtony]

Not too far zoomed in, here's a screenshot around New York just as the points starts to show through:

I don't have any issue reproducing it on Linux with Chrome as well. I can also reproduce with the first Sandcastle link you provided, but it's not as severe:

I can confirm 1.62 does not have the issue.

[lilleyse]

I figured out why this is happening but don't have a fix yet. The points on the opposite side of the globe are rendered in the last frustum which is past the depth plane. The same thing happened in 1.62 but the points would get overwritten by globe commands in closer frustums.

If the depth plane could be clamped to the frustum somehow this would be fixed. I can think of an elegant way involving gl_FragDepth but the depth plane should be able to work without WebGL extensions.

[simonasdmd]

@OmarShehata Is there any progress on this issue？ 8181

[lilleyse]

Fixed in #8368