The red logo has an eyeOffset.z = -1e6 , and the red billboard disappears when the camera height is below 1e6. However, why does the yellow logo with eyeOffset.z = 1e6 disappear at the same time?
the red billboard disappears when the camera height is below 1e6
No. The eyeOffset works in eye coordinates, that means that the z coordinate rather measures the distance between the object and the camera instead of the camera height to the earth.
That is why, when zooming in, the yellow billboards disappear before the red billboards disappear.
I want the red billboard to always be displayed above the yellow billboard , and I want both the red and yellow billboards to remain visible regardless of the zoom level or perspective. How can I achieve this?
You can set disableDepthTestDistance: Number.POSITIVE_INFINITY on the red billboards (instead of the eyeOffset) so that they are always drawn above anything else. Unfortunately, this also means that the rendering order of the red billboards decides the overlapping between red billboards, i.e., it’s possible that red billboards that are further away are drawn above red billboards that are close to the camera.
So basically, what you want is a working depth test between the red billboards, but a disabled depth test when a red billboard is compared to non-red billboards? I don’t know how to do that, maybe others can chime in…
