Point always visible through other objects in `ThreeDScene` when using Cairo

[hennels]

Description of bug / unexpected behavior

Point objects are always visible when in a ThreeDScene, even when they should be occluded by other objects.

Expected behavior

If a point is behind or inside another object it should not be visible. Just like in a 2D scene.

How to reproduce the issue

Place a Point in a ThreeDScene behind or inside another object. Here I have placed a point inside a cube and it is still visible.

Code for reproducing the problem

class PointInsideCube(ThreeDScene):
    def construct(self):
        self.add(Point(color=BLACK))
        self.add(Cube(side_length=2, fill_opacity=1.0))
        self.wait(1)

If the `ThreeDScene` in the above example is replaced with `Scene` the desired behavior is achieved.

Additional media files

Frame using `ThreeDScene`

Frame using `Scene`

Additional comments

I don't know if this is expected behavior for ThreeDScene but it doesn't seem right to me. I tried the shade_in_3d=True keyword argument that is listed in #2032 but Point does not accept it and it has no effect on Cube. Am I missing something else?

[hennels]

This only seems to happen when using the Cairo renderer. If I switch to OpenGL the occlusion is respected and the point is not visible.