z-fighting in fill-extrusion buildings

[akoylasar]

Some of the buildings in the fill-extrusion layer manifest a z-fighting artifact as seen in the video below:

zfight_in_fill_extrusion.mp4

Steps to Trigger Behavior

1. Add a fill extrusion layer with fill-extrusion-ambient-occlusion-intensity = 0.5 and fill-extrusion-ambient-occlusion-radius = 3.
2. Navigate to 17.49/60.171903/24.943105/-88.1/75

Observe the artifact manifesting itself on one of the buildings as panning/zooming around.

cc @mapbox/gl-native @astojilj

[dagjomar]

I experience the same behaviour when adding a thin rectangle outside of a bigger rectangle. The bigger extruded rectangle will win the z-fighting and show it's face with ambient occlusion, while the thinner extruded rectangle will be hidden, even though it is closer to the camera