Is it a Three.js bug?

Question

I found a great three.js demo here: http://mrdoob.github.com/three.js/examples/canvas_geometry_earth.html

I noticed, that there are some line in the shadow of the earth. Is it a bug, or the author made it by design?

Answer 1

That lines are there because geometry used for shadow has an overdraw: true parameter.

That parameter is used to hide some anti-alias gaps using CanvasRenderer. It works fine for opaque textures, like the earth one, but not for transparent textures, like the shadow, because the "overdrawing" effect.

Remove parameter, or change it to false, and you can see the difference.