TEXMAP extension thoughts and findings.

[Roland Melkert]

Furthermore, the spec doesn't say in which direction the arctangents are computed (i.e., does the image appear in its natural orientation as viewed from the outside of the cylinder, or from the inside?)

I assumed, as the result of the LDraw orientation of up=-y, textures should use top/left orientation for uv at the level texmap is at.

The spec is even less clear about spherical textures, as it doesn't say whether the third control point corresponds to the "left" or the "right" side of the texture. In my implementation I've been (somewhat arbitrarily) assuming that it goes on the right.

I too used right, thinking the p1,p2,p3 triangle is to be used CCW when calculating the sphere up vector.