Guidelines for API design

• Output() operations must be idempotent: regardless of how many times it is executed, the initial result must not change if no parameters have changed since.

• 2D primitives should be constructed in the XZ plane, with the face and vertex normals pointing upwards along the Y axis. Looking from above, the vertices should be indexed in clockwise order starting at the positive X axis. Likewise, the triangle faces should constructed in clockwise order so the face normals point upwards.