Geometric meshes often must include surface information for lighting computations.

A normal is defined as surface normal perpendicular to the mesh. Triangular meshes imply a face normal defined by the winding order of the vertices of the triangles (typically counter-clockwise, although clock-wise winding can also be used). For efficient rendering, vertex normals are used for rendering rather than face normals.

A tangent and a bi-tangent are gradient direction vectors along the surface of a mesh. Together with the normal they describe a full 3-axis coordinate system useful for many advanced lighting techniques.



Last edited Jun 5, 2014 at 6:55 PM by walbourn, version 1