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View Full Version : GL_TRIANGLE_STRIP and Normals



jleffelm
01-06-2004, 09:39 AM
How does one go about setting up normals for a triangle strip? For example, if I am creating four faces of a cube using a triangle strip, The vertices could have two different normals(one for each of the faces it is a part of). Should I just average them, or should I create seperate faces as separate triangle strips? How is this taken care of? Thanks for the help.

-Drew

JanHH
01-06-2004, 12:20 PM
in a triangle strip, a vertex that is part of several triangles is only specified once (that is the sense of triangle strips) and as only one normal. There is no way of giving a vertex that several triangles inside of a strip share separate normals for each face. If you need this, these faces simply cannot be inside of the same triangle strip. Same of course is for texture coordinates.

This, I guess, is the reason why triangle strips are not very much supported in 3d model formats.

Jan

jleffelm
01-06-2004, 12:37 PM
Thanks. I was afraid of that. http://www.opengl.org/discussion_boards/ubb/frown.gif