3d - What is the normal of a face? -

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i told normal of face 'a vector perpendicular face' still don't when trying draw 3d shapes. give me clearer explanation, or (even better) diagram? chunk of code confuses me call glnormal3f(x, y, z).

a quick google , can find tutorial, includes following diagram:

opengl

as can see, normals directional vectors perpendicular face. used in lighting calculations can correct shading displayed when have directional lighting.


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