15-462 Lecture 8: Shading in OpenGL

02/06/2003

15-462 Graphics I

Defining and Maintaining Normals

•Define unit normal before each vertex

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•Length changes under some transformations

•Ask OpenGL to re-normalize (all tfms)

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•Ask OpenGL to re-scale normal

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•Works for uniform scaling (and rotate, translate)

glNormal3f(nx, ny, nz);

glVertex3f(x, y, z);

glEnable(GL_NORMALIZE);

glEnable(GL_RESCALE_NORMAL);