A solemn, unsmiling, santimonious old iceberg who
looked like he was waiting for a vacancy in Trinity.
- Mark Twain

Concept 4.3 : Material - Diffuse
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Idea:
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GLfloat mat_diffuse[] = {red, green blue, alpha};
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mat_diffuse);
specifies the diffuse light reflected by an object.

Diffuse reflectance plays the most important part in what
you perceive the color of an object to be.  It is affected
by the color of the incident diffuse light and the angle of
the incident light relative to the normal direction.  The
position of the viewpoint does not affect the diffuse
reflectance at all.