camera angle affects lighting

[Keith W. <kw...@cs...>]

Has anyone ever noticed that the camera angle can affect the apparent
illuimation of surfaces?  As I rotate the camera, the brightness of a
surface changes even though that surface's location in global space, and
with respect to the environmental lights never changes.  I can observe
this effect with a null shader, or lambert or phong.  All three do it.  I
think I am only seeing it with alpha-layer 32 bit textures, so it might
have something to do with the way lower layers are combined with higher
layers to produce a projected pixel value.

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Keith Wiley                                kw...@cs...
http://www.unm.edu/~keithw                 http://www.mp3.com/KeithWiley

"Yet mark his perfect self-contentment, and hence learn his lesson,
that to be self-contented is to be vile and ignorant, and that to
aspire is better than to be blindly and impotently happy."
                                           --  Edwin A. Abbott, Flatland
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