I was just curious about this one.

From the Redbook, pg 206 (2nd ed):
“Contributions from Light Sources
Each light source may contribute to a
vertex’s color, and these contributions
are added together.”

I assume the addition is so that each light can be applied to the vertex in turn without regard to the previous light.

Is there a reason why some kind of compare-exchange logic could not be employed, such that only the most intense R,G, & B contributions were applied to a vertex?

I’m obviously still learning about the OpenGL pipeline & underlying hardware, so any explanations are welcome.

– Jeff