View Full Version : GL Redbook Question

03-14-2002, 04:56 PM

I have a question about the section in the OpenGL Redbook that is titled "The Mathematics of Lighting". In this section they show the calculation for the specular component of a light to be as follows:

(max {s n, 0})shininess * specularlight * specularmaterial

Did they forget to put a * inbetween max of the dot product of s & n and the shininess variable to show that the values are multiplied? I noticed that for the diffuse calculation the max is multiplied by the material and diffuse light values. Is it the same for this and they just forgot to put in the *, or does this mean something else? I just want to be sure because I'm going to need to use this calculation.


03-14-2002, 11:14 PM
I've just had a quick look and you'll notice that the term shininess is written above the line ie. in suprscript. Thus the calculation is 'to the power' not 'multiply':

(max{s.n, 0})^shininess * specularlight * specularmaterial


[This message has been edited by thelamberto (edited 03-15-2002).]

03-15-2002, 08:34 AM
Ok thanks, that makes sense. But I do not see that, it is at the same level on the line in my browswer (I tried netscape & IE 5.0) Are you talking about the actual OpenGL Red Book? I meant the online version in opengl.org's documentation section. I'll have to find a copy of the Red Book and see if it is different. Thanks