The description of the gluLookAt is as follows:
Let
F=centerX-eyeXcenterY-eyeYcenterZ-eyeZ
Let UP be the vector upXupYupZ.
Then normalize as follows:
f=FF
UP″=UPUP
Finally, let s=fUP″, and u=sf.
M is then constructed as follows:
M=s⁡0s⁡1s⁡20u⁡0u⁡1u⁡20-f⁡0-f⁡1-f⁡200001 //??????
gluLookAt is equivalent to
glMultMatrixf(M);
glTranslated(-eyex, -eyey, -eyez);



Can you explain the description above?Especially the define of M,the line with ????.
Thank you very much.