If the current matrix is $C$, and the coordinates to be transformed are, $v ~=~ (v[0], v[1], v[2], v[3])$. Then the current transformation is $C ~times~ v$, or
down 130 {{ left ( matrix { ccol { c[0] above c[1] above c[2] above c[3] } ccol { c[4] above c[5] above c[6] above c[7] } ccol { c[8] above c[9] above c[10] above c[11] } ccol { c[12]~ above c[13]~ above c[14]~ above c[15]~ } } right ) } ~~ times ~~ {left ( matrix { ccol { v[0]~ above v[1]~ above v[2]~ above v[3]~ } } right )} }
Calling
glMultMatrix with an argument of $"m" ~=~ m[0], m[1], ..., m[15]$ replaces the current transformation with $(C ~times~ M) ~times~ v$, or
down 130 {{ left ( matrix { ccol { c[0] above c[1] above c[2] above c[3] } ccol { c[4] above c[5] above c[6] above c[7] } ccol { c[8] above c[9] above c[10] above c[11] } ccol { c[12]~ above c[13]~ above c[14]~ above c[15]~ } } right ) } ~~ times ~~ { left ( matrix { ccol { m[0] above m[1] above m[2] above m[3] } ccol { m[4] above m[5] above m[6] above m[7] } ccol { m[8] above m[9] above m[10] above m[11] } ccol { m[12]~ above m[13]~ above m[14]~ above m[15]~ } } right ) } ~~ times ~~ {left ( matrix { ccol { v[0]~ above v[1]~ above v[2]~ above v[3]~ } } right )} }
Where '$times$' denotes matrix multiplication, and $v$ is represented as a $4 ~times~ 1$ matrix.