Mathematical Topics from 3D Graphics - 3D Math Primer for Graphics and Game Development - page 388

Figure 10.13. Approximating cylinders with prisms of varying number of sides.

s t r u c t V e r t e x {

V e c t o r 3 po s ;

V e c t o r 3 n o r m a l ;

} ;
s t r u c t T r i a n g l e {

i n t v e r t e x I n d e x [ 3 ] ;

V e c t o r 3 n o r m a l ;

} ;
s t r u c t

{

T r i a n g l e M e s h

i n t v e r t e x C o u n t ;

V e r t e x ∗ v e r t e x L i s t ;

i n t t r i a n g l e C o u n t ;

T r i a n g l e ∗ t r i a n g l e L i s t ;

v o i d c o m p u t e V e r t e x N o r m a l s ( ) {

/ / F i r s t c l e a r o u t t h e v e r t e x n o r m a l s

f o r ( i n t i = 0 ; i < v e r t e x C o u n t ; ++ i ) {

v e r t e x L i s t [ i ] . n o r m a l . z e r o ( ) ;

}

/ / Now add i n t h e f a c e n o r m a l s i n t o t h e

/ / n o r m a l s o f t h e a d j a c e n t v e r t i c e s

f o r ( i n t i = 0 ; i < t r i a n g l e C o u n t ; ++ i ) {