http://xyst.i2p/DEBUG/cppcheck/57.html
\return Triangle area inline real normal ( real x1 , real x2 , real x3 , real y1 , real y2 , real y3 , real z1 , real z2 , real z3 , real & nx , real & ny , real & nz ) { real ax = x2 - x1 ; real ay = y2 - y1 ; real az = z2 - z1 ; real bx = x3 - x1 ; real by = y3 - y1 ; real bz = z3 - z1 ; real n1 = ay * bz - az * by ; real n2 = - ( ax * bz - az * bx ); real n3 = ax * by - ay * bx ; auto farea = std :: sqrt ( n1 * n1 + n2 * n2 + n3 * n3 ); nx = n1 / farea...