Vector Math

class Vec3

This class implements a 3-dimensional real-valued vector. Individual elements are represent with double precision floating point numbers. To use the Vec3 class you must include the header

    #include <gfx/vec3.h>

Constructor Methods

The Vec3 class defines the following set of constructors:

    Vec3();                              // Initializes vector to (0 0 0).
    Vec3(double x, double y, double z);  // Initializes vector to (x y z).
    Vec3(double s);                      // Initializes vector to (s s s)

    Vec3(const Vec3& v);                 // 
    Vec3(const float  v[3]);             // These copy values from v
    Vec3(const double v[3]);             // 

    Vec3(const Vec2& v, double z);       // Initializes vector to (v[0] v[1] z)

Specialized Functions

In addition to the standard functions provided by all vector classes, the Vec3 class defines certain specialized functions which operate only on 3-D vectors.

The cross product of two vectors v, w is a third vector which is perpendicular to both v and w. It can be computed with either a function call or an overloaded operator

    u = cross(v, w);   // Equivalent ways of computing
    u = v ^ w;         //    the cross product of v and w.

Since 3-D vectors may be used to represent 2-D homogeneous coordinates, a projection function is provided.

    Vec2 proj(const Vec3& v);
This routine takes a homogeneous vector (x y w) and returns the corresponding 2-D vector (x/w y/w). If w is 0 then the vector (x y) is returned.