Vector Math

class Vec4

This class implements a 4-dimensional real-valued vector. Individual elements are represent with double precision floating point numbers. To use the Vec4 class you must include the header

    #include <gfx/vec4.h>

Constructor Methods

The Vec4 class defines the following set of constructors:

    Vec4();                                        // Initializes vector to (0 0 0 0).
    Vec4(double x, double y, double z, double w);  // Initializes vector to (x y z w).
    Vec3(double s);                                // Initializes vector to (s s s s)

    Vec4(const Vec4& v);                           // 
    Vec4(const float  v[4]);                       // These copy values from v
    Vec4(const double v[4]);                       // 

    Vec4(const Vec3& v, double w);                 // Initializes vector to (v[0] v[1] v[2] w)

Specialized Functions

In addition to the standard functions provided by all vector classes, the Vec4 class defines certain specialized functions which operate only on 4-D vectors.

The cross product of three 4-vectors u, v, w is a fourth vector which is perpendicular to all of u, v, w. It can be computed with the function call

    t = cross(u, v, w);

Since 4-D vectors are frequently used to represent 3-D homogeneous coordinates, a projection function is provided.

    Vec3 proj(const Vec4& v);