2018-soft-3d-renderer/include/vec.h

#ifndef VEC_H

#include "util.h"
#include <cmath>


// STRUCTURE
struct Vector
{
    inline Vector(void) : x(0), y(0), z(0), w(0) {}
    inline Vector(float x, float y, float z) : x(x), y(y), z(z), w(0) {}

    inline void Normalize(void)
    {
        float length = sqrtf(x*x + y*y + z*z);

        // zero length
        if (length < EPSILON_E3)
        {
            x = 0.0f;
            y = 0.0f;
            z = 0.0f;
        }
        else
        {
            float lengthInv = 1.0f / length;

            x *= lengthInv;
            y *= lengthInv;
            z *= lengthInv;
        }
    }

    inline static float Dot(Vector v1, Vector v2)
    {
        float result;

        result = (v1.x * v2.x) + (v1.y * v2.y) + (v1.z * v2.z);

        return result;
    }

    inline static Vector Cross(Vector v1, Vector v2)
    {
        Vector result;

        result.x = (v1.y * v2.z) - (v1.z * v2.y);
        result.y = (v1.z * v2.x) - (v1.x * v2.z);
        result.z = (v1.x * v2.y) - (v1.y * v2.x);

        return result;
    }

    union
    {
        float e[4];

        struct
        {
            float x, y, z, w;
        };
    };
};


// OPERATORS
// -v
inline Vector operator-(Vector v)
{
    Vector result;

    result.x = -v.x;
    result.y = -v.y;
    result.z = -v.z;

    return result;
}

// v1 + v2
inline Vector operator+(Vector v1, Vector v2)
{
    Vector result;

    result.x = v1.x + v2.x;
    result.y = v1.y + v2.y;
    result.z = v1.z + v2.z;

    return result;
}

// v1 += v2
inline Vector &operator+=(Vector &v1, Vector v2)
{
    v1 = v1 + v2;

    return v1;
}

// v / f
inline Vector operator/(Vector v, float f)
{
    Vector result;

    float inverse = 1.0f / f;

    result.x = v.x * inverse;
    result.y = v.y * inverse;
    result.z = v.z * inverse;

    return result;
}

// v /= f
inline Vector &operator/=(Vector &v, float f)
{
    v = v / f;

    return v;
}


#define VEC_H
#endif