2018-soft-3d-renderer/src/vec.cpp

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


void VectorNormalize(Vector &v)
{
    float length = VectorLength(v);

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

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

float VectorLength(Vector &v)
{
    float result = sqrtf(v.x * v.x + v.y * v.y + v.z * v.z);

    // zero length
    if (result < EPSILON_E3)
    {
        result = 0.0f;
    }

    return result;
}

float VectorDot(Vector &v1, Vector &v2)
{
    float result;

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

    return result;
}

Vector VectorCross(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;
}