#include <math.h>
#include "vector.h"

float vlen(vector v){
  return sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
}

void vsub(vector v1, vector v2, vector result){
  int i;
  for(i = 0 ; i < 3 ; i++) result[i] = v1[i] - v2[i];
}

void vnormalise(vector v, vector result){
  float len = vlen(v);
  int i;
  for(i = 0 ; i < 3 ; i++) result[i] = v[i] / len;
}

void vcross(vector v1, vector v2, vector result){
  result[0] = v1[1] * v2[2] - v1[2] * v2[1];
  result[1] = v1[2] * v2[0] - v1[0] * v2[2];
  result[2] = v1[0] * v2[1] - v1[1] * v2[0];
}