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

float MathUtils::distance(float x1, float y1, float z1,
			  float x2, float y2, float z2)
{
    float dx = x2 - x1;
    float dy = y2 - y1;
    float dz = z2 - z1;
    return sqrt(dx*dx + dy*dy + dz*dz);
}

// Algorithm found at http://paulbourke.net/geometry/lineline2d/
bool MathUtils::lines_intersect(int x1, int y1, int x2, int y2,
				int x3, int y3, int x4, int y4)
{
    int denom = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);

    int a = (x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3);
    int b = (x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3);

    if (denom == 0) return false;

    float ua = (float)a / denom;
    float ub = (float)b / denom;

    return ua > 0 && ua < 1 && ub > 0 && ub < 1;
}