Ray-Line intersection solver

static inline int bet(float a, float m, float b){
	return fabs(a - m) + fabs(m - b) == fabs(a - b);
}

typedef float vec2[2];
typedef struct{
	vec2 p;
	vec2 n;
} ray2;
static inline void vec2_add(vec2 r, vec2 a, vec2 b){
	int i;
	for(i=2;i--;){
		r[i] = a[i] + b[i];
	}
}
static inline void vec2_sub(vec2 r, vec2 a, vec2 b){
	int i;
	for(i=2;i--;){
		r[i] = a[i] - b[i];
	}
}

/*
	y = m1x + b1	y = m2x + b2

	m1x + b1 = m2x + b2
	m1x = m2x + b2 - b1
	x(m1 - m2) = b2 - b1
	x = (b2 - b1) / (m1 - m2)
*/
static inline int vec2_ray_line(vec2 itrsec, ray2 ray, vec2 v1, vec2 v2){
	float m_ray  = ray.n[1] / ray.n[0];
	float m_line_rise = v2[1] - v1[1], m_line_run = v2[0] - v1[0];
	float m_line = (m_line_rise) / (m_line_run == 0 ? 0.1f : m_line_run);
	float yint_ray = (-ray.p[0] * m_ray) + ray.p[1], yint_line = (-v1[0] * m_line) + v1[1];
	float x = (yint_line - yint_ray) / (m_ray - m_line);
	float dy1, dy2, dv12;
	float sx, sy;

	itrsec[0] = x;
	itrsec[1] = x * m_ray + yint_ray;

	dy1  = fabs(v1[1] - itrsec[1]);
	dy2  = fabs(itrsec[1] - v2[1]);
	dv12 = fabs(v1[1] - v2[1]);

	sx = (itrsec[0] - ray.p[0]) / ray.n[0];
	sy = (itrsec[1] - ray.p[1]) / ray.n[1];

	return (bet(v1[0], itrsec[0], v2[0]) || bet(v1[1], itrsec[1], v2[1])) && (sx >= 0 || sy >= 0);
}