2d cartesian and polar coordinate header

[Aereshaa]

This is a header and library I use in a lot of my games. It used to be larger, but I have cut it down over a few months to the tasks I use the most.

point.h

typedef struct point_ {float x, y;} point;
typedef struct vector_ {float th, r;} vector;

vector mkvec(float th, float r);
point mkpnt(float x, float y);
vector pnt2vec(point p);
point vec2pnt(vector v);
point pntadd(point p, point q);
point pntsub(point p, point q);

extern point pnt_z;

point.c

#include "point.h"
#include "math.h"

vector mkvec(float th, float r){
	vector v;
	v.th = th;
	v.r = r;
	return v;	
}

point mkpnt(float x, float y){
	point p;
	p.x = x;
	p.y = y;
	return p;
}

vector pnt2vec(point p){
	return mkvec(atan2(p.y, p.x), sqrt(p.x * p.x + p.y * p.y));
}

point vec2pnt(vector v){
	return mkpnt(v.r * cos(v.th), v.r * sin(v.th));
}

point pntadd(point p, point q){
	p.x += q.x;
	p.y += q.y;
	return p;
}

point pntsub(point p, point q){
	p.x -= q.x;
	p.y -= q.y;
	return p;
}
	
point pnt_z = {0.0,0.0};