1 files changed, 95 insertions, 0 deletions
diff --git a/geometry.cpp b/geometry.cpp
index 2bdad8c..542c08d 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -1,6 +1,22 @@
+#include <math.h>
+
 #include "balls.h"
 
 Point
+addPt(Point p, Point q) {
+	p.x += q.x;
+	p.y += q.y;
+	return p;
+}
+
+Point
+subPt(Point p, Point q) {
+	p.x -= q.x;
+	p.y -=q.y;
+	return p;
+}
+
+Point
 ptAddVec(Point p, Vector v) {
 	p.x += v.x;
 	p.y += v.y;
@@ -8,11 +24,90 @@ ptAddVec(Point p, Vector v) {
 }
 
 Point
+ptSubVec(Point p, Vector v) {
+	p.x -= v.x;
+	p.y -= v.y;
+	return p;
+}
+
+Point
+ptMulS(Point p, double s) {
+	p.x *= s;
+	p.y *= s;
+	return p;
+}
+
+Point
+ptDivS(Point p, double s) {
+	p.x /= s;
+	p.y /=s;
+	return p;
+}
+
+Point
 Pt(double x, double y) {
 	Point p = {x, y};
 	return p;
 }
 
+Vector
+addVec(Vector v1, Vector v2) {
+	v1.x += v2.x;
+	v1.y += v2.y;
+	return v1;
+}
+
+Vector
+subVec(Vector v1, Vector v2) {
+	v1.x -= v2.x;
+	v1.y -= v2.y;
+	return v1;
+}
+
+Vector
+vecMulS(Vector v, double s) {
+	v.x *= s;
+	v.y *= s;
+	return v;
+}
+
+Vector
+vecDivS(Vector v, double s) {
+	v.x /= s;
+	v.y /= s;
+	return v;
+}
+
+double
+vecDot(Vector v1, Vector v2) {
+	return v1.x*v2.x + v1.y*v2.y;
+}
+
+Vector
+unitNorm(Vector v) {
+	return vecDivS(v, vecLen(v));
+}
+
+double
+vecLen(Vector v) {
+	return sqrt(v.x*v.x + v.y*v.y);
+}
+
+Vector
+Vec(double x, double y) {
+	Vector v = {x, y};
+	return v;
+}
+
+Vector
+VecPt(Point p, Point q) {
+	double dx, dy;
+
+	dx = q.x - p.x;
+	dy = q.y - p.y;
+	return Vec(dx, dy);
+}
+
 Rectangle
 insetRect(Rectangle r, double n) {
 	r.min.x += n;