1 files changed, 17 insertions, 0 deletions
diff --git a/balls.h b/balls.h
index b69eea4..1a0038b 100644
--- a/balls.h
+++ b/balls.h
@@ -19,13 +19,30 @@ typedef struct {
 	double m; /* mass [kg] */
 } Ball;
 
+Point addPt(Point p, Point q);
+Point subPt(Point p, Point q);
 Point ptAddVec(Point p, Vector v);
+Point ptSubVec(Point p, Vector v);
+Point ptMulS(Point p, double s);
+Point ptDivS(Point p, double s);
 Point Pt(double x, double y);
+
+Vector addVec(Vector v1, Vector v2);
+Vector subVec(Vector v1, Vector v2);
+Vector vecMulS(Vector v, double s);
+Vector vecDivS(Vector v, double s);
+double vecDot(Vector v1, Vector v2);
+Vector unitNorm(Vector v);
+double vecLen(Vector v);
+Vector Vec(double x, double y);
+Vector VecPt(Point p, Point q);
+
 Rectangle insetRect(Rectangle r, double n);
 Point randPtInRect(Rectangle r);
 
 int isCollision(Point p1, double r1, Point p2, double r2);
 void collideWall(Ball *b, Rectangle wall);
+void collideBall(Ball *b1, Ball *b2);
 
 int randInt(int lo, int hi);
 double randDouble(double lo, double hi);