Update

www/js/p5_custom.js

@@ -0,0 +1,15 @@
+
+draw_arrow=function(p,x1,y1,x2,y2){
+    p.push()
+    p.strokeWeight(5)
+    p.line(x1,y1,x2,y2)
+    offset=5
+    var angle = p.atan2(y1 - y2, x1 - x2); //gets the angle of the line
+    p.translate(x2, y2); //translates to the destination vertex
+    p.rotate(angle-p.HALF_PI); //rotates the arrow point
+    p.triangle(-offset*0.8, offset, offset*0.8, offset, 0, -offset/2); //draws the arrow point as a triangle
+    p.pop();
+
+    // Return the center of the arrow
+    return(p.createVector(x1+(x2-x1)/2,y1+(y2-y1)/2))
+}