Update what's in global scope

scripts/geometry.js

@@ -1,6 +1,8 @@
-var Sphere = {};
-Sphere.volume = function(r) { return Math.pi*r*r*r*4/3; };
-Sphere.random = function(r,theta,phi)
+var shape = {};
+shape.sphere = {};
+shape.circle = {};
+shape.sphere.volume = function(r) { return Math.pi*r*r*r*4/3; };
+shape.sphere.random = function(r,theta,phi)
 {
   if (typeof r === 'number') r = [r,r];
   theta ??= [0,1];
@@ -18,9 +20,48 @@ Sphere.random = function(r,theta,phi)
   ];
 }
 
-var Circle = {};
-Circle.area = function(r) { return Math.pi*r*r; };
-Circle.random = function(r,theta)
+shape.circle.area = function(r) { return Math.pi*r*r; };
+shape.circle.random = function(r,theta)
 {
-  return Sphere.random(r,theta).xz;
+  return shape.sphere.random(r,theta).xz;
 }
+
+shape.box = function(w,h) {
+  w /= 2;
+  h /= 2;
+
+  var points = [
+    [w,h],
+    [-w,h],
+    [-w,-h],
+    [w,-h]
+  ];
+
+  return points;
+};
+
+shape.ngon = function(radius, n) {
+  return shape.arc(radius,360,n);
+};
+
+shape.arc = function(radius, angle, n, start) {
+  start ??= 0;
+  start = Math.deg2rad(start);
+  if (angle >= 360)
+    angle = 360;
+
+  if (n <= 1) return [];
+  var points = [];
+
+  angle = Math.deg2rad(angle);
+  var arclen = angle/n;
+  for (var i = 0; i < n; i++)
+    points.push(Vector.rotate([radius,0], start + (arclen*i)));
+
+  return points;
+};
+
+shape.circle.points = function(radius, n) {
+  if (n <= 1) return [];
+  return shape.arc(radius, 360, n);
+};