Rings alternate twirl directions

[nt3d] / medusa.html

diff --git a/medusa.html b/medusa.html
index 17181cce5113e57c986faabe7520718d256954f0..7a4babd9e69a8eaca8940dd1a4c998c694e6f091 100644 (file)
--- a/medusa.html
+++ b/medusa.html
@@ -3,10 +3,12 @@
     <title>Medusa</title>
     <script type="text/javascript" src="nt3d.js"></script>
     <script type="text/javascript">
-      function finger(params, finger_crosssection, ring_radius, finger_angle) {
+      function finger(params, finger_crosssection, ring_num, ring_radius, finger_angle) {
         var path = [];
+        var twirl_amplitute = Math.cos((ring_num * 2 * Math.PI) / params.finger_twirl_period);
+        var twirl_angle = twirl_amplitute * params.finger_twirl_distance / (ring_radius * 2 * Math.PI);
         for (var finger_point = 0; finger_point <= params.finger_points; finger_point++) {
-          var angle = (finger_angle + params.finger_twirl * finger_point / params.finger_points) * 2 * Math.PI;
+          var angle = (finger_angle + twirl_angle * finger_point / params.finger_points) * 2 * Math.PI;
           var x = ring_radius * Math.cos(angle);
           var y = ring_radius * Math.sin(angle);
           path.push([x, y, params.finger_height * finger_point / params.finger_points]);
@@ -18,22 +20,24 @@
         var fingers = [];
         for (var ring_num = 0; ring_num < params.num_rings; ring_num++) {
           var ring_radius = params.first_ring_radius + ring_num * params.ring_spacing;
-          for (var finger_num = 0; finger_num < params.num_fingers; finger_num++) {
-            var finger_angle = finger_num / params.num_fingers;
-            fingers = fingers.concat(finger(params, finger_crosssection, ring_radius, finger_angle));
+          var num_fingers = Math.round((ring_radius * 2 * Math.PI) / params.finger_spacing);
+          for (var finger_num = 0; finger_num < num_fingers; finger_num++) {
+            var finger_angle = finger_num / num_fingers;
+            fingers = fingers.concat(finger(params, finger_crosssection, ring_num, ring_radius, finger_angle));
           }
         }
 
         return fingers;
       }
       var params = [["first_ring_radius", 20],
-                    ["num_rings", 10],
+                    ["num_rings", 4],
                     ["ring_spacing", 10, "Space Between Rings"],
-                    ["num_fingers", 5],
+                    ["finger_spacing", 10],
                     ["finger_radius", 3],
-                    ["finger_faces", 5],
+                    ["finger_faces", 3],
                     ["finger_points", 20],
-                    ["finger_twirl", .1, "Finger Twirl (in turns)"],
+                    ["finger_twirl_distance", 50],
+                    ["finger_twirl_period", 2, "Finger Twirl Period (1=same, 2=alternating)"],
                     ["finger_height", 100]];
     </script>
   </head>