+<html>
+ <head>
+ <title>Wrap Sphere</title>
+ <script type="text/javascript" src="nt3d.js"></script>
+ <script type="text/javascript">
+ function wrap_sphere(sphere_radius, extrusion_radius, turns, circle_angle, aspect_ratio, distortion_angle, steps_around, steps_along) {
+ // Spiral path along sphere surface
+ var path = [];
+ for (var i = 0; i < steps_along; i++) {
+ var progress_0to2 = i / (steps_along/2);
+ var progress_0to1andback = progress_0to2 < 1 ? progress_0to2 : 2 - progress_0to2;
+ var progress_neg1to1andback = progress_0to1andback * 2 - 1;
+ var z = progress_neg1to1andback * sphere_radius;
+ var r = Math.sqrt(sphere_radius*sphere_radius - z*z);
+ var phase_adjust = progress_0to2 < 1 ? 0 : Math.PI;
+ var x = r*Math.cos(progress_0to1andback*turns*2*Math.PI + phase_adjust);
+ var y = r*Math.sin(progress_0to1andback*turns*2*Math.PI + phase_adjust);
+ path.push([x,y,z]);
+ }
+
+ // Shape to be extruded
+ var shape = nt3d.circle(extrusion_radius, steps_around);
+ shape = nt3d.rotate_about_origin(shape, [0,0,1], circle_angle*Math.PI*2);
+ for (var i = 0; i < shape.length; i++) {
+ shape[i][0] *= aspect_ratio;
+ }
+ shape = nt3d.rotate_about_origin(shape, [0,0,1], distortion_angle*Math.PI*2);
+
+ return nt3d.closed_extrude(
+ path,
+ shape,
+ nt3d.shapenormals_from_closed_path(path),
+ nt3d.pathnormals_from_point(path, [0, 0, 0]));
+ }
+ var params = [["Sphere radius", 100],
+ ["Extrusion radius", 5],
+ ["Turns", 3],
+ ["Angle of circle (in turns) (useful when steps_around is small)", .125],
+ ["Aspect ratio", 2],
+ ["Angle of distortion (in turns)", .25],
+ ["Steps around", 4],
+ ["Steps along", 500]];
+ </script>
+ </head>
+ <body onload="nt3d.framework(wrap_sphere, params)">
+ <h1>Wrap Sphere</h1>
+ <p>Extrude something in a spiral along the surface of a sphere.</p>
+ </body>
+</html>
projects / nt3d / commitdiff