X-Git-Url: http://git.scottworley.com/nt3d/blobdiff_plain/2f6b97f8bc892064a1ca781c11b08104182f862a..aceb2da8b7e5ac5a9e5e1a994680bfff8f726209:/nt3d.js?ds=inline

diff --git a/nt3d.js b/nt3d.js
index 3d87ffb..bae29f2 100644
--- a/nt3d.js
+++ b/nt3d.js
@@ -80,31 +80,25 @@ nt3d = {
 			// loop is shape in 3d with (0,0) at path[i], shape's
 			// z axis in the direction of shapenormals[i], and
 			// shape's x axis in the direction of pathnormals[i].
-			var loop = shape;
+			// We tack [1,0,0] onto the end as a hack to see where
+			// it ends up after rotation.  This is removed later.
+			var loop = shape.concat([[1,0,0]]);
 
 			// This is done in three steps:
 			// 1. Rotate shape out of the xy plane so that [0,0,1]
-			//    becomes shapenormals[i] by crossing [0,0,1] and
-			//    shapenormals[i] to get a rotation axis and taking
-			//    their dot product to get a rotation angle.  This
-			//    puts the shape in the correct plane, but does not
-			//    constrain its rotation about shapenormals[i].
-			var rot1axis = this.unit(this.cross([0,0,1], shapenormals[i]));
-			var rot1angle = this.angle_between([0,0,1], this.unit(shapenormals[i]));
-			if (rot1angle > 1e-7) {
-				loop = this.rotate(loop, rot1axis, rot1angle);
-			}
+			//    becomes shapenormals[i].  This puts the shape in
+			//    the correct plane, but does not constrain its
+			//    rotation about shapenormals[i].
+			loop = this.rotate_onto(loop, [0,0,1], shapenormals[i]);
+			var shapex = loop.pop();
 
 			// 2. Rotate around shapenormals[i] so that [1,0,0]
 			//    becomes fixedpathnormals[i].
-			var rot2axis = this.unit(shapenormals[i]);
-			var rot2angle = this.angle_between([1,0,0], this.unit(fixedpathnormals[i]));
-			if (rot2angle > 1e-7) {
-				loop = this.rotate(loop, rot2axis, rot2angle);
-			}
-			// This would probably be faster and more numerically stable
+			loop = this.rotate_onto(loop, shapex, fixedpathnormals[i]);
+
+			// (This would probably be faster and more numerically stable
 			// if the two rotations were applied as one combined operation
-			// rather than separate steps.
+			// rather than separate steps.)
 
 			// 3. Translate to path[i].
 			loop = this.translate(loop, path[i]);
@@ -140,6 +134,9 @@ nt3d = {
 		        a[1] - b[1],
 		        a[2] - b[2]];
 	},
+	neg: function(a) {
+		return [-a[0], -a[1], -a[2]];
+	},
 	dot: function(a, b) {
 		return a[0]*b[0] + a[1]*b[1] + a[2]*b[2];
 	},
@@ -170,7 +167,7 @@ nt3d = {
 	angle_between: function(a, b) { // a and b must be unit vectors
 		return Math.acos(this.dot(a, b));
 	},
-	rotate: function(points, axis, angle) { // axis must be a unit vector
+	rotate_about_origin: function(points, axis, angle) { // axis must be a unit vector
 		// From http://inside.mines.edu/~gmurray/ArbitraryAxisRotation/
 		var cosangle = Math.cos(angle);
 		var sinangle = Math.sin(angle);
@@ -185,11 +182,44 @@ nt3d = {
 		}
 		return rotated;
 	},
+	rotate_onto: function(points, a, b) {
+		// Rotate points such that a (in points-space) maps onto b
+		// by crossing a and b to get a rotation axis and using
+		// angle_between to get a rotation angle.
+		var angle = this.angle_between(this.unit(a), this.unit(b));
+		if (Math.abs(angle) < 1e-15) {
+			// No siginificant rotation to perform.  Bail to avoid
+			// NaNs and numerical error
+			return points;
+		}
+		var axis = this.unit(this.cross(a, b));
+		return this.rotate_about_origin(points, axis, angle);
+	},
+	rotate: function(points, center, axis, angle) { // axis must be a unit vector
+		return this.translate(
+			this.rotate_about_origin(
+				this.translate(points, this.neg(center)),
+				axis,
+				angle),
+			center);
+	},
 	go: function() {
+		// Remove any previous download links
+		var old_download_link = document.getElementById("nt3d_download");
+		if (old_download_link) {
+			old_download_link.parentNode.removeChild(old_download_link);
+		}
+
+		// Continue in a callback, so that there's not a stale download
+		// link hanging around while we process.
+		setTimeout(function(the_this) { (function() {
+
 		// Get params from form
 		var params = [];
 		for (var i = 0; i < this.user_params.length; i++) {
-			params[i] = this.form.elements["param"+i].value;
+			var as_string = this.form.elements["param"+i].value;
+			var as_num = +as_string;
+			params[i] = isNaN(as_num) ? as_string : as_num;
 		}
 
 		// Run user_function
@@ -216,11 +246,6 @@ nt3d = {
 		}
 		this.stl += "endsolid " + this.user_function.name + "\n";
 
-		// Remove any previous download links
-		var old_download_link = document.getElementById("nt3d_download");
-		if (old_download_link) {
-			old_download_link.parentNode.removeChild(old_download_link);
-		}
 
 		// Offer result as download
 		var download_link = document.createElement("a");
@@ -231,6 +256,8 @@ nt3d = {
 		download_link.setAttribute("href", "data:application/sla," + encodeURIComponent(this.stl));
 		this.ui.appendChild(download_link);
 		setTimeout(function() { download_link.setAttribute("style", "-webkit-transition: background-color 0.4s; -moz-transition: background-color 0.4s; -o-transition: background-color 0.4s; -ms-transition: background-color 0.4s; transition: background-color 0.4s; background-color: inherit"); }, 0);
+
+		}).call(the_this); }, 0, this); // (We were in a callback this whole time, remember?)
 	},
 	framework: function (f, params) {
 		this.user_function = f;