X-Git-Url: http://git.scottworley.com/nt3d/blobdiff_plain/efae2dc27628eb1c0d116b24418fc48cf48c14a3..72eac64d07af484314745fd0e9466e0f94915684:/nt3d.js?ds=inline

diff --git a/nt3d.js b/nt3d.js
index 2876698..0389946 100644
--- a/nt3d.js
+++ b/nt3d.js
@@ -259,7 +259,14 @@ nt3d = {
 		        point[2] + offset[2]];
 	},
 	angle_between: function(a, b) { // a and b must be unit vectors
-		return Math.acos(this.dot(a, b));
+		var the_dot = this.dot(a, b);
+		if (the_dot <= -1) {
+			return Math.PI;
+		}
+		if (the_dot >= 1) {
+			return 0;
+		}
+		return Math.acos(the_dot);
 	},
 	rotate_about_origin: function(points, axis, angle) { // axis must be a unit vector
 		// From http://inside.mines.edu/~gmurray/ArbitraryAxisRotation/
@@ -297,6 +304,17 @@ nt3d = {
 				angle),
 			center);
 	},
+	point_equal: function(a, b, epsilon) {
+		return Math.abs(a[0] - b[0]) < epsilon &&
+		       Math.abs(a[1] - b[1]) < epsilon &&
+		       Math.abs(a[2] - b[2]) < epsilon;
+	},
+	degenerate_face_epsilon: 1e-10,
+	is_degenerate: function(a, b, c) {
+		return this.point_equal(a, b, this.degenerate_face_epsilon) ||
+		       this.point_equal(b, c, this.degenerate_face_epsilon) ||
+		       this.point_equal(c, a, this.degenerate_face_epsilon);
+	},
 	go: function() {
 		// Remove any previous download links
 		var old_download_link = document.getElementById("nt3d_download");
@@ -318,14 +336,51 @@ nt3d = {
 
 		// Run user_function
 		this.points = this.user_function.apply(null, params);
+
+		// Do a little validation
 		if (this.points.length % 3 != 0) {
 			alert("Points list length not divisble by 3!");
 		}
-		var n = this.points.length / 3;
+		var nan_count = 0;
+		var nan_point_count = 0;
+		var nan_face_count = 0;
+		for (var i = 0; i < this.points.length/3; i++) {
+			var nan_in_face = false;
+			for (var j = 0; j < 3; j++) {
+				var nan_in_point = false;
+				for (var k = 0; k < 3; k++) {
+					if (isNaN(this.points[i*3+j][k])) {
+						nan_count++;
+						nan_in_point = true;
+						nan_in_face = true;
+					}
+				}
+				if (nan_in_point) nan_point_count ++;
+			}
+			if (nan_in_face) nan_face_count ++;
+		}
+		if (nan_count != 0) {
+			alert(nan_count + " NaNs in " + nan_point_count + " points in " + nan_face_count + " faces (" + (100 * nan_face_count / (this.points.length/3)) + "% of faces).");
+		}
+
+		// Remove degenerate faces
+		var degenerate_face_count = 0;
+		for (var i = 0; i < this.points.length/3; i++) {
+			if (this.is_degenerate(this.points[i*3+0], 
+			                       this.points[i*3+1], 
+			                       this.points[i*3+2])) {
+				this.points.splice(i*3, 3);
+				i--;
+				degenerate_face_count ++;
+			}
+		}
+		if (degenerate_face_count != 0) {
+			console.log("Removed " + degenerate_face_count + " degenerate faces");
+		}
 
 		// Make STL
 		this.stl = "solid " + this.user_function.name + "\n";
-		for (var i = 0; i < n; i++) {
+		for (var i = 0; i < this.points.length/3; i++) {
 			var a = this.points[i*3+0];
 			var b = this.points[i*3+1];
 			var c = this.points[i*3+2];