X-Git-Url: http://git.scottworley.com/nt3d/blobdiff_plain/08c25ec8473e43e82a1291a528f8332239581483..20ba9ac85c5721d6dda7b1e8a3e97089a52461c4:/nt3d.js

diff --git a/nt3d.js b/nt3d.js
index 9b09b09..62d898e 100644
--- a/nt3d.js
+++ b/nt3d.js
@@ -62,6 +62,35 @@ nt3d = {
 		return this.closed_trianglefan([apex].concat(base)).concat(
 		       this.trianglefan(base.reverse()));
 	},
+	shapenormals_from_closed_path: function(path) {
+		return function(i) {
+			var prev = (i == 0) ? path.length-1 : i-1;
+			var next = (i == path.length-1) ? 0 : i+1;
+			return nt3d.sub(path[next], path[prev]);
+		};
+	},
+	shapenormals_from_path_and_extra_points: function(path, first_point, last_point) {
+		return function(i) {
+			var prev = (i == 0) ? first_point : path[i-1];
+			var next = (i == path.length-1) ? last_point : path[i+1];
+			return nt3d.sub(next, prev);
+		};
+	},
+	shapenormals_from_path_and_first_and_last_normals: function(path, first_normal, last_normal) {
+		return function(i) {
+			if (i == 0) { return first_normal; }
+			if (i == path.length-1) { return last_normal; }
+			return nt3d.sub(path[i+1], path[i-1]);
+		};
+	},
+	pathnormals_from_point: function(path, p) {
+		// Use this with any point that is not on any path tangent line
+		var pathnormals = [];
+		for (var i = 0; i < path.length; i++) {
+			pathnormals.push(this.sub(path[i], p));
+		}
+		return pathnormals;
+	},
 	to_function: function(thing, make_indexer) {
 		// If thing is a point, just yield thing every time.
 		// If thing is a list of points && make_indexer, index into thing.
@@ -77,19 +106,19 @@ nt3d = {
 	},
 	extrude: function(path, shape, shapenormals, pathnormals) {
 
-		var guts_result = nt3d._extrude_guts(path, shape, shapenormals, pathnormals);
+		var guts_result = this._extrude_guts(path, shape, shapenormals, pathnormals);
 		// Add the end-caps
 		// XXX: This doesn't work if shape is not convex
 		return guts_result.points.concat(
-			nt3d.trianglefan(guts_result.first_loop.reverse()),
-			nt3d.trianglefan(guts_result.last_loop));
+			this.trianglefan(guts_result.first_loop.reverse()),
+			this.trianglefan(guts_result.last_loop));
 
 	},
 	closed_extrude: function(path, shape, shapenormals, pathnormals) {
-		var guts_result = nt3d._extrude_guts(path, shape, shapenormals, pathnormals);
+		var guts_result = this._extrude_guts(path, shape, shapenormals, pathnormals);
 		// Stitch the ends together
 		return guts_result.points.concat(
-			nt3d.closed_quadstrip(nt3d.zip(guts_result.first_loop, guts_result.last_loop)));
+			this.closed_quadstrip(this.zip(guts_result.first_loop, guts_result.last_loop)));
 	},
 	_extrude_guts: function(path, shape, shapenormals, pathnormals) {
 		var shape_fun = this.to_function(shape, false);
@@ -143,7 +172,7 @@ nt3d = {
 			if (i == 0) {
 				result.first_loop = loop;
 			} else {
-				result.points = result.points.concat(nt3d.closed_quadstrip(nt3d.zip(loop, prev_loop)));
+				result.points = result.points.concat(this.closed_quadstrip(this.zip(loop, prev_loop)));
 			}
 			prev_loop = loop;
 		}
@@ -190,7 +219,7 @@ nt3d = {
 	},
 	project: function(a, b) { // Project b onto a
 		var a_magnitude = this.magnitude(a);
-		return this.scale(a, this.dot(a, b) / a_magnitude * a_magnitude);
+		return this.scale(a, this.dot(a, b) / (a_magnitude * a_magnitude));
 	},
 	project_to_orthogonal: function(a, b) {
 		// The nearest thing to b that is orthogonal to a