A helper function for generating pathnormals

[nt3d] / nt3d.js

diff --git a/nt3d.js b/nt3d.js
index c69c185362a1411aa0ebfa604699f951a194c338..62d898e6ae7a64d03a9a5a29464b12328aa1b121 100644 (file)
--- a/nt3d.js
+++ b/nt3d.js
@@ -83,6 +83,14 @@ nt3d = {
                        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.
@@ -211,7 +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