The thing the Rostock was printing in Make Magazine

[nt3d] / nt3d.js

diff --git a/nt3d.js b/nt3d.js
index 9b09b09532e233aa5b450130bd36d4bd43be02e2..62d898e6ae7a64d03a9a5a29464b12328aa1b121 100644 (file)
--- 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