Allows specification of epsilon while retaining original defaults and API for compatibility (unless a dependency relies on the function.length)

Author: monfera

README.md

@@ -14,11 +14,11 @@ Here is how to compute the vertex and face normals for the Stanford bunny:
 
 ```js
     var bunny = require("bunny");
-    bunny.vertexNormals = require("normals").vertexNormals(bunny.cells, bunny.positions);
-    bunny.faceNormals = require("normals").faceNormals(bunny.cells, bunny.positions);
+    bunny.vertexNormals = require("normals").vertexNormals(bunny.cells, bunny.positions[,epsilon]);
+    bunny.faceNormals = require("normals").faceNormals(bunny.cells, bunny.positions[,epsilon]);
 ```
 
-`require("normals").vertexNormals(cells, positions)`
+`require("normals").vertexNormals(cells, positions[,epsilon])`
 ----------------------------------------------------
 This estimates the vertex normals for an oriented mesh.
 
@@ -28,7 +28,7 @@ This estimates the vertex normals for an oriented mesh.
 Returns: An array of length = `positions.length` of the per-vertex normals.
 
 
-`require("normals").faceNormals(cells, positions)`
+`require("normals").faceNormals(cells, positions[,epsilon])`
 ----------------------------------------------------
 This estimates the face normals for an oriented mesh.
 

normals.js

@@ -1,33 +1,35 @@
-var EPSILON = 1e-6;
+var DEFAULT_NORMALS_EPSILON = 1e-6;
+var DEFAULT_FACE_EPSILON = 1e-6;
 
 //Estimate the vertex normals of a mesh
-exports.vertexNormals = function(faces, positions) {
-  
+exports.vertexNormals = function(faces, positions, specifiedEpsilon) {
+
   var N         = positions.length;
   var normals   = new Array(N);
-  
+  var epsilon   = specifiedEpsilon === void(0) ? DEFAULT_NORMALS_EPSILON : specifiedEpsilon;
+
   //Initialize normal array
   for(var i=0; i<N; ++i) {
     normals[i] = [0.0, 0.0, 0.0];
   }
-  
+
   //Walk over all the faces and add per-vertex contribution to normal weights
   for(var i=0; i<faces.length; ++i) {
     var f = faces[i];
     var p = 0;
     var c = f[f.length-1];
     var n = f[0];
     for(var j=0; j<f.length; ++j) {
-    
+
       //Shift indices back
       p = c;
       c = n;
       n = f[(j+1) % f.length];
-    
+
       var v0 = positions[p];
       var v1 = positions[c];
       var v2 = positions[n];
-      
+
       //Compute infineteismal arcs
       var d01 = new Array(3);
       var m01 = 0.0;
@@ -41,7 +43,7 @@ exports.vertexNormals = function(faces, positions) {
       }
 
       //Accumulate values in normal
-      if(m01 * m21 > EPSILON) {
+      if(m01 * m21 > epsilon) {
         var norm = normals[c];
         var w = 1.0 / Math.sqrt(m01 * m21);
         for(var k=0; k<3; ++k) {
@@ -52,15 +54,15 @@ exports.vertexNormals = function(faces, positions) {
       }
     }
   }
-  
+
   //Scale all normals to unit length
   for(var i=0; i<N; ++i) {
     var norm = normals[i];
     var m = 0.0;
     for(var k=0; k<3; ++k) {
       m += norm[k] * norm[k];
     }
-    if(m > EPSILON) {
+    if(m > epsilon) {
       var w = 1.0 / Math.sqrt(m);
       for(var k=0; k<3; ++k) {
         norm[k] *= w;
@@ -77,24 +79,26 @@ exports.vertexNormals = function(faces, positions) {
 }
 
 //Compute face normals of a mesh
-exports.faceNormals = function(faces, positions) {
+exports.faceNormals = function(faces, positions, specifiedEpsilon) {
+
   var N         = faces.length;
   var normals   = new Array(N);
-  
+  var epsilon   = specifiedEpsilon === void(0) ? DEFAULT_FACE_EPSILON : specifiedEpsilon;
+
   for(var i=0; i<N; ++i) {
     var f = faces[i];
     var pos = new Array(3);
     for(var j=0; j<3; ++j) {
       pos[j] = positions[f[j]];
     }
-    
+
     var d01 = new Array(3);
     var d21 = new Array(3);
     for(var j=0; j<3; ++j) {
       d01[j] = pos[1][j] - pos[0][j];
       d21[j] = pos[2][j] - pos[0][j];
     }
-    
+
     var n = new Array(3);
     var l = 0.0;
     for(var j=0; j<3; ++j) {
@@ -103,7 +107,7 @@ exports.faceNormals = function(faces, positions) {
       n[j] = d01[u] * d21[v] - d01[v] * d21[u];
       l += n[j] * n[j];
     }
-    if(l > EPSILON) {
+    if(l > epsilon) {
       l = 1.0 / Math.sqrt(l);
     } else {
       l = 0.0;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "normals",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "description": "Estimates normals for meshes",
   "main": "normals.js",
   "repository": {