modify docs and a demo; fix issues with glutil-eval.js

Author: peteroupc

demos/surfaces.html

@@ -14,6 +14,7 @@
 <a href="javascript:link1()">Superellipsoid</a>,
 <a href="javascript:link2()">Klein bottle</a>,
 <a href="javascript:link3()">M&ouml;bius strip</a>,
+<a href="javascript:link3a()">M&ouml;bius-like strip</a>,
 <a href="javascript:link4()">Surface of revolution for f(x) = sin x</a>,
 <a href="javascript:link5()">Surface of revolution for f(x) = x<sup>2</sup></a>,
 <a href="javascript:link6()">Supertoroid</a>
@@ -123,7 +124,25 @@
  }
 }
 
-var MoebiusStrip=function(maj, a, b){
+var MoebiusStrip=function(radius,width){
+ this.radius=radius==null ? 1 : radius;
+ this.width=width==null ? 0.5 : width;
+ this.evaluate=function(u,v){
+  u=-this.width+(this.width*2)*u;
+  v*=GLMath.PiTimes2;
+  var x, y, z;
+  var sinv=Math.sin(v);
+  var cosv=Math.cos(v);
+  var sinv2=Math.sin(v/2);
+  var tmp=u*Math.cos(v/2)+this.radius;
+  x=cosv*tmp;
+  y=sinv*tmp;
+  z=sinv2*u;
+  return [x,y,z]
+ }
+}
+
+var MoebiusLikeStrip=function(maj, a, b){
  this.maj=maj==null ? 1.25 : maj
  this.a=a==null ? 0.125 : a
  this.b=b==null ? 0.5 : b
@@ -192,6 +211,11 @@
  scene.addShape(shape=scene.makeShape(makeMesh(new MoebiusStrip())).setMaterial(material));
 }
 
+
+function link3a(){
+ scene.removeShape(shape);
+ scene.addShape(shape=scene.makeShape(makeMesh(new MoebiusLikeStrip())).setMaterial(material));
+}
 function link4(){
  scene.removeShape(shape);
  scene.addShape(shape=scene.makeShape(makeMesh(new RevolutionSurface(function(x){

glutil-eval.js

@@ -8,6 +8,11 @@ at: http://upokecenter.dreamhosters.com/articles/donate-now-2/
 */
 (function(global){
 /** @private */
+function BernsteinEval(order){
+ this.order=order;
+ this.n=this.order-1;
+}
+/** @private */
 BernsteinEval._binomial=[ [1],
   [1,1],
   [1,2,1],
@@ -42,11 +47,6 @@ BernsteinEval._factorial=function(n) {
   return result;
 }
 /** @private */
-function BernsteinEval(order){
- this.order=order;
- this.n=this.order-1;
-}
-/** @private */
 BernsteinEval.prototype.getFactor=function(t, i){
  var bino;
  if(i==0){
@@ -253,7 +253,7 @@ function BezierSurface(cp, u1, u2, v1, v2){
 * @class
 * @alias CurveEval
 */
-function CurveEval(){
+var CurveEval=function(){
  this.colorCurve=null;
  this.normalCurve=null;
  this.texCoordCurve=null;
@@ -455,7 +455,7 @@ CurveEval.prototype.evalCurve=function(mesh,mode,n,u1,u2){
 * @class
 * @alias glutil.SurfaceEval
 */
-this.SurfaceEval=function(){
+var SurfaceEval=function(){
  this.colorSurface=null;
  this.normalSurface=null;
  this.texCoordSurface=null;
@@ -743,4 +743,6 @@ SurfaceEval.prototype.evalSurface=function(mesh,mode,un,vn,u1,u2,v1,v2){
  }
  return this;
 }
+global.SurfaceEval=SurfaceEval;
+global.CurveEval=CurveEval;
 })(this);