Incremental progress toward archive loading in o3d-webgl. Implemented...

samples/o3d-webgl/param_object.js

 /*
  * Copyright 2010, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 84 matching lines @@
  *     'WorldViewProjectionParamMatrix4'
  *     'WorldViewProjectionInverseParamMatrix4'
  *     'WorldViewProjectionTransposeParamMatrix4'
  *     'WorldViewProjectionInverseTransposeParamMatrix4'
  * @return {!o3d.Param}  The newly created Param or null on failure.
  */
 o3d.ParamObject.prototype.createParam =
     function(param_name, param_type_name) {
   if (this.params_[param_name])
     return null;
+  param_type_name = o3d.filterTypeName_(param_type_name);
   if (!o3d.global.o3d[param_type_name])
     throw ('Invalid param type name: ' + param_type_name);
   var param = new o3d.global.o3d[param_type_name];
   param.gl = this.gl;
   param.owner_ = this;
   this.params_[param_name] = param;
-  return this.params_[param_name];
+  return this.filterResult_(this.params_[param_name]);
 };
 
 
 /**
  * Searches by name for a Param defined in the object.
  * 
  * @param {string} param_name Name to search for.
  * @return {!o3d.Param}  The Param with the given name, or null otherwise.
  */
 o3d.ParamObject.prototype.getParam =
     function(param_name) {
-  return this.params_[param_name];
+  return this.filterResult_(this.params_[param_name]);
 };
 
 
 /**
  * Removes a Param from a ParamObject.
  * 
  * This function will fail if the param does not exist on this ParamObject
  * or if the param is unremovable.
  * 
  * @param {!o3d.Param} param param to remove.
@@ skipping 28 matching lines @@
  * object. Does not replace any currently existing params with the same name.
  *
  * @param {o3d.ParamObject} source_param_object param object to copy params
  *     from.
  */
 o3d.ParamObject.prototype.copyParams =
     function(source_param_object) {
   o3d.notImplemented();
 };
 
-
+/**
+ * Filters results, turning 'undefined' into 'null'.
+ * @private
+ */
+o3d.ParamObject.prototype.filterResult_= function(result) {
+  return (result ? result : null);
+};