Import libtess.js

src/libtess.js/sweep/ActiveRegion.js

@@ -0,0 +1,116 @@
+/**
+ * Copyright 2000, Silicon Graphics, Inc. All Rights Reserved.
+ * Copyright 2012, Google Inc. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice including the dates of first publication and
+ * either this permission notice or a reference to http://oss.sgi.com/projects/FreeB/
+ * shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+ * IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Original Code. The Original Code is: OpenGL Sample Implementation,
+ * Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+ * Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+ * Copyright in any portions created by third parties is as indicated
+ * elsewhere herein. All Rights Reserved.
+ */
+
+/**
+ * @author Eric Veach, July 1994
+ * @author Brendan Kenny
+ */
+
+
+// require libtess
+// require libtess.DictNode
+// require libtess.GluHalfEdge
+/*global libtess */
+
+// TODO(bckenny): apparently only visible outside of sweep for debugging routines.
+// find out if we can hide
+
+/**
+ * For each pair of adjacent edges crossing the sweep line, there is
+ * an ActiveRegion to represent the region between them. The active
+ * regions are kept in sorted order in a dynamic dictionary.  As the
+ * sweep line crosses each vertex, we update the affected regions.
+ *
+ * @constructor
+ */
+libtess.ActiveRegion = function() {
+  // TODO(bckenny): I *think* eUp and nodeUp could be passed in as constructor params
+
+  /**
+   * upper edge, directed right to left
+   * @type {libtess.GluHalfEdge}
+   */
+  this.eUp = null;
+
+  /**
+   * dictionary node corresponding to eUp
+   * @type {libtess.DictNode}
+   */
+  this.nodeUp = null;
+
+  /**
+   * used to determine which regions are inside the polygon
+   * @type {number}
+   */
+  this.windingNumber = 0;
+
+  /**
+   * is this region inside the polygon?
+   * @type {boolean}
+   */
+  this.inside = false;
+  
+  /**
+   * marks fake edges at t = +/-infinity
+   * @type {boolean}
+   */
+  this.sentinel = false;
+  
+  /**
+   * Marks regions where the upper or lower edge has changed, but we haven't
+   * checked whether they intersect yet.
+   * @type {boolean}
+   */
+  this.dirty = false;
+
+  /**
+   * marks temporary edges introduced when we process a "right vertex" (one
+   * without any edges leaving to the right)
+   * @type {boolean}
+   */
+  this.fixUpperEdge = false;
+};
+
+/**
+ * [regionBelow description]
+ * @return {libtess.ActiveRegion} [description]
+ */
+libtess.ActiveRegion.prototype.regionBelow = function() {
+  // TODO(bckenny): better typing? or is cast unavoidable
+  return /** @type {libtess.ActiveRegion} */ (this.nodeUp.getPred().getKey());
+};
+
+/**
+ * [regionAbove description]
+ * @return {libtess.ActiveRegion} [description]
+ */
+libtess.ActiveRegion.prototype.regionAbove = function() {
+  // TODO(bckenny): better typing? or is cast unavoidable
+  return /** @type {libtess.ActiveRegion} */ (this.nodeUp.getSucc().getKey());
+};