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diff --git a/src/gleem/linalg/Plane.java b/src/gleem/linalg/Plane.java
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+/*
+ * gleem -- OpenGL Extremely Easy-To-Use Manipulators.
+ * Copyright (C) 1998-2003 Kenneth B. Russell ([email protected])
+ *
+ * Copying, distribution and use of this software in source and binary
+ * forms, with or without modification, is permitted provided that the
+ * following conditions are met:
+ *
+ * Distributions of source code must reproduce the copyright notice,
+ * this list of conditions and the following disclaimer in the source
+ * code header files; and Distributions of binary code must reproduce
+ * the copyright notice, this list of conditions and the following
+ * disclaimer in the documentation, Read me file, license file and/or
+ * other materials provided with the software distribution.
+ *
+ * The names of Sun Microsystems, Inc. ("Sun") and/or the copyright
+ * holder may not be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS," WITHOUT A WARRANTY OF ANY
+ * KIND. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
+ * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, NON-INTERFERENCE, ACCURACY OF
+ * INFORMATIONAL CONTENT OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. THE
+ * COPYRIGHT HOLDER, SUN AND SUN'S LICENSORS SHALL NOT BE LIABLE FOR
+ * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
+ * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL THE
+ * COPYRIGHT HOLDER, SUN OR SUN'S LICENSORS BE LIABLE FOR ANY LOST
+ * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
+ * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
+ * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
+ * INABILITY TO USE THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGES. YOU ACKNOWLEDGE THAT THIS SOFTWARE IS NOT
+ * DESIGNED, LICENSED OR INTENDED FOR USE IN THE DESIGN, CONSTRUCTION,
+ * OPERATION OR MAINTENANCE OF ANY NUCLEAR FACILITY. THE COPYRIGHT
+ * HOLDER, SUN AND SUN'S LICENSORS DISCLAIM ANY EXPRESS OR IMPLIED
+ * WARRANTY OF FITNESS FOR SUCH USES.
+ */
+
+package gleem.linalg;
+
+/** Represents a plane in 3D space. */
+
+public class Plane {
+  /** Normalized */
+  private Vec3f normal;
+  private Vec3f point;
+  /** Constant for faster projection and intersection */
+  float c;
+
+  /** Default constructor initializes normal to (0, 1, 0) and point to
+      (0, 0, 0) */
+  public Plane() {
+    normal = new Vec3f(0, 1, 0);
+    point = new Vec3f(0, 0, 0);
+    recalc();
+  }
+
+  /** Sets all parameters of plane. Plane has normal <b>normal</b> and
+      goes through the point <b>point</b>. Normal does not need to be
+      unit length but must not be the zero vector. */
+  public Plane(Vec3f normal, Vec3f point) {
+    this.normal = new Vec3f(normal);
+    this.normal.normalize();
+    this.point = new Vec3f(point);
+    recalc();
+  }
+
+  /** Setter does some work to maintain internal caches. Normal does
+      not need to be unit length but must not be the zero vector. */
+  public void setNormal(Vec3f normal) {
+    this.normal.set(normal);
+    this.normal.normalize();
+    recalc();
+  }
+
+  /** Normal is normalized internally, so <b>normal</b> is not
+      necessarily equal to <code>plane.setNormal(normal);
+      plane.getNormal();</code> */
+  public Vec3f getNormal() {
+    return normal;
+  }
+
+  /** Setter does some work to maintain internal caches */
+  public void setPoint(Vec3f point) {
+    this.point.set(point);
+    recalc();
+  }
+
+  public Vec3f getPoint() {
+    return point;
+  }
+
+  /** Project a point onto the plane */
+  public void projectPoint(Vec3f pt,
+                           Vec3f projPt) {
+    float scale = normal.dot(pt) - c;
+    projPt.set(pt.minus(normal.times(normal.dot(point) - c)));
+  }
+
+  /** Intersect a ray with the plane. Returns true if intersection occurred, false
+      otherwise. This is a two-sided ray cast. */
+  public boolean intersectRay(Vec3f rayStart,
+                              Vec3f rayDirection,
+                              IntersectionPoint intPt) {
+    float denom = normal.dot(rayDirection);
+    if (denom == 0)
+      return false;
+    intPt.setT((c - normal.dot(rayStart)) / denom);
+    intPt.setIntersectionPoint(rayStart.plus(rayDirection.times(intPt.getT())));
+    return true;
+  }
+
+  //----------------------------------------------------------------------
+  // Internals only below this point
+  //
+  
+  private void recalc() {
+    c = normal.dot(point);
+  }
+}