1 files changed, 150 insertions, 0 deletions
diff --git a/src/net/java/joglutils/msg/math/Line.java b/src/net/java/joglutils/msg/math/Line.java
new file mode 100644
index 0000000..2004c08
--- /dev/null
+++ b/src/net/java/joglutils/msg/math/Line.java
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2007 Sun Microsystems, 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:
+ * 
+ * - Redistribution of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ * - Redistribution in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * 
+ * Neither the name of Sun Microsystems, Inc. or the names of
+ * contributors may 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 OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
+ * MICROSYSTEMS, INC. ("SUN") AND ITS 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 SUN OR
+ * ITS 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
+ * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+ * 
+ * You acknowledge that this software is not designed or intended for use
+ * in the design, construction, operation or maintenance of any nuclear
+ * facility.
+ * 
+ */
+
+package net.java.joglutils.msg.math;
+
+/** Represents a line in 3D space. */
+
+public class Line {
+  private Vec3f point;
+  /** Normalized */
+  private Vec3f direction;
+  /** For computing projections along line */
+  private Vec3f alongVec;
+
+  /** Default constructor initializes line to point (0, 0, 0) and
+      direction (1, 0, 0) */
+  public Line() {
+    point = new Vec3f(0, 0, 0);
+    direction = new Vec3f(1, 0, 0);
+    alongVec = new Vec3f();
+    recalc();
+  }
+
+  /** Line goes in direction <b>direction</b> through the point
+      <b>point</b>. <b>direction</b> does not need to be normalized but must
+      not be the zero vector. */
+  public Line(Vec3f direction, Vec3f point) {
+    direction = new Vec3f(direction);
+    direction.normalize();
+    point = new Vec3f(point);
+    alongVec = new Vec3f();
+    recalc();
+  }
+
+  /** Setter does some work to maintain internal caches.
+      <b>direction</b> does not need to be normalized but must not be
+      the zero vector. */
+  public void setDirection(Vec3f direction) {
+    this.direction.set(direction);
+    this.direction.normalize();
+    recalc();
+  }
+
+  /** Direction is normalized internally, so <b>direction</b> is not
+      necessarily equal to <code>plane.setDirection(direction);
+      plane.getDirection();</code> */
+  public Vec3f getDirection() {
+    return direction;
+  }
+
+  /** 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 line */
+  public void projectPoint(Vec3f pt,
+                           Vec3f projPt) {
+    float dotp = direction.dot(pt);
+    projPt.set(direction);
+    projPt.scale(dotp);
+    projPt.add(alongVec);
+  }
+
+  /** Find closest point on this line to the given ray, specified by
+      start point and direction. If ray is parallel to this line,
+      returns false and closestPoint is not modified. */
+  public boolean closestPointToRay(Vec3f rayStart,
+                                   Vec3f rayDirection,
+                                   Vec3f closestPoint) {
+    // Line 1 is this one. Line 2 is the incoming one.
+    Mat2f A = new Mat2f();
+    A.set(0, 0, -direction.lengthSquared());
+    A.set(1, 1, -rayDirection.lengthSquared());
+    A.set(0, 1, direction.dot(rayDirection));
+    A.set(1, 0, A.get(0, 1));
+    if (Math.abs(A.determinant()) == 0.0f) {
+      return false;
+    }
+    if (!A.invert()) {
+      return false;
+    }
+    Vec2f b = new Vec2f();
+    b.setX(point.dot(direction) - rayStart.dot(direction));
+    b.setY(rayStart.dot(rayDirection) - point.dot(rayDirection));
+    Vec2f x = new Vec2f();
+    A.xformVec(b, x);
+    if (x.y() < 0) {
+      // Means that ray start is closest point to this line
+      closestPoint.set(rayStart);
+    } else {
+      closestPoint.set(direction);
+      closestPoint.scale(x.x());
+      closestPoint.add(point);
+    }
+    return true;
+  }
+
+  //----------------------------------------------------------------------
+  // Internals only below this point
+  //
+  
+  private void recalc() {
+    float denom = direction.lengthSquared();
+    if (denom == 0.0f) {
+      throw new RuntimeException("Line.recalc: ERROR: direction was the zero vector " +
+                                 "(not allowed)");
+    }
+    alongVec.set(point.minus(direction.times(point.dot(direction))));
+  }
+}