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/*
* 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))));
}
}
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