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/*
* gleem -- OpenGL Extremely Easy-To-Use Manipulators.
* Copyright (C) 1998-2003 Kenneth B. Russell (kbrussel@alum.mit.edu)
*
* 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 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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