/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
package com.badlogic.gdx.math;
import java.io.Serializable;
/** A plane defined via a unit length normal and the distance from the origin, as you learned in your math class.
*
* @author badlogicgames@gmail.com */
public class Plane implements Serializable {
private static final long serialVersionUID = -1240652082930747866L;
/** Enum specifying on which side a point lies respective to the plane and it's normal. {@link PlaneSide#Front} is the side to
* which the normal points.
*
* @author mzechner */
public enum PlaneSide {
OnPlane, Back, Front
}
public final Vector3 normal = new Vector3();
public float d = 0;
/**
* Constructs a new plane with all values set to 0
*/
public Plane () {
}
/** Constructs a new plane based on the normal and distance to the origin.
*
* @param normal The plane normal
* @param d The distance to the origin */
public Plane (Vector3 normal, float d) {
this.normal.set(normal).nor();
this.d = d;
}
/** Constructs a new plane based on the normal and a point on the plane.
*
* @param normal The normal
* @param point The point on the plane */
public Plane (Vector3 normal, Vector3 point) {
this.normal.set(normal).nor();
this.d = -this.normal.dot(point);
}
/** Constructs a new plane out of the three given points that are considered to be on the plane. The normal is calculated via a
* cross product between (point1-point2)x(point2-point3)
*
* @param point1 The first point
* @param point2 The second point
* @param point3 The third point */
public Plane (Vector3 point1, Vector3 point2, Vector3 point3) {
set(point1, point2, point3);
}
/** Sets the plane normal and distance to the origin based on the three given points which are considered to be on the plane.
* The normal is calculated via a cross product between (point1-point2)x(point2-point3)
*
* @param point1
* @param point2
* @param point3 */
public void set (Vector3 point1, Vector3 point2, Vector3 point3) {
normal.set(point1).sub(point2).crs(point2.x-point3.x, point2.y-point3.y, point2.z-point3.z).nor();
d = -point1.dot(normal);
}
/** Sets the plane normal and distance
*
* @param nx normal x-component
* @param ny normal y-component
* @param nz normal z-component
* @param d distance to origin */
public void set (float nx, float ny, float nz, float d) {
normal.set(nx, ny, nz);
this.d = d;
}
/** Calculates the shortest signed distance between the plane and the given point.
*
* @param point The point
* @return the shortest signed distance between the plane and the point */
public float distance (Vector3 point) {
return normal.dot(point) + d;
}
/** Returns on which side the given point lies relative to the plane and its normal. PlaneSide.Front refers to the side the
* plane normal points to.
*
* @param point The point
* @return The side the point lies relative to the plane */
public PlaneSide testPoint (Vector3 point) {
float dist = normal.dot(point) + d;
if (dist == 0)
return PlaneSide.OnPlane;
else if (dist < 0)
return PlaneSide.Back;
else
return PlaneSide.Front;
}
/** Returns on which side the given point lies relative to the plane and its normal. PlaneSide.Front refers to the side the
* plane normal points to.
*
* @param x
* @param y
* @param z
* @return The side the point lies relative to the plane */
public PlaneSide testPoint (float x, float y, float z) {
float dist = normal.dot(x, y, z) + d;
if (dist == 0)
return PlaneSide.OnPlane;
else if (dist < 0)
return PlaneSide.Back;
else
return PlaneSide.Front;
}
/** Returns whether the plane is facing the direction vector. Think of the direction vector as the direction a camera looks in.
* This method will return true if the front side of the plane determined by its normal faces the camera.
*
* @param direction the direction
* @return whether the plane is front facing */
public boolean isFrontFacing (Vector3 direction) {
float dot = normal.dot(direction);
return dot <= 0;
}
/** @return The normal */
public Vector3 getNormal () {
return normal;
}
/** @return The distance to the origin */
public float getD () {
return d;
}
/** Sets the plane to the given point and normal.
*
* @param point the point on the plane
* @param normal the normal of the plane */
public void set (Vector3 point, Vector3 normal) {
this.normal.set(normal);
d = -point.dot(normal);
}
public void set (float pointX, float pointY, float pointZ, float norX, float norY, float norZ) {
this.normal.set(norX, norY, norZ);
d = -(pointX * norX + pointY * norY + pointZ * norZ);
}
/** Sets this plane from the given plane
*
* @param plane the plane */
public void set (Plane plane) {
this.normal.set(plane.normal);
this.d = plane.d;
}
public String toString () {
return normal.toString() + ", " + d;
}
}