/* Copyright (C) 2011 Garrett Fleenor
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3.0 of the License, or (at
your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License (COPYING.txt) for more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation,
Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
This is a port of libnoise ( http://libnoise.sourceforge.net/index.html ). Original implementation by Jason Bevins
*/
package com.bioxx.libnoise.model;
import com.bioxx.jmapgen.Point;
import com.bioxx.libnoise.exception.NoModuleException;
import com.bioxx.libnoise.module.Module;
/**
* Model that defines the displacement of a line segment.
*
* This model returns an output value from a noise module given the
* one-dimensional coordinate of an input value located on a line segment, which
* can be used as displacements.
*
* This class is useful for creating: - roads and rivers - disaffected college
* students
*
* To generate an output value, pass an input value between 0.0 and 1.0 to the
* GetValue() method. 0.0 represents the start position of the line segment and
* 1.0 represents the end position of the line segment.
*/
public class Segment {
// A flag that specifies whether the value is to be attenuated
// (moved toward 0.0) as the ends of the line segment are approached.
boolean attenuate = false;
// A pointer to the noise module used to generate the output values.
Module module;
// @a x coordinate of the start of the line segment.
double x0 = 0;
// @a x coordinate of the end of the line segment.
double x1 = 1;
// @a y coordinate of the start of the line segment.
double y0 = 0;
// @a y coordinate of the end of the line segment.
double y1 = 1;
// @a z coordinate of the start of the line segment.
double z0 = 0;
// @a z coordinate of the end of the line segment.
double z1 = 1;
/**
* @param module The noise module that is used to generate the output
* values.
*/
public Segment(Module module) {
if (module == null)
throw new IllegalArgumentException("module cannot be null");
this.module = module;
}
/**
* Returns a flag indicating whether the output value is to be attenuated
* (moved toward 0.0) as the ends of the line segment are approached by the
* input value.
*
* @return true if the value is to be attenuated false if not.
*/
public boolean attenuate() {
return this.attenuate;
}
/**
* Sets a flag indicating that the output value is to be attenuated (moved
* toward 0.0) as the ends of the line segment are approached.
*
* @param att A flag that specifies whether the output value is to be
* attenuated.
*/
public void setAttenuate(boolean att) {
this.attenuate = att;
}
/**
* Sets the position ( @a x, @a y, @a z ) of the start of the line segment
* to choose values along.
*
* @param x x coordinate of the start position.
* @param y y coordinate of the start position.
* @param z z coordinate of the start position.
*/
public void setStartPoint(double x, double y, double z) {
this.x0 = x;
this.y0 = y;
this.z0 = z;
}
/**
* Sets the position ( @a x, @a y, @a z ) of the end of the line segment to
* choose values along.
*
* @param x x coordinate of the end position.
* @param y y coordinate of the end position.
* @param z z coordinate of the end position.
*/
public void setEndPoint(double x, double y, double z) {
this.x1 = x;
this.y1 = y;
this.z1 = z;
}
public void setPoints(Point p0, Point p1) {
this.x0 = p0.x;
this.y0 = 0;
this.z0 = p0.y;
this.x1 = p1.x;
this.y1 = 0;
this.z1 = p1.y;
}
/**
* Returns the noise module that is used to generate the output values.
*
* @returns A reference to the noise module.
* @pre A noise module was passed to the SetModule() method.
*/
public Module getModule() {
return module;
}
/**
* Sets the noise module that is used to generate the output values.
*
* @param module The noise module that is used to generate the output
* values.
*
* This noise module must exist for the lifetime of this object,
* until you pass a new noise module to this method.
*/
public void setModule(Module module) {
if (module == null)
throw new IllegalArgumentException("module cannot be null");
this.module = module;
}
/**
* Returns the output value from the noise module given the one-dimensional
* coordinate of the specified input value located on the line segment.
*
* @param p The distance along the line segment (ranges from 0.0 to 1.0)
* @return The output value from the noise module.
* @pre A noise module was passed to the SetModule() method.
* @pre The start and end points of the line segment were specified.
*
* The output value is generated by the noise module passed to the
* SetModule() method. This value may be attenuated (moved toward 0.0)
* as @a p approaches either end of the line segment; this is the
* default behavior.
*
* If the value is not to be attenuated, @a p can safely range outside
* the 0.0 to 1.0 range; the output value will be extrapolated along
* the line that this segment is part of.
*/
public double getValue(double p) {
if (module == null)
throw new NoModuleException();
double x = (x1 - x0) * p + x0;
double y = (y1 - y0) * p + y0;
double z = (z1 - z0) * p + z0;
double value = module.GetValue(x, y, z);
if (attenuate) {
return p * (1.0 - p) * 4 * value;
} else {
return value;
}
}
}