ZoneNPoly.java

/*
 * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If
 * not, see <http://www.gnu.org/licenses/>.
 */
package silentium.gameserver.model.zone.form;

import silentium.gameserver.model.zone.L2ZoneForm;

/**
 * A not so primitive npoly zone
 * 
 * @author durgus
 */
public class ZoneNPoly extends L2ZoneForm
{
	private final int[] _x;
	private final int[] _y;
	private final int _z1;
	private final int _z2;

	public ZoneNPoly(int[] x, int[] y, int z1, int z2)
	{
		_x = x;
		_y = y;
		_z1 = z1;
		_z2 = z2;
	}

	@Override
	public boolean isInsideZone(int x, int y, int z)
	{
		if (z < _z1 || z > _z2)
			return false;

		boolean inside = false;
		for (int i = 0, j = _x.length - 1; i < _x.length; j = i++)
		{
			if ((((_y[i] <= y) && (y < _y[j])) || ((_y[j] <= y) && (y < _y[i]))) && (x < (_x[j] - _x[i]) * (y - _y[i]) / (_y[j] - _y[i]) + _x[i]))
			{
				inside = !inside;
			}
		}
		return inside;
	}

	@Override
	public boolean intersectsRectangle(int ax1, int ax2, int ay1, int ay2)
	{
		int tX, tY, uX, uY;

		// First check if a point of the polygon lies inside the rectangle
		if (_x[0] > ax1 && _x[0] < ax2 && _y[0] > ay1 && _y[0] < ay2)
			return true;

		// Or a point of the rectangle inside the polygon
		if (isInsideZone(ax1, ay1, (_z2 - 1)))
			return true;

		// If the first point wasn't inside the rectangle it might still have any line crossing any side
		// of the rectangle

		// Check every possible line of the polygon for a collision with any of the rectangles side
		for (int i = 0; i < _y.length; i++)
		{
			tX = _x[i];
			tY = _y[i];
			uX = _x[(i + 1) % _x.length];
			uY = _y[(i + 1) % _x.length];

			// Check if this line intersects any of the four sites of the rectangle
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax1, ay1, ax1, ay2))
				return true;
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax1, ay1, ax2, ay1))
				return true;
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax2, ay2, ax1, ay2))
				return true;
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax2, ay2, ax2, ay1))
				return true;
		}

		return false;
	}

	@Override
	public double getDistanceToZone(int x, int y)
	{
		double test, shortestDist = Math.pow(_x[0] - x, 2) + Math.pow(_y[0] - y, 2);

		for (int i = 1; i < _y.length; i++)
		{
			test = Math.pow(_x[i] - x, 2) + Math.pow(_y[i] - y, 2);
			if (test < shortestDist)
				shortestDist = test;
		}

		return Math.sqrt(shortestDist);
	}

	/*
	 * getLowZ() / getHighZ() - These two functions were added to cope with the demand of the new fishing algorithms, wich are now able to
	 * correctly place the hook in the water, thanks to getHighZ(). getLowZ() was added, considering potential future modifications.
	 */
	@Override
	public int getLowZ()
	{
		return _z1;
	}

	@Override
	public int getHighZ()
	{
		return _z2;
	}

	@Override
	public void visualizeZone(int z)
	{
		for (int i = 0; i < _x.length; i++)
		{
			int nextIndex = i + 1;
			// ending point to first one
			if (nextIndex == _x.length)
				nextIndex = 0;
			int vx = _x[nextIndex] - _x[i];
			int vy = _y[nextIndex] - _y[i];
			float lenght = (float) Math.sqrt(vx * vx + vy * vy);
			lenght /= STEP;
			for (int o = 1; o <= lenght; o++)
			{
				float k = o / lenght;
				dropDebugItem(57, 1, (int) (_x[i] + k * vx), (int) (_y[i] + k * vy), z);
			}
		}
	}
}