/*
* WorldEdit, a Minecraft world manipulation toolkit
* Copyright (C) sk89q <http://www.sk89q.com>
* Copyright (C) WorldEdit team and contributors
*
* This program 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 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.sk89q.worldedit.math.geom;
import com.sk89q.worldedit.BlockVector2D;
import com.sk89q.worldedit.Vector2D;
import java.util.ArrayList;
import java.util.List;
/**
* Helper method for anything related to polygons.
*/
public final class Polygons {
private Polygons() {
}
/**
* Calculates the polygon shape of a cylinder which can then be used for e.g. intersection detection.
*
* @param center the center point of the cylinder
* @param radius the radius of the cylinder
* @param maxPoints max points to be used for the calculation
* @return a list of {@link BlockVector2D} which resemble the shape as a polygon
*/
public static List<BlockVector2D> polygonizeCylinder(Vector2D center, Vector2D radius, int maxPoints) {
int nPoints = (int) Math.ceil(Math.PI*radius.length());
// These strange semantics for maxPoints are copied from the selectSecondary method.
if (maxPoints >= 0 && nPoints >= maxPoints) {
nPoints = maxPoints - 1;
}
final List<BlockVector2D> points = new ArrayList<BlockVector2D>(nPoints);
for (int i = 0; i < nPoints; ++i) {
double angle = i * (2.0 * Math.PI) / nPoints;
final Vector2D pos = new Vector2D(Math.cos(angle), Math.sin(angle));
final BlockVector2D blockVector2D = pos.multiply(radius).add(center).toBlockVector2D();
points.add(blockVector2D);
}
return points;
}
}