org.recast4j.detour.crowd.ProximityGrid Maven / Gradle / Ivy

Go to download
/*
Copyright (c) 2009-2010 Mikko Mononen [email protected]
recast4j copyright (c) 2015-2019 Piotr Piastucki [email protected]

This software is provided 'as-is', without any express or implied
warranty.  In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
 claim that you wrote the original software. If you use this software
 in a product, an acknowledgment in the product documentation would be
 appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
 misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
package org.recast4j.detour.crowd;

import static java.util.stream.Collectors.toList;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class ProximityGrid {

    private final float m_cellSize;
    private final float m_invCellSize;
    private final Map> items;

    public ProximityGrid(float m_cellSize) {
        this.m_cellSize = m_cellSize;
        m_invCellSize = 1.0f / m_cellSize;
        items = new HashMap<>();
    }

    void clear() {
        items.clear();
    }

    void addItem(CrowdAgent agent, float minx, float miny, float maxx, float maxy) {
        int iminx = (int) Math.floor(minx * m_invCellSize);
        int iminy = (int) Math.floor(miny * m_invCellSize);
        int imaxx = (int) Math.floor(maxx * m_invCellSize);
        int imaxy = (int) Math.floor(maxy * m_invCellSize);

        for (int y = iminy; y <= imaxy; ++y) {
            for (int x = iminx; x <= imaxx; ++x) {
                ItemKey key = new ItemKey(x, y);
                List ids = items.get(key);
                if (ids == null) {
                    ids = new ArrayList<>();
                    items.put(key, ids);
                }
                ids.add(agent);
            }
        }
    }

    Set queryItems(float minx, float miny, float maxx, float maxy) {
        int iminx = (int) Math.floor(minx * m_invCellSize);
        int iminy = (int) Math.floor(miny * m_invCellSize);
        int imaxx = (int) Math.floor(maxx * m_invCellSize);
        int imaxy = (int) Math.floor(maxy * m_invCellSize);

        Set result = new HashSet<>();
        for (int y = iminy; y <= imaxy; ++y) {
            for (int x = iminx; x <= imaxx; ++x) {
                ItemKey key = new ItemKey(x, y);
                List ids = items.get(key);
                if (ids != null) {
                    result.addAll(ids);
                }
            }
        }

        return result;
    }

    public List getItemCounts() {
        return items.entrySet().stream().filter(e -> e.getValue() != null && e.getValue().size() > 0)
                .map(e -> new int[] { e.getKey().x, e.getKey().y, e.getValue().size() }).collect(toList());
    }

    public float getCellSize() {
        return m_cellSize;
    }

    private static class ItemKey {

        int x, y;

        public ItemKey(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override
        public int hashCode() {
            final int prime = 31;
            int result = 1;
            result = prime * result + x;
            result = prime * result + y;
            return result;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj)
                return true;
            if (obj == null)
                return false;
            if (getClass() != obj.getClass())
                return false;
            ItemKey other = (ItemKey) obj;
            if (x != other.x)
                return false;
            if (y != other.y)
                return false;
            return true;
        }

    };
}