BlockRaytracer.java

/*
 * Copyright 2012 Benjamin Glatzel <benjamin.glatzel@me.com>
 *
 * 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 org.terasology.logic;

import org.terasology.logic.world.WorldProvider;
import org.terasology.model.structures.RayBlockIntersection;
import org.terasology.teraspout.TeraBlock;

import javax.vecmath.Vector3d;
import javax.vecmath.Vector3f;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * @author Immortius
 */
public class BlockRaytracer {

    public static RayBlockIntersection.Intersection trace(Vector3d from, Vector3d direction, WorldProvider worldProvider) {
        List<RayBlockIntersection.Intersection> inters = new ArrayList<RayBlockIntersection.Intersection>();

        Vector3f pos = new Vector3f(from);

        int blockPosX, blockPosY, blockPosZ;

        for (int x = -3; x <= 3; x++) {
            for (int y = -3; y <= 3; y++) {
                for (int z = -3; z <= 3; z++) {
                    // Make sure the correct block positions are calculated relatively to the position of the player
                    blockPosX = (int) (pos.x + (pos.x >= 0 ? 0.5f : -0.5f)) + x;
                    blockPosY = (int) (pos.y + (pos.y >= 0 ? 0.5f : -0.5f)) + y;
                    blockPosZ = (int) (pos.z + (pos.z >= 0 ? 0.5f : -0.5f)) + z;

                    TeraBlock blockType = worldProvider.getBlock(blockPosX, blockPosY, blockPosZ);

                    // Ignore special blocks
                    if (blockType.isSelectionRayThrough()) {
                        continue;
                    }

                    // The ray originates from the "player's eye"
                    List<RayBlockIntersection.Intersection> iss = RayBlockIntersection.executeIntersection(worldProvider, blockPosX, blockPosY, blockPosZ, from, direction);

                    if (iss != null) {
                        inters.addAll(iss);
                    }
                }
            }
        }

        /**
         * Calculated the closest intersection.
         */
        if (inters.size() > 0) {
            Collections.sort(inters);
            return inters.get(0);
        }

        return null;
    }
}