/* Copyright (c) 2013 Jesper Öqvist <jesper@llbit.se>
 *
 * This file is part of Chunky.
 *
 * Chunky 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.
 *
 * Chunky 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 Chunky.  If not, see <http://www.gnu.org/licenses/>.
 */
package se.llbit.chunky.model;

import se.llbit.chunky.resources.Texture;
import se.llbit.chunky.world.BlockData;
import se.llbit.math.AABB;
import se.llbit.math.Ray;

/**
 * Anvil block.
 *
 * @author Jesper Öqvist <jesper@llbit.se>
 */
public class AnvilModel {
  private static final AABB[][] boxes = {
      // north-south
      {new AABB(3 / 16., 13 / 16., 10 / 16., 1, 0, 1),
          new AABB(2 / 16., 14 / 16., 0, 4 / 16., 2 / 16., 14 / 16.),
          new AABB(4 / 16., 12 / 16., 4 / 16., 5 / 16., 3 / 16., 13 / 16.),
          new AABB(6 / 16., 10 / 16., 5 / 16., 10 / 16., 4 / 16., 12 / 16.),},
      // east-west
      {new AABB(0, 1, 10 / 16., 1, 3 / 16., 13 / 16.),
          new AABB(2 / 16., 14 / 16., 0, 4 / 16., 2 / 16., 14 / 16.),
          new AABB(3 / 16., 13 / 16., 4 / 16., 5 / 16., 4 / 16., 12 / 16.),
          new AABB(4 / 16., 12 / 16., 5 / 16., 10 / 16., 6 / 16., 10 / 16.),},};

  public static final Texture[] topTexture =
      {Texture.anvilTop, Texture.anvilTopDamaged1, Texture.anvilTopDamaged2,
          Texture.anvilTopDamaged2};

  /**
   * Find intersection between ray and block
   *
   * @return <code>true</code> if the ray intersected the block
   */
  public static boolean intersect(Ray ray) {
    int data = ray.getCurrentData() >> BlockData.OFFSET;
    int orientation = 1 & data;
    int damage = 3 & (data >> 2);
    boolean hit = false;
    ray.t = Double.POSITIVE_INFINITY;
    for (int i = 0; i < boxes[0].length; ++i) {
      if (boxes[orientation][i].intersect(ray)) {
        if (i == 0 && ray.n.y > 0) {
          double tmp = ray.v;
          ray.v = ray.u * orientation + tmp * (1 - orientation);
          ray.u = tmp * orientation + ray.u * (1 - orientation);
          topTexture[damage].getColor(ray);
        } else {
          Texture.anvilSide.getColor(ray);
        }
        ray.t = ray.tNext;
        hit = true;
      }
    }
    if (hit) {
      ray.color.w = 1;
      ray.distance += ray.t;
      ray.o.scaleAdd(ray.t, ray.d);
    }
    return hit;
  }
}