/* Copyright (c) 2012 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.math.Quad;
import se.llbit.math.Ray;
import se.llbit.math.Vector3;
import se.llbit.math.Vector4;

public class ButtonModel {
  protected static Quad[] attachedSouth = {
      // front
      new Quad(new Vector3(.6875, .375, .875), new Vector3(.3125, .375, .875),
          new Vector3(.6875, .625, .875), new Vector4(.6875, .3125, .375, .625)),

      // back
      new Quad(new Vector3(.3125, .375, 1), new Vector3(.6875, .375, 1),
          new Vector3(.3125, .625, 1), new Vector4(.3125, .6875, .375, .625)),

      // right
      new Quad(new Vector3(.3125, .375, .875), new Vector3(.3125, .375, 1),
          new Vector3(.3125, .625, .875), new Vector4(.875, 1, .375, .625)),

      // left
      new Quad(new Vector3(.6875, .375, 1), new Vector3(.6875, .375, .875),
          new Vector3(.6875, .625, 1), new Vector4(1, .875, .375, .625)),

      // top
      new Quad(new Vector3(.6875, .625, .875), new Vector3(.3125, .625, .875),
          new Vector3(.6875, .625, 1), new Vector4(.6875, .3125, .875, 1)),

      // bottom
      new Quad(new Vector3(.3125, .375, .875), new Vector3(.6875, .375, .875),
          new Vector3(.3125, .375, 1), new Vector4(.3125, .6875, .875, 1)),

  };

  private static Quad[][] variant = new Quad[8][];

  static {
    // data bits: (part of block attached to)
    // 000 => top
    // 001 => west
    // 010 => east
    // 011 => north
    // 100 => south
    // 101 => up
    // 110 => undefined
    // 111 => undefined
    // last updated for MC 1.8
    variant[4] = attachedSouth;
    variant[1] = Model.rotateY(attachedSouth);
    variant[3] = Model.rotateY(variant[1]);
    variant[2] = Model.rotateY(variant[3]);
    variant[0] = Model.rotateNegX(attachedSouth);
    variant[5] = Model.rotateX(attachedSouth);
    variant[6] = attachedSouth;
    variant[7] = attachedSouth;
  }

  public static boolean intersect(Ray ray, Texture texture) {
    boolean hit = false;
    Quad[] rotated = variant[ray.getBlockData() & 7];
    ray.t = Double.POSITIVE_INFINITY;
    for (Quad quad : rotated) {
      if (quad.intersect(ray)) {
        texture.getColor(ray);
        ray.n.set(quad.n);
        ray.t = ray.tNext;
        hit = true;
      }
    }
    if (hit) {
      ray.color.w = 1;// always opaque
      ray.distance += ray.t;
      ray.o.scaleAdd(ray.t, ray.d);
    }
    return hit;
  }
}