world.java

j3me java

/*
 * J3DME Fast 3D software rendering for small devices
 * Copyright (C) 2001 Onno Hommes
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package net.jscience.j3dme;

/**
 * Objects of this class represent a virtual world. The virtual world
 * can hold one or more models. Models are 3D objects that have a defined
 * geometry and a location in this virtual world.
 * @see Model
 */
public class World
{
  public static final int ONE = 256;

  private Model[] models;
  private int empty = 0;
  private int next  = 0;

  /**
   * Return a virtual world.<p>
   * Return a virtual world that can hold the number of specified models
   * The number of models cannot be changed during the life of the world.
   *
   * @param     numberOfModels The maximum number of models this world can host
   * @return The virtual world.
   */
  public World(int numberOfModels){
     models = new Model[numberOfModels];
  }

  /**
   * Add a model to the virtual world<p>
   * The supplied model will be added to the virtual world and a model
   * index will be returned. If you receive a model index of -1 then the
   * world cannot host the model because it has reached its maximum capacity.
   *
   * @param     model The model to add to the world
   * @return The world index to the model or -1 if full.
   */
  public int addModel(Model model){
    if (empty==models.length) return -1;
    models[empty] = model;
    empty++;
    return empty-1;
  }

  /**
   * Remove the model from the world<p>
   *
   * @param     model The model to remove.
   */
  public void removeModel(Model model){
      removeModel(getModelIndex(model));
  }

  /**
   * Remove a model by index<p>
   * The supplied index will be used to remove a model from the world.
   *
   * @param     index The index to the model
   */
  public void removeModel(int index){
      if (index >= 0 && index < empty){
         while (index < empty){
            models[index]=models[index+1];
            index++;
         }
      empty--;
      }
  }

  /**
   * Return the model located at the index<p>
   * This method does not check for incorrect indices. Indices
   * larger then the worlds capacity minus one or negative indices will
   * surely give you some expected array Execptions.
   *
   * @param     index The index to the model to be retrieved
   * @return The model at the supplied index
   */
  public Model getModel(int index){
    return models[index];
  }


  /**
   * Return the current number of models in the world<p>
   *
   * @return the number of models in the world.
   */
  public int getNumberOfModels(){
    return empty;
  }

  /**
   * Return the model index for the specified model<p>
   * Return the index in the world to the supplied model.
   */
  public int getModelIndex(Model model){
     int index = -1;
     for (int i=0;i<models.length;i++){
       if (models[i] == model) {
          index = i;
          break;
       }
     }
     return index;
  }
  public int getMaximumModels(){
    return(models.length);
  }
}