BufferObject.java :  » Game » rokon » com » stickycoding » rokon » Android Open Source

package com.stickycoding.rokon;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;

import android.os.Build;

/**
 * BufferObject.java
 * Some functions for Buffers
 * 
 * @author Richard 
 */

public class BufferObject {

  protected ByteBuffer byteBuffer;
  protected int size;
  
  /**
   * Returns the size of the buffer, ie number of points
   * 
   * @return integer buffer size
   */
  public int getSize() {
    return size;
  }
  
  /**
   * Creates a BufferObject, with a specific length and empty values 
   * 
   * @param length a valid integer, number of points
   */
  public BufferObject(int length) {
    if(Build.VERSION.SDK == "3")
      byteBuffer = ByteBuffer.allocate(length*4);
    else
      byteBuffer = ByteBuffer.allocateDirect(length*4);
    byteBuffer.order(ByteOrder.nativeOrder());  
    size = length;
  }
  
  /**
   * Creates a BufferObject from a given float array
   * 
   * @param floats an array of points for the buffer
   */
  public BufferObject(float[] floats) {
    if(Build.VERSION.SDK == "3")
      byteBuffer = ByteBuffer.allocate(floats.length * 4);
    else
      byteBuffer = ByteBuffer.allocateDirect(floats.length * 4);
    byteBuffer.order(ByteOrder.nativeOrder());
    updateRaw(floats);
    size = floats.length;
  }
  
  /**
   * Removes the buffer from memory, good practice to use this
   */
  public void free() {
    byteBuffer.clear();
    byteBuffer = null;
  }
  
  /**
   * Updates the BufferObject with a new set of points, passed by a float array.
   * The length of this array must match the size of the BufferObject as it stands.
   * Unexpected results (or Exceptions) will arise if not used properly.
   *  
   * @param floats an array of points for the buffer
   */
  public void updateRaw(float[] floats) {
    byteBuffer.position(0);
    for(int i = 0; i < floats.length; i++) {
      byteBuffer.putFloat(floats[i]);
    }
    byteBuffer.position(0);
  }
  
  /**
   * Updates the BufferObject with a new set of points, assuming rectangular shape.
   * This should only be used in a BufferObject of length 8. Otherwise errors may occur.
   * Merely for convenience, it is wiser to use updateRaw
   * 
   * @param x x-coordinate 
   * @param y y-coordinate 
   * @param width width of rectangle
   * @param height height of rectangle
   */
  public void update(float x, float y, float width, float height) {
    byteBuffer.position(0);
    byteBuffer.putFloat(x);
    byteBuffer.putFloat(y);
    byteBuffer.putFloat(x + width);
    byteBuffer.putFloat(y);
    byteBuffer.putFloat(x);
    byteBuffer.putFloat(y + height);
    byteBuffer.putFloat(x + width);
    byteBuffer.putFloat(y + height);
    byteBuffer.position(0);
  }
  
  /**
   * Returns the ByteBuffer object created by BufferObject
   * 
   * @return ByteBuffer object, NULL if not valid
   */
  public ByteBuffer get() {
    return byteBuffer;
  }
  
}