Android Open Source - maze-android Texture

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Back to project page maze-android.

License

The source code is released under:

GNU General Public License

Java Source Code

/*
 *  Maze-Android//from  w  ww . j  av a2  s.  co m
 *  Copyright 2009, 2010, 2011, 2012 Marco Mandrioli
 *
 *  This file is part of Maze-Android.
 *
 *  Maze-Android 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.
 *
 *  Maze-Android 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 Maze-Android.  If not, see <http://www.gnu.org/licenses/>.
 *
 */


package it.zavo.maze.graphics;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLUtils;

/**
 * A single 2D texture.
 * 
 * @author Marco Mandrioli
 */
public class Texture {
  private int textureID;
  private int[] texture;

  private FloatBuffer textureBuffer;

  /**
   * Constructs a texture, setting its resource ID.
   * 
   * @param resID
   *            the resource identifier of the drawable file to be used as a
   *            texture.
   */
  public Texture(int resID) {
    textureID = resID;
  }

  /**
   * Binds the texture and its texture coordinates buffer to the gl context.
   * 
   * @param gl
   *            the GL object.
   */
  public void bind(GL10 gl) {
    // binds the texture
    gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]);

    // makes gl point to the texture coordinates buffer
    gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
  }

  /**
   * Loads the texture. This should be called by the
   * {@link Graphics#onSurfaceCreated(GL10 gl, EGLConfig config)
   * onSurfaceCreated(...)}.
   * 
   * @param gl
   *            the GL object.
   * @param context
   *            the context the context in which the drawable resource is.
   * 
   * @see Graphics#onSurfaceCreated(GL10 gl, EGLConfig config)
   */
  public void load(GL10 gl, Context context) {
    float[] textureVertices = {
        0.0f, 0.0f,  // top left vertex
        0.0f, 1.0f,  // bottom left vertex
        1.0f, 0.0f,  // top right vertex
        1.0f, 1.0f  // bottom right vertex
    };

    texture = new int[1];

    // constructs a buffer of bytes to store the texture's vertices array
    // (float = 4 bytes)
    ByteBuffer byteBuf = ByteBuffer
        .allocateDirect(textureVertices.length * 4);
    // sets the byte order to the platform's (Little Endian or Big Endian)
    byteBuf.order(ByteOrder.nativeOrder());
    // converts the byte buffer to a vertex buffer (float)
    textureBuffer = byteBuf.asFloatBuffer();
    // puts the vertices in the texture's vertex buffer
    textureBuffer.put(textureVertices);
    // sets the position of the texture's vertex buffer to the start
    textureBuffer.position(0);

    // opens the input stream of the texture's resource from the resource ID
    InputStream is = context.getResources().openRawResource(textureID);
    // decodes the input stream to a bitmap
    Bitmap bitmap = BitmapFactory.decodeStream(is);

    // closes input stream
    try {
      is.close();
      is = null;
    } catch (IOException e) {
      e.printStackTrace();
    }

    // generates the texture
    gl.glGenTextures(1, texture, 0);
    // binds the texture
    gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]);

    // creates nearest filtered texture
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
        GL10.GL_NEAREST);
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
        GL10.GL_LINEAR);

    // sets the texture parameters
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
        GL10.GL_CLAMP_TO_EDGE);
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
        GL10.GL_CLAMP_TO_EDGE);

    // determines the internalFormat and type of the bitmap
    GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);

    // frees the native object associated to the bitmap
    bitmap.recycle();
  }
}

Java Source Code List

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