Android Open Source - agldemo Lesson09

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License

The source code is released under:

Copyright (c) 2013 Wenhao Li Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software...

Java Source Code

/**
 * Copyright (C) 2010 Wenhao Li. All Rights Reserved.
 * //from ww  w  .j  ava  2  s  . c  o  m
 */
package com.agldemo.lessons;

import java.nio.FloatBuffer;

import javax.microedition.khronos.opengles.GL10;

import com.agldemo.Lesson;
import com.agldemo.R;

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

/**
 * Lesson 09
 */
public class Lesson09 extends Lesson {

  FloatBuffer quad = makeFloatBuffer(new float[] {
      //
      -1.0f, -1.0f, 1.0f,
      //
      1.0f, -1.0f, 1.0f,
      //
      1.0f, 1.0f, 1.0f,
      //
      -1.0f, 1.0f, 1.0f, });

  FloatBuffer qtex = makeFloatBuffer(new float[] {
      //
      0.0f, 1.0f,
      //
      1.0f, 1.0f,
      //
      1.0f, 0.0f,
      //
      0.0f, 0.0f, });

  float zoom = -15.0f;
  float tilt = 90.0f;
  float spin = 0.0f;

  private Bitmap mBitmap;

  int texture = -1;

  private class Star {
    public float r, g, b;
    public float dist;
    public float angle;
  };

  private Star stars[] = new Star[25];

  public Lesson09(Context c) {
    super(c, "Lesson 09", "Moving Bitmaps In 3D Space");
    mBitmap = BitmapFactory.decodeResource(c.getResources(), R.drawable.star);  

    for (int i = 0; i < stars.length; i++) {
      stars[i] = new Star();
      stars[i].angle = 0.0f;
      stars[i].dist = ((float) i / stars.length) * 5.0f;
      stars[i].r = (float) Math.random();
      stars[i].g = (float) Math.random();
      stars[i].b = (float) Math.random();
    }
  }

  public void onDrawFrame(GL10 gl, int width, int height) {
    float ratio = (float) width / height;
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();
    GLU.gluPerspective(gl, 45.0f, ratio, 0.1f, 100.0f);

    // texture
    if (texture == -1) {
      texture = loadTexture(gl, mBitmap);
    }
    gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);
    gl.glEnable(GL10.GL_TEXTURE_2D);

    // blend
    gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE);
    gl.glEnable(GL10.GL_BLEND);

    // draw
    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glLoadIdentity();

    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, quad);
    gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, qtex);

    for (int i = 0; i < stars.length; i++) {
      gl.glLoadIdentity();
      gl.glTranslatef(0.0f, 0.0f, zoom);

      gl.glRotatef(tilt, 1.0f, 0.0f, 0.0f);
      gl.glRotatef(stars[i].angle, 0.0f, 1.0f, 0.0f);

      gl.glTranslatef(stars[i].dist, 0.0f, 0.0f);

      gl.glRotatef(-stars[i].angle, 0.0f, 1.0f, 0.0f);
      gl.glRotatef(-tilt, 1.0f, 0.0f, 0.0f);
      gl.glRotatef(spin, 0.0f, 0.0f, 1.0f);

      gl.glColor4f(stars[i].r, stars[i].g, stars[i].b, 1.0f);

      gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 4);

      spin += 0.01f;
      stars[i].angle += (float) i / stars.length;
      stars[i].dist -= 0.01f;

      if (stars[i].dist < 0.0f) {
        stars[i].dist += 5.0f;
        stars[i].r = (float) Math.random();
        stars[i].g = (float) Math.random();
        stars[i].b = (float) Math.random();
      }
    }

    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

    // clean up
    gl.glDisable(GL10.GL_TEXTURE_2D);
    gl.glDisable(GL10.GL_BLEND);
    gl.glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
  }
}

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