glview.java

Android下的openGL 编程实例

package com.google.android.tunnel3d;

import android.view.*;
import android.content.*;
import android.graphics.*;
import android.opengl.GLU;
import javax.microedition.khronos.opengles.*;
import java.nio.*;


public class GLView extends SurfaceView implements SurfaceHolder.Callback
{
private OpenGLContext ctx;
private Tunnel3D	  tunnel;
private boolean		  created;
private GL10		  gl;
private int			  w;
private int           h;
private Bitmap 		  bmp;
private int           tex;


  public GLView (Context context)
  {
  // Parent...
    super (context);
    getHolder ().setCallback (this);
    
  // Internal members..
    ctx = new OpenGLContext (OpenGLContext.DEPTH_BUFFER);
    gl = (GL10)ctx.getGL ();
    tunnel = new Tunnel3D (10, 20);
    created = false;

  // Enabling the state...
    gl.glEnable (GL10.GL_DEPTH_TEST);
    gl.glEnable (GL10.GL_TEXTURE_2D);
    gl.glEnableClientState (GL10.GL_VERTEX_ARRAY);
    gl.glEnableClientState (GL10.GL_COLOR_ARRAY);
    gl.glEnableClientState (GL10.GL_TEXTURE_COORD_ARRAY);

  // Loading texture...
	bmp = BitmapFactory.decodeResource (context.getResources(), R.drawable.plants03);
    tex = loadTexture (gl, bmp);
  }

  public boolean surfaceCreated (SurfaceHolder holder)
  {
	synchronized (this) 
	  {
	    created = true;
      }
    return true;
  }

  public void surfaceDestroyed (SurfaceHolder holder) 
  {
    synchronized (this) 
	  {
	    created = false;		
  	  }
  }

  public void surfaceChanged (SurfaceHolder holder, int format, int w, int h) 
  {
    synchronized (this) 
	  {
    	this.w = w;
    	this.h = h;
	  }
  }

  public void render ()    
  {
  // Check the created flag...
	boolean c = false;
    synchronized (this) 
      {
    	c = created;
      }	  
	if (!c) return;  

  // Start the surface holder...
	SurfaceHolder sh = getHolder ();
    Canvas g = sh.lockCanvas ();

  // Hooking GL with the view...
    ctx.makeCurrent (g, null);

  // Setting up the projection...
    float ratio = (float)w / h;
    gl.glMatrixMode (GL10.GL_PROJECTION);
    gl.glLoadIdentity ();
    gl.glViewport (0, 0, w, h);
    GLU.gluPerspective (gl, 45.0f, ((float)w)/h, 1f, 100f);

  // Setting up the modelview...
    gl.glMatrixMode (GL10.GL_MODELVIEW);
    gl.glLoadIdentity ();

  // Clear the z-buffer...
    gl.glClear (GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

  // Render the tunnel...    
    tunnel.render (gl, -1.6f);
    tunnel.nextFrame ();

  // OpenGL finish
    gl.glFlush ();
    gl.glFinish ();    

  // Finish with hook
    ctx.waitGL ();

  // End the surface holder...
    sh.unlockCanvasAndPost (g);
  }

  private int loadTexture (GL10 gl, Bitmap bmp) 
  {
		ByteBuffer bb = ByteBuffer.allocateDirect(bmp.height()*bmp.width()*4);
		bb.order(ByteOrder.nativeOrder());
		IntBuffer ib = bb.asIntBuffer();
		
		for (int y=0;y<bmp.height();y++)
			for (int x=0;x<bmp.width();x++) {
					ib.put(bmp.getPixel(x,y));
			}
		ib.position(0);
		bb.position(0);
		
		int[] tmp_tex = new int[1];
		
		gl.glGenTextures(1, tmp_tex, 0);
		int tex = tmp_tex[0];
		gl.glBindTexture(GL10.GL_TEXTURE_2D, tex);
		gl.glTexImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_RGBA, bmp.width(), bmp.height(), 0, GL10.GL_RGBA, GL10.GL_UNSIGNED_BYTE, bb);
		gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
		gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
	
		return tex;
  }
}