Android OpenGL ES：红色三角形

 1 public class MyRenderer implements Renderer 
 2 {
 3     FloatBuffer verticesBuffer;
 4 
 5     @Override
 6     public void onDrawFrame(GL10 gl) 
 7     {
 8         gl.glViewport(0, 0, 320, 480);
 9         gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
10         gl.glMatrixMode(GL10.GL_PROJECTION);
11         gl.glLoadIdentity();
12         gl.glOrthof(0, 320, 0, 480, 1, -1);
13         
14         gl.glColor4f(1, 0, 0, 1);
15         gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
16         gl.glVertexPointer(2, GL10.GL_FLOAT, 0, verticesBuffer);
17         gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
18     }
19 
20     @Override
21     public void onSurfaceChanged(GL10 gl, int width, int height) 
22     {
23 
24     }
25 
26     @Override
27     public void onSurfaceCreated(GL10 gl, EGLConfig config) 
28     {
29         ByteBuffer byteBuffer = ByteBuffer.allocateDirect(3 * 2 * 4); // 3:顶点数 2:维数,x和y 4:一个float型占4个字节
30         byteBuffer.order(ByteOrder.nativeOrder());
31         verticesBuffer = byteBuffer.asFloatBuffer();
32         verticesBuffer.put(new float[] {0, 0,
33                 320, 0,
34                 160, 480});
35         verticesBuffer.flip();
36     }
37 }

// Activity:
public class OpenGLTestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        GLSurfaceView glSurfaceView = new GLSurfaceView(this);
        MyRenderer renderer = new MyRenderer();
        glSurfaceView.setRenderer(renderer);
        setContentView(glSurfaceView);
    }
}