openGL简例2

public class VortexRenderer implements GLSurfaceView.Renderer{

private float _red = 0.9f;
private float _green = 0.8f;
private float _blue = 0.8f;
// new object variables we need
// a raw buffer to hold indices
private ShortBuffer _indexBuffer;
private ShortBuffer _indexBufferStatic;
// a raw buffer to hold the vertices
private FloatBuffer _vertexBuffer;
private FloatBuffer _vertexBufferStatic;
private short[] _indicesArray = {0, 1, 2};
private int _nrOfVertices = 3;
// code snipped
private float _angle;
private FloatBuffer _colorBuffer;
private float _xAngle;
private float _yAngle;
private float _width = 320f;
private float _height = 480f;
public void setAngle(float angle) {
_angle = angle;
}
private void initTriangle() {
    // float has 4 bytes
    ByteBuffer vbb = ByteBuffer.allocateDirect(_nrOfVertices * 3 * 4);
    vbb.order(ByteOrder.nativeOrder());
    _vertexBuffer = vbb.asFloatBuffer();
    // short has 2 bytes
    ByteBuffer ibb = ByteBuffer.allocateDirect(_nrOfVertices * 2);
    ibb.order(ByteOrder.nativeOrder());
    _indexBuffer = ibb.asShortBuffer();
    // float has 4 bytes, 4 colors (RGBA) * number of vertices * 4 bytes
    ByteBuffer cbb = ByteBuffer.allocateDirect(4 * _nrOfVertices * 4);
    cbb.order(ByteOrder.nativeOrder());
    _colorBuffer = cbb.asFloatBuffer();
    float[] coords = {
        -0.5f, -0.5f, 0f, // (x1, y1, z1)
        0.5f, -0.5f, 0f, // (x2, y2, z2)
        0f, 0.5f, 0f // (x3, y3, z3)
    };
    float[] colors = {
            1f, 0f, 0f, 1f, // point 1
            0f, 1f, 0f, 1f, // point 2
            0f, 0f, 1f, 1f, // point 3
        };
    _vertexBuffer.put(coords);
    _indexBuffer.put(_indicesArray);
    _colorBuffer.put(colors);
    _vertexBuffer.position(0);
    _indexBuffer.position(0);
    _colorBuffer.position(0);
}

    public void setColor(float r, float g, float b) {
        _red = r;
        _green = g;
        _blue = b;
    }

@Override
public void onDrawFrame(GL10 gl) {

gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
for (int i = 1; i <= 10; i++)
{
gl.glLoadIdentity();
    gl.glTranslatef(0.0f, -1f, -1.0f + -1.5f * i);
// set rotation
gl.glRotatef(_xAngle, 1f, 0f, 0f);
gl.glRotatef(_yAngle, 0f, 1f, 0f);
        // set rotation for the non-static triangle
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, _vertexBuffer);
        gl.glColorPointer(4, GL10.GL_FLOAT, 0, _colorBuffer);
        gl.glDrawElements(GL10.GL_TRIANGLES, _nrOfVertices, GL10.GL_UNSIGNED_SHORT, _indexBuffer);
}
}
@Override
public void onSurfaceChanged(GL10 gl, int w, int h) {
// TODO Auto-generated method stub
_width = w;
_height = h;
gl.glViewport(0, 0, w, h);
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig arg1) {
// TODO Auto-generated method stub
    gl.glMatrixMode(GL10.GL_PROJECTION);
    float size = .01f * (float) Math.tan(Math.toRadians(45.0) / 2);
    float ratio = _width / _height;
    // perspective:
    gl.glFrustumf(-size, size, -size / ratio, size / ratio, 0.01f, 100.0f);
    // orthographic:
    //gl.glOrthof(-1, 1, -1 / ratio, 1 / ratio, 0.01f, 100.0f);
    gl.glViewport(0, 0, (int) _width, (int) _height);
    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glEnable(GL10.GL_DEPTH_TEST);

// define the color we want to be displayed as the "clipping wall"
gl.glClearColor(_red, _green, _blue, 1.0f);
    // enable the differentiation of which side may be visible
    gl.glEnable(GL10.GL_CULL_FACE);
    // which is the front? the one which is drawn counter clockwise
    gl.glFrontFace(GL10.GL_CCW);
    // which one should NOT be drawn
    gl.glCullFace(GL10.GL_BACK);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
    initJZT();
}
}