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openGL线s的绘制

/**  

* 缓冲区工具类  

*/

public class BufferUtil {  

/**  

* 将浮点数组转换成字节缓冲区  

*/  

public static ByteBuffer arr2ByteBuffer(float[] arr){   

ByteBuffer ibb = ByteBuffer.allocateDirect(arr.length * 4);

  ibb.order(ByteOrder.nativeOrder());

  FloatBuffer fbb = ibb.asFloatBuffer();  

 fbb.put(arr);  

 ibb.position(0);  

 return ibb ;  

}    

/**  

* 将list转换成字节缓冲区  

*/

 public static ByteBuffer list2ByteBuffer(List<Float> list){

  ByteBuffer ibb = ByteBuffer.allocateDirect(list.size() * 4);

  ibb.order(ByteOrder.nativeOrder());   

FloatBuffer fbb = ibb.asFloatBuffer();  

 for(Float f : list){  

  fbb.put(f);   

}  

 ibb.position(0);  

 return ibb ;  

}

}

 

/**  

* 渲染器

 */

public abstract class AbstractMyRenderer implements android.opengl.GLSurfaceView.Renderer

{  

 private float ratio;  

  public float xrotate = 0f;//围绕x轴旋转角度

public float yrotate = 0f;//围绕x轴旋转角度  

 /**

  * 1.

  */  

public void onSurfaceCreated(GL10 gl, EGLConfig config)

{  

 //清平色  

 gl.glClearColor(0f, 0f, 0f, 1f);   

//启用顶点缓冲区数组

  gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);  

}

/**  

* 2.

  */

 public void onSurfaceChanged(GL10 gl, int width, int height) {

//设置视口

  gl.glViewport(0, 0, width, height);   

ratio = (float)width / (float)height;   

//投影矩阵  

 gl.glMatrixMode(GL10.GL_PROJECTION);

  //加载单位矩阵  

 gl.glLoadIdentity();  

 //设置平截头体   

gl.glFrustumf(-ratio, ratio, -1, 1, 3f, 7f);  }

/**

  * 3.

  */  

public abstract void onDrawFrame(GL10 gl);

}

 

public class MyLinesRenderer extends AbstractMyRenderer{

 public void onDrawFrame(GL10 gl) {   

//清除颜色缓冲区  

 gl.glClear(GL10.GL_COLOR_BUFFER_BIT);   

//设置绘图颜色

  gl.glColor4f(1f, 0f, 0f, 1f);   

  //操作模型视图矩阵  

 gl.glMatrixMode(GL10.GL_MODELVIEW);  

 gl.glLoadIdentity();

  //设置眼球的参数  

 GLU.gluLookAt(gl,0f,0f,5f, 0f, 0f, 0f, 0f,1f,0f);      

//旋转角度

  gl.glRotatef(xrotate, 1, 0, 0);   

gl.glRotatef(yrotate, 0, 1, 0);     

 //计算点坐标   

float r = 0.5f ;

//半径  

 float x = 0f,y = 0f,z = 0f ;      

List<Float> coordsList = new ArrayList<Float>();      

//循环绘制点  

 for(float alpha = 0f ; alpha < Math.PI * 6 ; alpha = (float) (alpha + Math.PI / 16)){  

  x = (float) (r * Math.cos(alpha));    

y = (float) (r * Math.sin(alpha));    

coordsList.add(0f);    

coordsList.add(0f);    

coordsList.add(0f);    

   coordsList.add(x);   

 coordsList.add(y);   

 coordsList.add(z);   

}

 gl.glVertexPointer(3, GL10.GL_FLOAT, 0, BufferUtil.list2ByteBuffer(coordsList));

  gl.glDrawArrays(GL10.GL_LINES, 0, coordsList.size() / 3);

    }

}

 

/**

*程序的主入口

*/

public class MainActivity extends Activity {

     private AbstractMyRenderer render;  

private MyGLSurfaceView view;

 public void onCreate(Bundle savedInstanceState) {

 super.onCreate(savedInstanceState);        

view = new GLSurfaceView(this);        

render = new MyTriangleRenderer();        

view.setRenderer(render);        

//GLSurfaceView.RENDERMODE_CONTINUOUSLY:持续渲染(默认)        

//GLSurfaceView.RENDERMODE_WHEN_DIRTY:脏渲染,命令渲染        

view.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);        

setContentView(view);    

}

public boolean onKeyDown(int keyCode, KeyEvent event) {

float step = 5f ;    

 //up      

if(keyCode == KeyEvent.KEYCODE_DPAD_UP){       

render.xrotate = render.xrotate - step ;      

} else if(keyCode == KeyEvent.KEYCODE_DPAD_DOWN){    

  render.xrotate = render.xrotate + step ;    

 }  else if(keyCode == KeyEvent.KEYCODE_DPAD_LEFT){ 

 render.yrotate = render.yrotate + step ;

 }      else if(keyCode == KeyEvent.KEYCODE_DPAD_RIGHT){    

  render.yrotate = render.yrotate - step ;    

 }      

//请求渲染,和脏渲染配合使用      

view.requestRender();      

return super.onKeyDown(keyCode, event);    

}

}