Android：Renderer的不同的两种用法

Question

我用Renderer两种方式绘制三角形。一个是工作，一个是无。

这是我的两个解决方案。

第一个解决方案：运行时无法工作。我emplements Renderer（你应该看到一行：glView.setRenderer方法我的两个解决方案的基本差异。）

package com.test; 

import java.nio.ByteBuffer; 
import java.nio.ByteOrder; 
import java.nio.FloatBuffer; 

import javax.microedition.khronos.egl.EGLConfig; 
import javax.microedition.khronos.opengles.GL10; 

import android.app.Activity; 
import android.opengl.GLSurfaceView; 
import android.opengl.GLSurfaceView.Renderer; 
import android.os.Bundle; 

public class TriangleOpenGLTest extends Activity implements Renderer{ 

    FloatBuffer vertices; 
    ByteBuffer byteBuffer; 
    GL10 gl; 
    GLSurfaceView glView; 


    @Override 
    public void onCreate(Bundle savedInstanceState){ 

     super.onCreate(savedInstanceState); 

     byteBuffer = ByteBuffer.allocateDirect(3*2*4); 
     byteBuffer.order(ByteOrder.nativeOrder()); 

     vertices = byteBuffer.asFloatBuffer(); 
     vertices.put(new float[] { 0.0f, 0.0f, 319.0f, 0.0f, 160.0f, 479.0f}); 
     vertices.flip(); 

     glView = new GLSurfaceView(this); 
     glView.setRenderer(this); 
     setContentView(glView); 

    } 

    @Override 
    public void onResume(){ 
     super.onResume(); 
      gl.glViewport(0, 0, glView.getWidth(), glView.getHeight()); 
     gl.glClear(GL10.GL_COLOR_BUFFER_BIT); 
      gl.glMatrixMode(GL10.GL_PROJECTION); 
      gl.glLoadIdentity(); 
      gl.glOrthof(0, 320, 0, 480, 1, -1); 
      gl.glColor4f(1, 0, 0, 1); 
      gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); 
      gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertices); 
      gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);  
    } 

      @Override 
     public void onDrawFrame(GL10 gl) { 
     } 

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

     } 

     @Override 
     public void onSurfaceCreated(GL10 gl, EGLConfig config) { 

     } 
} 

解决方案2：我创建了一个新的子类我的渲染器。

package com.test; 

import java.nio.ByteBuffer; 
import java.nio.ByteOrder; 
import java.nio.FloatBuffer; 

import javax.microedition.khronos.egl.EGLConfig; 
import javax.microedition.khronos.opengles.GL10; 

import android.app.Activity; 
import android.opengl.GLSurfaceView; 
import android.opengl.GLSurfaceView.Renderer; 
import android.os.Bundle; 

public class TriangleOpenGLTest extends Activity { 

    FloatBuffer vertices; 
    ByteBuffer byteBuffer; 
    GL10 gl; 
    GLSurfaceView glView; 


    @Override 
    public void onCreate(Bundle savedInstanceState){ 

     super.onCreate(savedInstanceState); 

     byteBuffer = ByteBuffer.allocateDirect(3*2*4); 
     byteBuffer.order(ByteOrder.nativeOrder()); 

     vertices = byteBuffer.asFloatBuffer(); 
     vertices.put(new float[] { 0.0f, 0.0f, 319.0f, 0.0f, 160.0f, 479.0f}); 
     vertices.flip(); 

     glView = new GLSurfaceView(this); 
     glView.setRenderer(new DrawTriangle()); 
     setContentView(glView); 

    } 

    @Override 
    public void onResume(){ 
     super.onResume(); 
    } 

    public class DrawTriangle implements Renderer{ 

     public DrawTriangle(){ 

     } 
     @Override 
     public void onDrawFrame(GL10 gl) { 

      gl.glViewport(0, 0, glView.getWidth(), glView.getHeight()); 
      gl.glClear(GL10.GL_COLOR_BUFFER_BIT); 
      gl.glMatrixMode(GL10.GL_PROJECTION); 
      gl.glLoadIdentity(); 
      gl.glOrthof(0, 320, 0, 480, 1, -1); 
      gl.glColor4f(1, 0, 0, 1); 
      gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); 
      gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertices); 
      gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);  

     } 

     @Override 
     public void onSurfaceChanged(GL10 gl, int width, int height) { 
      // TODO Auto-generated method stub 

     } 

     @Override 
     public void onSurfaceCreated(GL10 gl, EGLConfig config) { 
      // TODO Auto-generated method stub 

     } 

    } 

} 

谁能为我解释两种解决方案之间的区别，请。

谢谢:)

Answer 1

在第一个解决方案，您有一个空onDrawFrame（）方法。这可能是为什么它不起作用。见GLSurfaceView.Renderer