1
我用Renderer
兩種方式繪製三角形。一個是工作,一個是無。Android:Renderer的不同的兩種用法
這是我的兩個解決方案。
第一個解決方案:運行時無法工作。我emplements Renderer
(你應該看到一行:glView.setRenderer
方法我的兩個解決方案的基本差異。)
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) {
}
}
解決方案2:我創建了一個新的子類我的渲染器。
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
}
}
}
誰能爲我解釋兩種解決方案之間的區別,請。
謝謝:)
哦。非常感謝。你能否爲我解釋一下這個例子中onResume和onDrawFrame之間的區別。因爲我認爲Android會像onDrawFrame一樣運行onResume。謝謝:) – hqt 2012-02-17 14:24:39
當onResume被觸發時,這會告訴GLSurfaceView開始反覆調用onDrawFrame()。由於你的第一個方法在onDrawFrame函數中什麼也沒做,所以沒有任何東西在繪製。如果你把你在onResume函數中的繪製代碼放到onDrawFrame()中,它應該開始工作。注意onResume只被調用一次,至少直到不同的生命週期事件引發循環更改(記錄並查看)爲止。有關android生命週期的更多信息,請參閱[Activity Life Cycle](http://developer.android.com/reference/android/app/Activity.html#ActivityLifecycle) – Maz 2012-02-18 07:19:09