如何在android上使用opengl es 2.0显示屏幕截图的模糊位图？

Question

我正在尝试使用opengl es 2.0在android中创建一个应用程序，该应用程序有一个按下按钮，它将截取屏幕截图并使用任何模糊算法（此处为快速模糊）对其进行模糊处理，并显示模糊的屏幕截图。开发这样一个应用程序的唯一目的是尝试和实现模糊。使用各种互联网资源，我能够截取屏幕截图并实现模糊，但我不知道如何在 opengl 的屏幕上显示模糊的位图。谁能帮我解决这个问题？提前致谢。 以下是我的主要活动：

package com.example.ankurtest;

import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

public class MainActivity extends Activity {
GLSurfaceView mView;
GLRendererEX myRenderer;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //setContentView(mView);
    mView = (MyGLSurfaceview)findViewById(R.id.glSurfaceViewID);
    myRenderer = new GLRendererEX(this);

    mView.setEGLContextClientVersion(2);
    mView.setRenderer(myRenderer);
    myRenderer.queueDoSomethingNextTick(GLRendererEX.DO_THIS);

    findViewById(R.id.buttonID).setOnTouchListener(new OnTouchListener(){

       /* public void onTouch(MotionEvent event){
            myRenderer.queueDoSomethingNextTick(GLRendererEX.DO_THAT);
           // Compiler might complain about myRenderer not being final
        }*/

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if(event.getAction() == MotionEvent.ACTION_UP){
            myRenderer.queueDoSomethingNextTick(GLRendererEX.DO_THAT);
            return true;
            }
            return false;
        }
});
}

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    mView.onPause();
}

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    mView.onResume();
}

    }

以下是我的 MyGLsurfaceview 类：

package com.example.ankurtest;

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.util.AttributeSet;

public class MyGLSurfaceview extends GLSurfaceView {

//private final GLRendererEX mRenderer;

public MyGLSurfaceview(Context context) {
    super(context);

    // Create an OpenGL ES 2.0 context.
    //setEGLContextClientVersion(2);

    // Set the Renderer for drawing on the GLSurfaceView
    //mRenderer = new GLRendererEX();
    //setRenderer(mRenderer);

    // Render the view only when there is a change in the drawing data
    setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
}
public MyGLSurfaceview(Context context, AttributeSet attrs)
{
  super(context, attrs);

  // Create an OpenGL ES 2.0 context.
  setEGLContextClientVersion(2);

  // Set the Renderer for drawing on the GLSurfaceView
  //mRenderer = new GLRendererEX();
  //setRenderer(mRenderer);
}

}

以下是我的渲染器类：

package com.example.ankurtest;

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

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

import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Point;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView.Renderer;
import android.os.Build;
import android.view.Display;
import android.view.WindowManager;

@TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
public class GLRendererEX implements Renderer{

private final Context context;

private int command;
public static final int DO_THIS = 1;
public static final int DO_THAT = 2;


public GLRendererEX(Context activitycontext) {
    context = activitycontext;

}


public void onSurfaceCreated(GL10 gl, EGLConfig config) {
    GLES20.glClearColor(0.8f, 0.0f, 0.2f, 1f);

    // TODO Auto-generated method stub

}
@Override
public void onDrawFrame(GL10 gl) {

    if (command==DO_THAT) {
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);

        Point size = new Point();
        WindowManager wm = (WindowManager)  context.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        //myactivity.getWindowManager().getDefaultDisplay().getSize(size);
        display.getSize(size);
        int width = size.x; // use your favorite width
        int height = size.y; // use your favorite height
        int screenshotSize = width * height;
        ByteBuffer bb = ByteBuffer.allocateDirect(screenshotSize * 4);
        bb.order(ByteOrder.nativeOrder());
        GLES20.glReadPixels(0, 0, width, height, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, bb);
        int pixelsBuffer[] = new int[screenshotSize];
        bb.asIntBuffer().get(pixelsBuffer);
        bb = null;

        for (int i = 0; i < screenshotSize; ++i) {
            // The alpha and green channels' positions are preserved while the      red and blue are swapped
            pixelsBuffer[i] = ((pixelsBuffer[i] & 0xff00ff00)) |    ((pixelsBuffer[i] & 0x000000ff) << 16) | ((pixelsBuffer[i] & 0x00ff0000) >> 16);
        }

        Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        bitmap.setPixels(pixelsBuffer, screenshotSize-width, -width, 0, 0, width, height);
Bitmap fast = Fastblur(bitmap,10);
        command = DO_THIS;
    }
    // TODO Auto-generated method stub

}

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

}

public void queueDoSomethingNextTick(int command){

    this.command = command;

}

}

这里使用Fastblur()方法对截图进行模糊处理，返回模糊后的截图。现在，我的问题是如何使用 opengl 显示 Fastblur() 返回的位图？

Answer 1

显示全尺寸图像的常用方法是使用正交投影矩阵：

（使用固定功能的示例）

GLES20.glViewport(0, 0, windowWidth, windowHeight);
GLES20.glMatrixMode(GL_PROJECTION);
GLES20.glLoadIdentity();
GLES20.glOrtho(-1, 1, -1, 1, 1, -1);

而不是绘制一个将图像绑定为 texture2D 的全屏四边形。

纹理基础教程here.

基本四边形教程here。

设置四边形坐标如下：

static float squareCoords[] = {
        -1f, -1f, 0.0f,   // top left
        -1f, 1f, 0.0f,   // bottom left
         1f, 1f, 0.0f,   // bottom right
         1f, -1f, 0.0f }; // top right