Android源$ C ​​$ C不工作，通过glReadPixels读取帧缓冲区 [英] Android source code not working, reading frame buffer through glReadPixels

问题描述

我是新Android开发，并有转让的指定时间间隔后读取帧缓冲数据。

I am new to Android development and have an assignment to read frame buffer data after a specified interval of time.

我想出了以下code：

I have come up with the following code:

public class mainActivity extends Activity {
    Bitmap mSavedBM;
    private EGL10 egl;
    private EGLDisplay display;
    private EGLConfig config;    
    private EGLSurface surface;
    private EGLContext eglContext;
    private GL11 gl;
    protected int width, height;


 //Called when the activity is first created. 
@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);

    // get the screen width and height
    DisplayMetrics dm = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(dm);
    int screenWidth = dm.widthPixels;
    int screenHeight = dm.heightPixels; 

    String SCREENSHOT_DIR = "/screenshots";
    initGLFr(); //GlView initialized.
    savePixels( 0, 10, screenWidth, screenHeight, gl); //this gets the screen to the mSavedBM.
    saveBitmap(mSavedBM, SCREENSHOT_DIR, "capturedImage");

    //Now we need to save the bitmap (the screen capture) to some location.
    setContentView(R.layout.main); //This displays the content on the screen

}
private void initGLFr()
{
    egl = (EGL10) EGLContext.getEGL();
    display = egl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
    int[] ver = new int[2];
    egl.eglInitialize(display, ver);

    int[] configSpec = {EGL10.EGL_NONE};
    EGLConfig[] configOut = new EGLConfig[1];
    int[] nConfig = new int[1];
    egl.eglChooseConfig(display, configSpec, configOut, 1, nConfig);
    config = configOut[0];
    eglContext = egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT, null);
    surface = egl.eglCreateWindowSurface(display, config, SurfaceHolder.SURFACE_TYPE_GPU, null);
    egl.eglMakeCurrent(display, surface, surface, eglContext);
    gl = (GL11) eglContext.getGL();
}
public void savePixels(int x, int y, int w, int h, GL10 gl)
{
    if (gl == null)
            return;

     synchronized (this) {
     if (mSavedBM != null) {
     mSavedBM.recycle();
     mSavedBM = null;
     }
     }

    int b[] = new int[w * (y + h)];
    int bt[] = new int[w * h];
    IntBuffer ib = IntBuffer.wrap(b);
    ib.position(0);
    gl.glReadPixels(x, 0, w, y + h, GL10.GL_RGBA,GL10.GL_UNSIGNED_BYTE,ib);

    for (int i = 0, k = 0; i < h; i++, k++)
    {
        //OpenGLbitmap is incompatible with Android bitmap
        //and so, some corrections need to be done.
            for (int j = 0; j < w; j++)
            {
                    int pix = b[i * w + j];
                    int pb = (pix >> 16) & 0xff;
                    int pr = (pix << 16) & 0x00ff0000;
                    int pix1 = (pix & 0xff00ff00) | pr | pb;
                    bt[(h - k - 1) * w + j] = pix1;
            }
    }

    Bitmap sb = Bitmap.createBitmap(bt, w, h, Bitmap.Config.ARGB_8888);
    synchronized (this)
    {
        mSavedBM = sb;
    }
} 

static String saveBitmap(Bitmap bitmap, String dir, String baseName) {
    try {
        File sdcard = Environment.getExternalStorageDirectory();
        File pictureDir = new File(sdcard, dir);
        pictureDir.mkdirs();
        File f = null;
        for (int i = 1; i < 200; ++i) {
            String name = baseName + i + ".png";
            f = new File(pictureDir, name);
            if (!f.exists()) {
                break;
            }
        }
        if (!f.exists()) {
            String name = f.getAbsolutePath();
            FileOutputStream fos = new FileOutputStream(name);
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
            fos.flush();
            fos.close();
            return name;
        }
    } catch (Exception e) {

    } finally {

        //if (fos != null) {
         //   fos.close();
       // }

    }
    return null;
}

}

另外，如果有一个人能告诉我到更好的方式来读取帧缓冲区将是巨大的。我使用Android 2.2及API 8级的虚拟设备。
我经历了很多previous讨论了，并发现我们不能直接通过的/ dev /图形/ FB0读取帧缓冲区。

Also, if some one can direct me to better way to read the framebuffer it would be great. I am using Android 2.2 and virtual device of API level 8. I have gone through many previous discussions and have found that we can not read frame buffer directly through the "/dev/graphics/fb0".

（编辑：格式化code的第一行）

(edit: reformatting first lines of code)

推荐答案

问题解决了，关于上述code的执行。但我仍然无法读取帧缓冲数据。

problem solved, regarding the execution of the above code. But still I could not read the frame buffer data.

我深入研究了的内部并追查有关旧版Android pre 1.5帧缓冲访问所有的previous索赔。

I have researched in depth the internals and traced all the previous claims about accessing framebuffer on older versions of Android pre 1.5.

在Android pre 1.5移植确实对直接通过的/ dev / fb0设备访问framebuffer的帖子。这不适合于更新的版本和Android开发团队已经在谷歌Android组提到他们没有计划。

The porting on Android pre 1.5 does have posts on accessing framebuffer directly through /dev/fb0. This does not work for later versions and the Android Development team has no plans as mentioned by them in android google groups.

我希望这可以帮助很多人花了很多的时间来想出一个办法。

I hope this helps a lot of people spending a lot of their time to figure out a way.

问候，
阿里

这篇关于Android源$ C ​​$ C不工作，通过glReadPixels读取帧缓冲区的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！