How do you convert opengl texture back to bitmap in android?

问题

I wanted to apply image-filter to my image and used android HelloEffects sample

It converts the image data from bitmap to texture.
After applying the image filter effect, I'd like to get the image back in jpeg format, but don't know how to do that.

回答1:

Check the saveFrame() method mentioned in http://bigflake.com/mediacodec/ExtractMpegFramesTest_egl14.java.txt

回答2:

I did this in one way like ,

1. I converted the texture image into bitmap using glreadpixles() method

2. I then saved the bitmap to the sd card

Texture to bitmap code

public static Bitmap SavePixels(int x, int y, int w, int h){
    int b[]=new int[w*(y+h)];
    int bt[]=new int[w*h];
    IntBuffer ib = IntBuffer.wrap(b);
    ib.position(0);
    GLES20.glReadPixels(0, 0, w, h, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, ib);

    for(int i=0, k=0; i<h; i++, k++)
    {//remember, that OpenGL bitmap is incompatible with Android bitmap
        //and so, some correction need.
        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);
    return sb;
}

Bitmap to internal storage code,

 public  static void saveImage(Bitmap finalBitmap) {

    File myDir=new File("/sdcard/saved_images");
    myDir.mkdirs();
    Random generator = new Random();
    int n = 10000;
    n = generator.nextInt(n);
    String fname = "Image-"+ n +".jpg";
    File file = new File (myDir, fname);
    if (file.exists ()) file.delete ();
    try {
        FileOutputStream out = new FileOutputStream(file);
        finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
        out.flush();
        out.close();

    } catch (Exception e) {
        e.printStackTrace();
    }
}

来源：https://stackoverflow.com/questions/24421290/how-do-you-convert-opengl-texture-back-to-bitmap-in-android