glReadPixelsからBitmapへの画像取得

gistfile1.java

        // ByteBufferに読み込み
        ByteBuffer buffer = ByteBuffer.allocateDirect(width * height * 4);
        gl10.glReadPixels(0, 0, width, height, GL10.GL_RGBA, GL10.GL_UNSIGNED_BYTE, buffer);

        // 上下逆なので、上下反転
        byte[] tmp1 = new byte[width * 4];
        byte[] tmp2 = new byte[width * 4];
        int h = (int) height / 2;
        for (int y = 0; y < h; y++) {
            buffer.position(y * width * 4);
            buffer.get(tmp1, 0, tmp1.length);
            buffer.position((height - 1 - y) * width * 4);
            buffer.get(tmp2, 0, tmp2.length);
            buffer.position((height - 1 - y) * width * 4);
            buffer.put(tmp1);
            buffer.position(y * width * 4);
            buffer.put(tmp2);
        }
        buffer.position(0);
        tmp1 = tmp2 = null;

        // Bitmapの作成
        Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        bitmap.copyPixelsFromBuffer(buffer);

        // 後片付け
        buffer = null;
        System.gc();