我如何让glMapBufferRange（）在后台运行

Question

我正在编写一个Android应用程序以捕获屏幕数据，并从中制作MP4。第一步是使用一些openGL调用从屏幕上读出像素。

private void screenScrape() {

    Log.d(TAG, "In screenScrape");

    //read pixels from frame buffer into PBO (GL_PIXEL_PACK_BUFFER)
    mySurface.queueEvent(new Runnable() {
        @Override
        public void run() {

            Log.d(TAG, "In Screen Scrape 1");

            //generate and bind buffer ID
            GLES30.glGenBuffers(1, pboIds);
            checkGlError("Gen Buffers");

            GLES30.glBindBuffer(GLES30.GL_PIXEL_PACK_BUFFER, pboIds.get(0));
            checkGlError("Bind Buffers");

            //creates and initializes data store for PBO.  Any pre-existing data store is deleted
            GLES30.glBufferData(GLES30.GL_PIXEL_PACK_BUFFER, (mWidth * mHeight * 4), null, GLES30.GL_STATIC_READ);
            checkGlError("Buffer Data");

            glReadPixelsPBO(0, 0, mWidth, mHeight, GLES30.GL_RGBA, GLES30.GL_UNSIGNED_BYTE, 0);
            checkGlError("Read Pixels");
        }
    });

    //map PBO data into client address space
    mySurface.queueEvent(new Runnable() {
        @Override
        public void run() {
            Log.d(TAG, "In Screen Scrape 2");

            //read pixels from PBO into a byte buffer for processing.  Unmap buffer for use in next pass
            mapBuffer = ((ByteBuffer) GLES30.glMapBufferRange(GLES30.GL_PIXEL_PACK_BUFFER, 0, 4 * mWidth * mHeight, GLES30.GL_MAP_READ_BIT)).order(ByteOrder.nativeOrder());
            checkGlError("Map Buffer");

            GLES30.glUnmapBuffer(GLES30.GL_PIXEL_PACK_BUFFER);
            checkGlError("Unmap Buffer");


            //openGL calls return pixels in a flipped format.  Flip buffer so image presented right side up
            for (int i = 0; i < mWidth; ++i) {
                for (int j = 0; j < mHeight; ++j) {
                    for (int k = 0; k < 4; ++k) {
                        flippedBuffer.put((i + j * mWidth) * 4 + k, mapBuffer.get((i + (mHeight - 1 - j) * mWidth) * 4 + k));
                    }
                }
            }

            isByteBufferEmpty(mapBuffer, "MAP BUFFER");
            Log.d(TAG, "Flipped Buffer Position: " + flippedBuffer.position() + "Remaining: " + flippedBuffer.remaining() + " Limit: " + flippedBuffer.limit());
            convertColorSpaceByteArray(flippedBuffer);
            mapBuffer.clear();
        }
    });
}

mySurface是我从输入参数初始化的GLMapsurface。

例如GLMapSurface mySurface = inputSurface，其中inputSurface是传递的参数。

现在，我的问题是对glMapBufferRange的调用会阻止UI。如何让此调用在后台线程中运行，从而不会阻塞UI？

我试图创建一个新的GLMapSurface对象并将事件排队，但是它们从未执行。