what is wrong when i use Eglimage replace glreadpixels in NDK program?

Question

//step 2. Create the Android Graphic Buffer
GraphicBuffer* buffer = new GraphicBuffer(w, h,
   HAL_PIXEL_FORMAT_RGBA_8888,
   GraphicBuffer::USAGE_HW_TEXTURE |
   Gr         


        

Answer 1

You need a glFinish() call to tell the driver to do the actual drawing. The glReadPixels() call is causing things to work because it forces the rendering to happen -- you've told the driver that you want to read the pixels back, so it pauses until rendering is complete.