In my project I am using egl library to plot a 3D object to the display and concurrently saving the image in a file or an area of memory.
I'm trying to use eglCopyBuffers() to copy a surface to a pixmap in order to obtain the pixel value that are displayed. I'm using an ARM MALI architecture and I would not want to use X11 but writing directly to GNU/Linux framebuffer.
I have few questions:
1)In my method, I pass to eglCopyBuffers function, as 'native_pixmap' parameter, an 'EGLNativePixmapType native_pixmap= NULL'. Is it correct? If I try to allocate a Pixmap (X11 dependent) before calling eglCopyBuffers the system crashes. How should I declare the pixmap if I do not want to use X11 libraries?
In addition, if I do as above, eglCopyBuffers returns an EGL_FALSE error, which means that the swapping of the surface buffers fails.
2) Is there another simpler method to obtain the image displayed in framebuffer? Should I directly read data from /dev/fb0? I read about the method glReadPixel but it is described as being slow and X11 dependent.
Thank you in advance for your advice.