This example performs some simple OpenCL operations on camera or video input
which is assumed to be provided in RGB format. The OpenCL operation is done on
an OpenGL texture using CL-GL interop, without any further readbacks or copies
(except for the initial texture upload, when necessary).

Currently OS X, Windows with real OpenGL (opengl32.dll) and Linux (GLX only) are
supported. Note that an OpenCL implementation with GPU support is required. The
platform and device selection logic supports NVIDIA, AMD and Intel. Porting to
other platforms is probably simple, see clCreateContextFromType.

On Windows you may need to edit testplugin.pro to specify the location of the
OpenCL headers and libraries.

YUV formats are not supported in this example. This is probably not an issue an
OS X and Windows, but will most likely disable the example on Linux.

Pass the name of a video file to perform video playback or launch without
arguments to use the camera.