Copy opal.cpp here to make this emulator available.
This is not distributed with the software while the license is undetermined.

The opal.cpp file is part of REALITY ADLIB TRACKER V2.
SHA1: c034dd637887d81770cee92da309fc547ef5fe18

Configure the software with the option USE_OPAL_EMULATOR=ON.
To enable soft panning, it is needed to patch with the file `opal-pan.diff` provided.
for example: `patch -p0 -i opal-pan.diff`