Ravencoin coin mining is currently mined on video cards using the following programs:
sgminer-x16r;
RavenMiner;
ccminer;
Z-Enemy-CUDA;
T-Rex.
Most of them are open source. You can take them as an example for your program.
I'm curently looking at the source for RavenMiner but I'll check those out too.

You can try the Z-enemy it gives me higher hashrate compared to other mining software.
You can find the z-enemy here in the forum.
You can check their official thread here
https://bitcointalk.org/index.php?topic=3378390.0