So since I got steam a few years ago, I've been curious how to get the steam overlay on it. It used to be as simple as adding the non-steam game to your library, however now, it's not so simple. But there is a way. And there's a way to do it for FTB! That's what I'll be showing first.First off, go into your steam library directory in your Browser. (Typically c:/program files (x86)/steam/steamapps/common)
Make a new folder called Minecraft and copy your FTB Launcher.exe there.
Now you'll need to add the game to your library, but you won't add the launcher directly!
Go to C:/Program Files/Java/jre7/bin and look for a javaw.exe file. You'll want to add this to your stream library by adding a non-steam supported game.
DON'T RUN IT.
Now you'll need to right-click javaw.exe in your library and select properties.
Go into your browser again and SHIFT-right click your FTB launcher and click "Copy as path"
In the 'Target' text field you should have "C:\Program Files\Java\jre7\bin\javaw.exe" in quotes. Type in " -jar " at the end and then paste in the path you just copied. If done right, you should have this in your 'Target' text field:
Code:
"C:\Program Files\Java\jre7\bin\javaw.exe" -jar "C:\Program Files (x86)\Steam\steamapps\common\Minecraft\FTB_Launcher.exe"
You're done! Running FTB off your steam launcher should allow the steam overlay to kick in!
The process for adding Minecraft or any other modpack launcher (tekkit, void's wrath, etc) is very similar. Just replacing the steps with FTB with your desired launcher.
Here's a video that explains things pretty well too if you need it. (Thanks to DrRedAxel)