Linux RGB LED effect support for the Roccat Vulcan 100/120 Keyboard

This little binary adds some bling to your Roccat Vulcan 100/120 Keyboard when you use it in Linux. It supports setting up the default "Wave" effect that the keyboard can play on its own, as well as a more advanced homegrown "Impact" effect that responds to your keystrokes, and does some "ghost" typing when you're idle.

Installation

Ubuntu via Launchpad PPA

sudo add-apt-repository ppa:duncanthrax/roccat-vulcan
sudo apt-get update
sudo apt install roccat-vulcan
sudo udevadm control --reload-rules && udevadm trigger
# You might have to replug your keyboard or reboot at this
# point, so udev can update the permissions on the device nodes.
roccat-vulcan

Manual build (Expert zone)

You need to install development packages for libevdev, libhidapi, and libudev:

# Ubuntu
sudo apt install libevdev libhidapi libudev

# Fedora
sudo dnf install libevdev libevdev-devel systemd-devel libgudev1-devel libgudev1 hidapi hidapi-devel

Type make && make install in /src.
Replug keyboard or reboot unless you want to run as root.
Run roccat-vulcan.

If it does not work ...

When not running as root, you need to be a member of the plugdev group (check with id), and udev must have set up the device nodes accordingly.
Check the vendor/device ID of your keyboard with lsusb. The entry should look like this:
```
Bus 001 Device 035: ID 1e7d:307a ROCCAT
```
If your IDs aren't 1e7d:307a or 1e7d:3098, add an issue about it.

Changing effect colors

Effects use up to 10 colors which can be changed by specifying the -c command line option. Colors are specified as RGB values (decimal integer numbers), with an effective range of 0 (off) to 255 (full brightness for this color). However, since effects use color transformations on a time axis, it can make sense to specify values larger than 255 or smaller than zero. For example, if you want an effect color to be "redder" for longer, set the R value to 2500 instead of 255. Likewise, if you want to remove "greenishness" for longer, set the G value to a negative number.

These are the default colors of the "impact" effect:

colorIdx    R      G      B  Desc
------------------------------------------------
0           0      0    119  Base keyboard color (dark blue)
1        2303      0   -255  Typing color, initial key (over-red, under-blue)
2        2303      0   -143  Typing color, first neighbor key
3        2303      0      0  Typing color, second neighbor key
4         187      0    204  Ghost typing color, initial key
5         153      0    187  Ghost typing color, first neighbor key
6          85      0    170  Ghost typing color, second neighbor key

For example: To change the base keyboard color to green, specify -c 0:0,120,0.

Running as a background process (daemon)

Use start-stop-daemon, like this:

start-stop-daemon -S -b -x /usr/bin/roccat-vulcan -- [options]

This will prevent from running the binary twice. You can put this in /etc/rc.local or other equivalent locations.