vkSumi

A Vulkan layer for runtime color grading on Linux. Brightness, contrast, saturation, hue, gamma, temperature, tint, RGB gain, 3-band lift/gain. Live .conf file with hot reload. Per-game configs. The Adrenalin / NVIDIA Freestyle equivalent the platform's been missing.

Made because vkBasalt is unmaintained and the only other option is ReShade -> wine -> inject -> pray (waste of time for some minor tweaks, ain't installing all that.).

Little note that this does NOT replace VkBasalt's other functionalities (such as CAS, Denoise, etc.), this is purely for color grading sliders.

Screenshots

Before	After

Installation / Build

AUR

yay -S vksumi

Flatpak

You can install it manually for now. Grab one or both .flatpak files in the releases page and then run in your terminal:

flatpak install vkSumi-24.08.flatpak 
# or
flatpak install vkSumi-25.08.flatpak 

Manual building

meson setup builddir --prefix="$HOME/.local"
ninja -C builddir
meson install -C builddir

Drops the .so in ~/.local/lib/, the layer manifest in ~/.local/share/vulkan/implicit_layer.d/, and the toggle script in ~/.local/bin/.

Use

The layer only activates when ENABLE_VKSUMI=1 is set, otherwise it's invisible.

Native Linux:

env ENABLE_VKSUMI=1 some-vulkan-game

Steam (any game) - right-click -> Properties -> Launch Options:

ENABLE_VKSUMI=1 %command%

Works for Proton/DXVK too since DXVK speaks Vulkan underneath.

Kill switch if a game breaks: DISABLE_VKSUMI=1 ... (always wins over enable).

Config

Lives at ~/.config/vkSumi/vkSumi.conf (global) and ~/.config/vkSumi/games/<exe-name>.conf (per-game, auto-created on first launch). Per-game files merge on top of global, only set what you want different.

enabled     = true
toggle_keys = Shift_R+F9

brightness  = 0.0    # [-1 .. 1]
contrast    = 0.0    # [-1 .. 1]
exposure    = 0.0    # EV stops
saturation  = 0.0    # -1 = grayscale
hue_deg     = 0.0    # [-180 .. 180]
gamma       = 0.0    # + brightens midtones
temperature = 0.0    # warm (+) cool (-)
tint        = 0.0    # magenta (+) green (-)

red_gain    = 0.0
green_gain  = 0.0
blue_gain   = 0.0

shadows     = 0.0    # to increase shadows depth go negative (-)
midtones    = 0.0
highlights  = 0.0

PER_GAME_CONFIG_CREATION=true     # per-game .conf file creation (true by default)
VKSUMI_CONFIG_FILE=path/to/.conf  # path to another .conf file that act as a global substitute

See vkSumi.conf.example for the full annotated version.

Hotkey

Two ways:

In-layer (X11 + XWayland, so Wine/Proton games work): Set toggle_keys = Shift_R+F9 in the conf. Press the combo while the game window is focused. Format is "+"-separated X11 keysym names (full list in /usr/include/X11/keysymdef.h).

Script + compositor bind:

# Hyprland (~/.config/hypr/hyprland.conf)
bind = SHIFT, F9, exec, vksumi-toggle

# sway (~/.config/sway/config)
bindsym Shift+F9 exec vksumi-toggle

The script flips enabled in the conf, inotify catches it, instant reload.

Known limits

• HDR: detected and passed through unchanged. Doing color grading correctly on PQ / scRGB needs a different shader path, not done yet.
• Native Wayland Vulkan games: in-layer hotkey doesn't work (Wayland blocks key grabs from clients). Use the toggle script instead.

Debugging

ENABLE_VKSUMI=1 VKSUMI_DEBUG=1 some-game

Dumps every layer call to stderr. Useful when something looks weird.

Credits

Architecture lifted from vkBasalt (RIP). MangoHud's code helped figure out a few tricky bits.

License

MIT.