Game streaming

Sunshine streams a desktop to Moonlight clients. Pointed at a virtual output, it streams a monitor that exists only for the session, at the client’s resolution and frame rate, while the physical monitors keep their layout.

This setup needs Sunshine and jq.

Session script

Sunshine runs a command before a stream starts and another after it ends. Save this as ~/.config/sunshine/umbriel-output.sh and make it executable:

#!/bin/sh
set -eu

name=sunshine

case "$1" in
    create)
        umbriel output-destroy "$name" >/dev/null 2>&1 || true
        umbriel output-create "$name" \
            "${SUNSHINE_CLIENT_WIDTH:-1920}x${SUNSHINE_CLIENT_HEIGHT:-1080}@${SUNSHINE_CLIENT_FPS:-60}" >/dev/null
        ;;
    remove)
        # Give windows that the app's undo command is closing up to 5 seconds to
        # go away, so they do not flash onto a physical monitor.
        i=0
        while [ "$i" -lt 25 ]; do
            left="$(umbriel windows --json |
                jq --arg out "$name:" '[.[] | select(.workspace | startswith($out))] | length')"
            [ "$left" = 0 ] && break
            sleep 0.2
            i=$((i + 1))
        done
        # Move what is left to the focused workspace of another output, so it
        # does not return to the next session's output (see below).
        target="$(umbriel workspaces --json |
            jq -r --arg out "$name" '[.[] | select(.output != $out and .active)]
                | (map(select(.focused)) + .) | first | "\(.name)/\(.output)" // empty')"
        for id in $(umbriel windows --json |
            jq -r --arg out "$name:" '.[] | select(.workspace | startswith($out)) | .id'); do
            [ -n "$target" ] || break
            umbriel msg "window-focus:$id"
            umbriel msg "window-move-to-workspace-silent:$target"
        done
        umbriel output-destroy "$name" >/dev/null 2>&1 || true
        ;;
esac

Destroying an output moves its windows to another output, as when a monitor is unplugged, and Umbriel remembers the output as their home: when an output with the same name appears again, they move back to it. That is right for a monitor that returns after suspend, but it would pull a terminal that once opened on the stream onto every later stream. An explicit move, like the one above, drops that memory.

Sunshine configuration

In ~/.config/sunshine/sunshine.conf, capture through wlr-screencopy, select the output by name, and run the script around every session:

capture = wlr
output_name = sunshine
global_prep_cmd = [{"do":"/home/user/.config/sunshine/umbriel-output.sh create","undo":"/home/user/.config/sunshine/umbriel-output.sh remove"}]

Replace /home/user with your home directory. Restart Sunshine after editing sunshine.conf or apps.json; it reads both only at startup.

Opening applications on the stream

New windows open on the output under the pointer, which is usually a physical monitor. Use a window rule to send an application to the stream instead. For Steam Big Picture:

[[window_rule]]
match.app_id = "^steam$"
match.title = "[Bb]ig [Pp]icture"
default_output = "sunshine"
default_fullscreen = true

When the output does not exist, default_output is ignored and the window opens as usual. Rules also apply when a title arrives after the window maps, so Big Picture lands on the stream even when Steam switches an existing window into it. default_fullscreen covers the case where Steam, already running, opens Big Picture without asking for fullscreen.

In Sunshine’s apps.json, launch Big Picture and close it when the session ends. Sunshine runs an app’s undo command before the global one, so the script waits for Big Picture to close before it destroys the output:

{
    "name": "Steam Big Picture",
    "detached": ["steam steam://open/bigpicture"],
    "prep-cmd": [{"do": "", "undo": "steam steam://close/bigpicture"}],
    "image-path": "steam.png"
}

Closing Big Picture makes Steam map its main window again. A new window takes focus by default, and Steam’s may switch a physical monitor to its workspace. To keep focus where it was, give that window default_focused = false only for the length of a session: include a file that the script fills in create and empties in remove, then reload with umbriel msg config-reload.

Games

Games launched from Big Picture need a rule of their own. Proton games report an application ID of steam_app_<id>:

[[window_rule]]
match.app_id = "^steam_app_"
default_output = "sunshine"

Proton through Wine’s Wayland driver (PROTON_USE_WAYLAND=1) picks its primary monitor by itself and sizes fullscreen games for it. When that is a physical monitor, the game renders at that monitor’s size and the stream shows only the top-left part of it. Name the stream’s output instead, in the game’s launch options:

WAYLANDDRV_PRIMARY_MONITOR=sunshine %command%