GodotUO

Classic Ultima Online on Godot 4 .NET

Project maintained by DatMoshu Hosted on GitHub Pages — Theme by mattgraham

Canvas Background

What fills the window behind the game when the world view does not cover it (a phone in landscape with the world letterboxed, a desktop window larger than the game area). Source of truth: ADR-0016 (Accepted) and tools\bg_videos\README.md.

Upstream paints flat grey there. GUO draws a CanvasLayer at layer -1 (src\Render\CanvasBackground.cs) under everything, cover-scaled to the window. In the default mode the node is inactive and nothing changes.

Modes

Mode	Draws
`builtin-grey`	Upstream’s flat grey. The default; the node does nothing.
`builtin-wood`	A wood tile GUO owns, generated at first use (256x256, procedural).
`image`	A picture of yours, from `CanvasBackgroundPath`.
`video`	A looping, muted `.ogv` (Ogg Theora) of yours.
`frames`	A folder of numbered PNGs, or one sprite-sheet strip of square frames, played at `CanvasBackgroundFps` (default 12).
`builtin:<name>`	One of the ten shipped loops below.

A path that does not exist falls back to builtin-grey. The background is sampled Nearest for the wood tile (it is pixel art) and Linear for a player’s picture, video or frames; nothing else in the client changes its filter.

The ten built-in loops

Original procedural art, CC0, rendered by python tools\bg_videos\run.py into godot\GUO\assets\backgrounds\ as <name>.ogv (1280x720, 24 fps, Theora, no audio) plus <name>.png, the exact first frame used as the low-power still. backgrounds.json there is the manifest the client reads. Every theme is a pure function of the loop phase, so the last frame equals the first and the loop has no seam.

moongate-shimmer, candle-parchment, starlit-sea, drifting-fog, ember-drift, rain-on-stone, aurora-night, snowfall-pines, sunken-caustics, twin-moons.

To re-render one, run.py --only ember-drift; to render masters at another size, run.py --size 1920x1080 --out <folder outside the repo>. A contact sheet and a seam report land in build\bg_videos\.

Choosing one

In the game, Options, Video, the Background section: pick a mode, browse for a file, set the frame rate for frames, tick low power. Background packs installed from the Asset Store show up in the same list (Asset Store). The choice is saved in the character’s profile:

CanvasBackgroundMode   "builtin-grey"
CanvasBackgroundPath   ""
CanvasBackgroundFps    12
CanvasBackgroundLowPower  false

For a scripted run, --background <mode>[:<path>][@fps][,lowpower] overrides the profile and is never saved, for example --background builtin:starlit-sea or --background frames:D:\loops\rain@8,lowpower.

Adding your own

A picture: any image Godot loads; mode image.
A video: encode to Ogg Theora (.ogv), the one video format Godot plays without a plugin; mode video. It loops and is muted.
Frames: a folder of PNGs in natural order (frame_2 before frame_10), or one PNG whose name ends in a strip suffix and holds square frames side by side; mode frames. On a phone a picked file is copied into the user directory, because a content URI cannot be reopened later; a folder cannot be, so on a phone frames means a sheet.
A new built-in: add a theme to tools\bg_videos, render it, and it appears in backgrounds.json; the client lists whatever the manifest lists.

Low power

With CanvasBackgroundLowPower on, a video pauses once its first frame has decoded and frames never advances: the background becomes a still. Mobile and Web profiles get it on through the per-platform table at profile version 6 (see Mobile UI); the desktop leaves it off.

What was verified

ADR-0016’s validation section covers the mode switch, the profile round trip, the fallback on a missing path and the migration to version 6. The loops’ seamlessness is the tool’s seam report, checked when they were rendered.