Don't you wish that your homebrew Godot game could deliver updates to your players? During our development cycle we found that we regularly had updates representing only a few MB of changes, but our total PCK file was ~700MB. We want our users to be able to download only the bytes which have changed!
This project takes an outdated PCK file and a small binary diff as inputs. It creates the updated PCK file necessary to run the newest version of a game. It can then load the updated PCK.
The patch system works for any stream of updates. It only works for Mac, Windows and Linux/X11.
We plan to write a simple script to help publish new releases (issue #5). There is a public webserver which can be queried for metadata about new versions ("deltas" containing the URL of the binary diff as well as checksums for the diff and the expected PCK output).
See the official docs for more information on Godot Engine's support for live-reloading of PCK (game payload) files.
First of all, this is a demo. Until we have more time to test it out with a few small game deployments, we can't offer much in the way of support. That said, the strategy seems promising as a stopgap until Godot engine provides an official alternative.
You must:
- manage the version of your Godot game carefully
- host delta server, which describes version diffs
- host the diffs on something like S3, a CDN, or your own webserver
To make this system work, your Godot app needs to have access to a resource at res://release.tres as defined in release.gd:
extends Resource
export var version: StringThis will be used to query for new versions of your game from the delta (patch metadata) server. You must use Semantic Versioning formatting, or the delta server will reject your queries.
Make sure to update this resource every time you release a new version of your software, as it will be used to query for updates.
delta-server responds to queries for metadata about what, if any, package updates are available for an app. It provides an admin route so that the owner can register metadata about new releases. You must maintain this server in a publicly-available space so that users can keep their app up to date.
The diffs referenced by delta-server need to be hosted in something like cloud storage, a CDN, or your favorite webserver.
The creation of the exported payloads becomes more complex than a normal godot app, using this system. We want to create rust binaries for use in Mac, Windows, and Linux/X11 environments.
We have github actions configured so that each tagged release pushes shared libs for all three platforms to the releases page.
The payload exported by Godot will must contain a library file specific to your client's gaming environment. For example, if you export as a Linux/X11 app, your deliverable has a .so library in addition to the pck and the executable:
libincremental_patch.so linux-test.pck linux-test.x86_64
Still in the planning stage: the shared lib appropriate for a given client OS must be fetched from the github releases page if it doesn't already exist on the machine performing the export step.