Arkadiusz Sygulski 6bd95d4884 Pathfinding - optimize naval invasions (#2932)
# Pathfinding pt. 4

https://pf-pt-4.openfront.dev/

## Description:

Hello again! Pathfinding. It's fast, but inaccurate. This PR makes it
more accurate and actually faster. Sadly it is _faster_ because of a
blunder in previous PR (using BucketQueue where MinHeap would be
better), not because of a new tech. More importantly, it is more
accurate. And that's what people apparently want.

## What changed?

Most of the functional changes relate to `SpatialQuery` module. This is
the thingy that answers "we know the target, which tile of my territory
is the best to launch an invasion". To make it compute a path from South
America to the deep inland China river, it has to work on a coerced map,
one with a very small resolution, so small in fact, that every 4096 map
tiles gets compressed to just one pixel. I hope you see where this is
going.

Previously we selected a random coastal tile within this big pixel
(honestly it wasn't random at all, but could very well be for the
illustrative purposes). Now, we try to be a bit more deliberate. Since
we already know the rough location of the probably best tile, we can
exclude all other tiles from the computation. Imagine a player's
territory spans both Americas on global map - that's a lot of shores.
But since we already know the best tile is somewhere close to Miami, the
problem space was greatly reduced, no need to consider all other shores.
But pathing to the target in China from Miami is still crazy expensive.

This is where second trick comes to play - instead of pathing all the
way to China, we select a _waypoint_ in the rough direction of China,
about 100 to 200 tiles away. This way we fairly cheaply select best tile
to launch an invasion towards this abstract point. And chances are, this
point is far enough, the newly computed path is very close to being
optimal. When you throw a dart from far away, the difference between
scoring 10 and missing is very small. This is why aiming in the general
direction of the board - as opposed to the ceiling - is usually good
enough.

## Okay, but what about the crazy paths when I send invasion to the
opposed bank of a river?!

Well, pathing from America to China is cool, but most players wouldn't
notice the difference on such long paths, what about the short ones? We
now try more accurate pathing first and defer to hierarchy only if it
fails. This produces much better paths for short invasions. While the
fix described above ensures the accuracy is improved also on
medium-to-long routes.

## Playground

Yes.


https://github.com/user-attachments/assets/9cf9586f-c99a-416d-b856-8cf0a21c35ed

## CodeRabbit

Grab a 🥕. Remember `tests/pathfinding/playground` is mostly generated
code and go easy on it. It's enough for it to work and do it's job of
visualizing the paths. No need for throughout review of these files.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

moleole
2026-01-16 23:10:55 +00:00
2025-06-22 08:14:08 -07:00
2025-09-30 11:13:32 -07:00
2026-01-16 10:20:47 -08:00
2025-05-15 23:09:39 -04:00
2025-03-06 15:50:29 -08:00
2025-05-15 23:09:39 -04:00
2025-07-22 21:11:28 -04:00
2026-01-08 13:34:18 -08:00

OpenFrontIO Logo

OpenFront.io is an online real-time strategy game focused on territorial control and alliance building. Players compete to expand their territory, build structures, and form strategic alliances in various maps based on real-world geography.

This is a fork/rewrite of WarFront.io. Credit to https://github.com/WarFrontIO.

CI Crowdin CLA assistant License: AGPL v3 Assets: CC BY-SA 4.0

License

OpenFront source code is licensed under the GNU Affero General Public License v3.0

Current copyright notices appear in:

  • Footer: "© OpenFront and Contributors"
  • Loading screen: "© OpenFront and Contributors"

Modified versions must preserve these notices in reasonably visible locations.

See the LICENSE for complete requirements.

For asset licensing, see LICENSE-ASSETS.
For license history, see LICENSING.md.

🌟 Features

  • Real-time Strategy Gameplay: Expand your territory and engage in strategic battles
  • Alliance System: Form alliances with other players for mutual defense
  • Multiple Maps: Play across various geographical regions including Europe, Asia, Africa, and more
  • Resource Management: Balance your expansion with defensive capabilities
  • Cross-platform: Play in any modern web browser

📋 Prerequisites

  • npm (v10.9.2 or higher)
  • A modern web browser (Chrome, Firefox, Edge, etc.)

🚀 Installation

  1. Clone the repository

    git clone https://github.com/openfrontio/OpenFrontIO.git
    cd OpenFrontIO
    
  2. Install dependencies

    npm run inst
    

    Do NOT use npm install nor npm i but instead use our npm run inst. It runs the safer npm ci --ignore-scripts to install dependencies exactly according to the versions in package-lock.json and doesn't run scripts. This can prevent being hit by a supply chain attack.

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Development Mode

Run both the client and server in development mode with live reloading:

npm run dev

This will:

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To run just the client with hot reloading:

npm run start:client

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npm run start:server-dev

Connecting to staging or production backends

Sometimes it's useful to connect to production servers when replaying a game, testing user profiles, purchases, or login flow.

To replay a production game, make sure you're on the same commit that the game you want to replay was executed on, you can find the gitCommit value via https://api.openfront.io/game/[gameId]. Unfinished games cannot be replayed on localhost.

To connect to staging api servers:

npm run dev:staging

To connect to production api servers:

npm run dev:prod

🛠️ Development Tools

  • Format code:

    npm run format
    
  • Lint code:

    npm run lint
    
  • Lint and fix code:

    npm run lint:fix
    
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    npm test
    

🏗️ Project Structure

  • /src/client - Frontend game client
  • /src/core - Shared game logic
  • /src/server - Backend game server
  • /resources - Static assets (images, maps, etc.)

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

  1. Request to join the development Discord.
  2. Fork the repository
  3. Create your feature branch (git checkout -b amazing-feature)
  4. Commit your changes (git commit -m 'Add some amazing feature')
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Translators are welcome! Please feel free to help translate into your language. How to help?

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  4. Join the project
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  6. Translate the strings

Feel free to ask questions in the translation Discord server!

Project Governance

  • The project maintainer (evan) has final authority on all code changes and design decisions
  • All pull requests require maintainer approval before merging
  • The maintainer reserves the right to reject contributions that don't align with the project's vision or quality standards

Contribution Path for New Contributors

To ensure code quality and project stability, we use a progressive contribution system:

  1. New Contributors: Limited to UI improvements and small bug fixes only

    • This helps you become familiar with the codebase
    • UI changes are easier to review and less likely to break core functionality
    • Small, focused PRs have a higher chance of being accepted
  2. Established Contributors: After several successful PRs and demonstrating understanding of the codebase, you may work on more complex features

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How to Contribute Successfully

  1. Before Starting Work:

    • Open an issue describing what you want to contribute
    • Wait for maintainer feedback before investing significant time
    • Small improvements can proceed directly to PR stage
  2. Code Quality Requirements:

    • All code must be well-commented and follow existing style patterns
    • New features should not break existing functionality
    • Code should be thoroughly tested before submission
    • All code changes in src/core MUST be tested.
  3. Pull Request Process:

    • Keep PRs focused on a single feature or bug fix
    • Include screenshots for UI changes
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  4. Testing Requirements:

    • Verify your changes work as expected
    • Test on multiple systems/browsers if applicable
    • Document your testing process in the PR

Communication

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  • For major changes, discuss in an issue before starting work

Final Notes

Remember that maintaining this project requires significant effort. The maintainer appreciates your contributions but must prioritize long-term project health and stability. Not all contributions will be accepted, and that's okay.

Thank you for helping make OpenFront better!

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