Alex Jurkiewicz b0572ae83a perf(map-generator): major CPU and memory optimisations (#3860)
## Description:

Five performance improvements to the map generator, measured on three
maps of increasing size. End-to-end time on `world` improved ~15×, heap
allocations ~19×.

| Map | Before | After | Speedup |
|-----|--------|-------|---------|
| bosphorusstraits (~612K tiles) | 578ms / 594MB | 45ms / 134MB | 13× /
4.4× |
| world (~2M tiles) | 2333ms / 2128MB | 150ms / 553MB | 15× / 3.8× |
| giantworldmap (~8M tiles) | 10701ms / 9300MB | 635ms / 2509MB | 17× /
3.7× |

Changes (one commit each):
- **`--workers` flag**: bounds concurrent map processing to limit peak
memory
- **Flat `[]bool` visited sets**: replaced `map[string]bool` keyed by
`fmt.Sprintf` with flat `[]bool` indexed `x*height+y` — the dominant
cost
- **`neighborCoords` with stack buffer**: eliminates per-call slice
allocation for neighbour lookups
- **`Terrain` struct 24→16 bytes**: field reorder + `uint8` type for
`TerrainType`
- **Nil buffers early**: releases image/terrain arrays as soon as
they're no longer needed
- **BFS mark-visited on push**: each tile enters the queue once instead
of up to 4×, halving queue memory


also fixes a bug (according to Claude):

Here's the bug: createMiniMap downscales by averaging/sampling 2x2
blocks, copying field values across — including Ocean=true from the
parent scale. When a single connected ocean at 1x splits into multiple
disconnected bodies at 4x (because narrow water channels disappear when
you halve resolution), those smaller fragments still carry Ocean=true
from the carryover. The 4x processWater call picks the new largest
fragment and sets it to Ocean=true, but never clears the others — so
multiple disconnected bodies end up flagged as Ocean.

This PR's fix: before the new BFS pass, zero out every Ocean flag, so
only the truly-largest body at the current scale ends up marked.

It's incidental to the perf work but it's a real semantic change — the
on-disk .bin files will differ from main on any map where ocean splits
across downscaling. The PR doesn't mention it, which is why I flagged
it.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-05-06 14:38:49 -06:00
2025-06-22 08:14:08 -07:00
2026-05-06 12:48:35 -06:00
2026-05-06 13:09:58 -06:00
2025-05-15 23:09:39 -04:00
2026-04-29 12:49:19 -06:00
2025-03-06 15:50:29 -08:00
2025-05-15 23:09:39 -04:00
2026-03-23 13:40:21 -07:00
2026-04-29 12:49:19 -06:00
2026-01-21 10:00:55 -08:00
2026-05-04 12:53:02 -06:00
2026-01-08 13:34:18 -08:00
2026-04-30 21:27:35 -06:00
2026-04-01 20:03:39 -07:00

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.

🎮 Running the Game

Development Mode

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

npm run dev

This will:

  • Start the webpack dev server for the client
  • Launch the game server with development settings
  • Open the game in your default browser (to disable this behavior, set SKIP_BROWSER_OPEN=true in your environment)

Client Only

To run just the client with hot reloading:

npm run start:client

Server Only

To run just the server with development settings:

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
    
  • Testing

    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')
  5. Push to the branch (git push origin amazing-feature)
  6. Open a Pull Request

🌐 Translation

Translators are welcome! Please feel free to help translate into your language. How to help?

  1. Join the translation Discord
  2. Go to the project's Crowdin translation page: https://crowdin.com/project/openfront-mls
  3. Login if you already have an account / Sign up if you don't have one
  4. Join the project
  5. Select the language you want to translate in. If your language isn't on the list, click the "Request New Language" button and enter the language you want added there.
  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

  3. Core Contributors: Only those with extensive experience with the project may modify critical game systems

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
    • Describe what testing you've performed
    • Be responsive to feedback and requested changes
  4. Testing Requirements:

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

Communication

  • Be respectful and constructive in all project interactions
  • Questions are welcome, but please search existing issues first
  • 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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