Target a couple of hot paths: - In Actor, cache the renderables enumerable by tracking the last used WorldRenderer. It's slightly uncouth but in practise the WorldRenderer will be the same for the lifetime of the Actor and outlive it anyway. - In RenderSprites, cache the renderables enumerable. If we refresh the palettes directly, we don't need the WorldRenderer for anything else so can return a cached enumerable. This could result in iterating the animation list twice, so use a flag to only do it when required, which is rare. - In AutoTarget, the compiler has an unfortunate behaviour where it allocates the helper class for a capturing lambda at the top of the loop, but it's on a rare path and so this allocation is usually unused. We can discourage the compiler from allocating until it's actually needed by wrapping the call in a local function.
OpenRA
A Libre/Free Real Time Strategy game engine supporting early Westwood classics.
- Website: https://www.openra.net
- Chat: #openra on Libera (web) or Discord

- Repository: https://github.com/OpenRA/OpenRA
Please read the FAQ in our Wiki and report problems at https://github.com/OpenRA/OpenRA/issues.
Join the Forum for discussion.
Play
Distributed mods include a reimagining of
- Command & Conquer: Red Alert
- Command & Conquer: Tiberian Dawn
- Dune 2000
EA has not endorsed and does not support this product.
Check our Playing the Game Guide to win multiplayer matches.
Contribute
- Please read INSTALL.md and Compiling on how to set up an OpenRA development environment.
- See Hacking for a (now very outdated) overview of the engine.
- Read and follow our Code of Conduct.
- To get your patches merged, please adhere to the Contributing guidelines.
Mapping
- We offer a Mapping Tutorial as you can change gameplay drastically with custom rules.
- For scripted mission have a look at the Lua API.
- If you want to share your maps with the community, upload them at the OpenRA Resource Center.
Modding
- Download a copy of the OpenRA Mod SDK to start your own mod.
- Check the Modding Guide to create your own classic RTS.
- There exists an auto-generated Trait documentation to get started with yaml files.
- Some hints on how to create new OpenRA compatible Pixelart.
- Upload total conversions at our Mod DB profile.
Support
- Sponsor a mirror server if you have some bandwidth to spare.
- You can immediately set up a Dedicated Game Server.
License
Copyright (c) OpenRA Developers and Contributors This file is part of OpenRA, which is free software. It is made available to you under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. For more information, see COPYING.
Sponsors
Free code signing on Windows provided by SignPath.io, certificate by SignPath Foundation.