2 Commits

Author	SHA1	Message	Date
Arkadiusz Sygulski	0e3ced3bfa	Pathfinding Refactor pt. 2 (#2866) ... ## Playtest https://pf-pt-2.openfront.dev/ ## Pathfinding Refactor pt. 2 <img width="1536" height="1024" alt="image" src="https://github.com/user-attachments/assets/9477958e-54b7-4c83-b317-ba789e809e9e" /> This is a follow-up to a previous PR introducing pathfinding changes. This time, it introduces a complete refactor of `pathfinding` directory and breakdown into composable pieces. ### Unified PathFinder interface `PathFinder<T>` and `SteppingPathFinder<T>` are introduced to unify **all** pathfinding across the application. First one exposes complete path, while stepping variant allows the callee to iterate over the path by calling `.next`. All pathfinders share this one common interface, which makes them easy to use in any scenario - `PathFinding.Water(game).search(from, to)`. `SteppingPathFinder<T>` extends `PathFinder<T>` with an ability to iterate over the path. It handles caching, storing current index and invalidation. This allows the units to not care about the inner workings of the pathfinder and just call `pf.next(current, target)` and receive instructions on what to do next. ### Common entry point All pathfinders are now exposed from common `PathFinding` entrypoint: - `PathFinding.Water` - `PathFinding.Rail` - `PathFinding.Stations` - `PathFinding.Rail` Additional entry point is introduced for pathfinders which need to work both in the worker, but also on the frontend, which lacks `Game` interface. Currently only `UniversalPathFinding.Parabola` is available. ### Spatial Query New module has been introduced close to `pathfinding` - `SpatialQuery`. It aims to resolve any questions game may have about finding tiles meeting criteria. Currently `SpatialQuery.closestShore(player, target)` and `SpatialQuery.closestShoreByWater(player, target)` are available - they help answering questions about naval invasion: "What is the best landing location from user's click?" and "Which our tile should be used to launch the transport ship?". Under the hood they use very similar mechanics to pathfinding, so it felt right to put them close by. ### Modular architecture Pathfinders now support transformers: `MiniMapTransformer`, `ShoreCoercingTransformer`, `ComponentCheckTransformer`, `SmoothingTransformer`. Transformers functions like a middleware in the pathfinding chain. They wrap around the pathfinder and provide additional functionality. This allows the pathfinder to focus on actually finding the path instead of doing unrelated things. Example chain for simple (A*) water pathfinding: ```ts static WaterSimple(game: Game): SteppingPathFinder<TileRef> { const miniMap = game.miniMap(); const pf = new AStarWater(miniMap); return PathFinderBuilder.create(pf) .wrap((pf) => new ShoreCoercingTransformer(pf, miniMap)) .wrap((pf) => new MiniMapTransformer(pf, game.map(), miniMap)) .buildWithStepper(tileStepperConfig(game)); } ``` The Pathfinder - here `AStarWater` - does not care about the conversion between minimap and main map tiles. It also does not care if the source or destination is a land tile. The transformers take care of that. The pathfinder gets a set of valid coordinates and produces the path - that's it. Modular approach makes working on a particular set of utilities much easier - for example map upscaling is handled consistently across all pathfinders. Additionally, the pathfinders are not tied to the particular map resolution used. Pass them a different map and they will work the same. ### Algorithms Algorithms used are neatly organized inside `src/core/pathfinding/algorithms`. They are prefixed with the algorithm name and suffixed with the use case. File without suffix exposes generic version ready to traverse any graph with adapters. Specialized versions either use an adapter or inline logic when performance is critical - using adapters leads to 20-30% performance loss. The directory includes `A*` and `BFS` but also other useful utils, such as `AbstractGraph` used to generate... an abstract graph on top of the tile map and `ConnectedComponents` helping to identify whether two tiles are connected by a path without actually computing the path. ### Playground The playground have been updated with new algorithms, including tweaked very greedy `A*`. <img width="2175" height="1424" alt="image" src="https://github.com/user-attachments/assets/1f833651-0024-4299-bf86-882f5368358c" /> ### Tests Yeah, there are some, a little too many if I say so myself. But there are no useless tests. I had to ensure refactored code works somehow reliably. This PR comes with trust me bro guarantee, but I would appreciate someone confirming **naval invasions, nukes (esp. MIRV) and warships**. ### Discord `moleole` GL & HF	2026-01-11 20:11:14 -08:00
Arkadiusz Sygulski	b090f2f624	HPA* Pathfinding (#2815) ... ## Pathfinding with HPA* Hi! The primary objective of this PR is to replace per-tile A* with hierarchical pathfinding - HPA*. In practice, this means we create an abstract graph on top of the actual map with far fewer points and use it to decide on general path structure. Only then we go back to tile-level and build path between selected waypoints. This speeds up long distance pathfinding by over 1000x in some cases. To make the review easier, it comes with a benchmark and visual playground. ## PREPROCESSING H part of HPA* means "hierarchical" and requires preprocessing. This PR includes pre-processing as part inside `new Game()` constructor. It takes about 135ms for `giantworldmap` on my machine, which increases the effective initialization from ~95ms to ~230ms. This time could be reduced in different ways, which are **out of scope** for this PR. After confirming the initialization time is bearable on low-end devices, I argue merging this PR as-is is acceptable tradeoff. It creates small lag at the beginning of a round but pays for itself in the first minute of the match. ## Nerdy details **Architecture** - HPA*-style hierarchical pathfinding - 32×32 sectors on minimap with gateway nodes on borders - Gateway graph built via BFS during preprocessing - Water component optimization skips unreachable gateway pairs - A* on gateway graph → local A* within sectors → Bresenham path smoothing - Minimap upscaling identical to currently used in MiniAStar **Key Optimizations** - Typed arrays instead of high-level primitives - Stamp-based visited tracking (no need to recreate buffers, O(1) clearing) - Optional - enabled by default - caching of tile paths between gateways - Line of sight smoothing for the final path ## Review Focus Play with included tools, benchmark and visualization. Pathfinding should be safe to merge as a black box - you do not need to understand the details. Outcomes can be tested empirically in-game. Visualize (and share!) edge cases with included playground. Confirm the 100x speedup is real with benchmark. If you plan to dive into the code, I suggest the following order: - Pathfinding abstraction in `src/core/pathfinding/` - Pathfinding tests in `tests/core/pathfinding/` - NavMesh in `src/core/pathfinding/navmesh/` + integration with `Game.ts` - Benchmark in `tests/pathfinding/benchmark/` Do not look at playground's code, it has been created with a clanker. The design is 100% mine and I spent way too long polishing it, but I haven't even once edited the code manually. There is probably no abstraction whatsoever, just do not look at the code, let it play. ## Core Changes #### Pathfinding (`src/core/pathfinding/navmesh/`) - HPA* + refinement -> three phased pathfinding: A* over the graph -> naive path -> refinement - comes with A* and BFS optimized for for specific needs #### Pre-Processing (`src/core/pathfinding/navmesh/`) - identify water bodies to avoid pathfinding between disconnected nodes - create high-level graph of gateways on top of tile map #### Abstraction (`src/core/pathfinding/`) - common `PathFinder` interface that can return full path and also act as state machine (`.next()`) - adapters for both new and legacy algorithm with fallback to legacy if navigation mesh not available #### Benchmark (`tests/pathfinding/benchmark/`) - `npx tsx tests/pathfinding/benchmark/run.ts` - no guesswork, numbers - `npx tsx tests/pathfinding/benchmark/run.ts --synthetic` - 1000s of synthetic paths - `npx tsc tests/pathfinding/benchmark/generate.ts` - generate more as needed, test new maps - includes ONE synthetic scenario to avoid PR bloat, generate more locally / later #### Playground (`tests/pathfinding/playground/`) - `npx tsx tests/pathfinding/playground/server.ts` - visualize paths with both new and legacy algorithm ## Benchmarks ### Compared with legacy in default - hand picked - scenario: ``` Initialization: 95.95ms -> 227.29ms Pathfinding: 3038.43ms -> 6.45ms Distance: 26972 -> 26810 tiles ``` ### 42,000 synthetic routes across all maps ``` Running 42 synthetic scenarios with hpa.cached adapter... ✅ synthetic/achiran | Init: 93.42ms | Path: 139.07ms | Dist: 1481630 tiles | Routes: 1000/1000 ✅ synthetic/africa | Init: 87.14ms | Path: 155.08ms | Dist: 1829414 tiles | Routes: 1000/1000 ✅ synthetic/asia | Init: 57.60ms | Path: 112.55ms | Dist: 1204082 tiles | Routes: 1000/1000 ✅ synthetic/australia | Init: 78.18ms | Path: 77.12ms | Dist: 978375 tiles | Routes: 1000/1000 ✅ synthetic/baikal | Init: 78.26ms | Path: 152.14ms | Dist: 1600016 tiles | Routes: 1000/1000 ✅ synthetic/baikalnukewars | Init: 81.44ms | Path: 165.90ms | Dist: 1699283 tiles | Routes: 1000/1000 ✅ synthetic/betweentwoseas | Init: 29.29ms | Path: 114.99ms | Dist: 1338075 tiles | Routes: 1000/1000 ✅ synthetic/blacksea | Init: 30.66ms | Path: 93.14ms | Dist: 949217 tiles | Routes: 1000/1000 ✅ synthetic/britannia | Init: 74.12ms | Path: 85.62ms | Dist: 866752 tiles | Routes: 1000/1000 ✅ synthetic/deglaciatedantarctica | Init: 105.49ms | Path: 192.93ms | Dist: 1574684 tiles | Routes: 1000/1000 ✅ synthetic/didier | Init: 81.51ms | Path: 153.70ms | Dist: 1734876 tiles | Routes: 1000/1000 ✅ synthetic/eastasia | Init: 49.29ms | Path: 128.63ms | Dist: 1410270 tiles | Routes: 1000/1000 ✅ synthetic/europe | Init: 92.55ms | Path: 178.35ms | Dist: 1525216 tiles | Routes: 1000/1000 ✅ synthetic/europeclassic | Init: 33.50ms | Path: 104.40ms | Dist: 1209759 tiles | Routes: 1000/1000 ✅ synthetic/falklandislands | Init: 63.00ms | Path: 107.41ms | Dist: 1080251 tiles | Routes: 1000/1000 ✅ synthetic/faroeislands | Init: 71.91ms | Path: 49.52ms | Dist: 604613 tiles | Routes: 1000/1000 ✅ synthetic/fourislands | Init: 45.75ms | Path: 78.91ms | Dist: 937439 tiles | Routes: 1000/1000 ✅ synthetic/gatewaytotheatlantic | Init: 81.00ms | Path: 257.06ms | Dist: 2555551 tiles | Routes: 1000/1000 ✅ synthetic/giantworldmap | Init: 214.25ms | Path: 220.42ms | Dist: 1976693 tiles | Routes: 1000/1000 ✅ synthetic/gulfofstlawrence | Init: 45.16ms | Path: 96.05ms | Dist: 1014604 tiles | Routes: 1000/1000 ✅ synthetic/halkidiki | Init: 74.68ms | Path: 149.39ms | Dist: 1546781 tiles | Routes: 1000/1000 ✅ synthetic/iceland | Init: 58.72ms | Path: 78.16ms | Dist: 1001554 tiles | Routes: 1000/1000 ✅ synthetic/italia | Init: 29.78ms | Path: 139.93ms | Dist: 1412024 tiles | Routes: 1000/1000 ✅ synthetic/japan | Init: 161.07ms | Path: 118.65ms | Dist: 1154393 tiles | Routes: 1000/1000 ✅ synthetic/lemnos | Init: 52.59ms | Path: 136.69ms | Dist: 1481101 tiles | Routes: 1000/1000 ✅ synthetic/lisbon | Init: 49.27ms | Path: 86.53ms | Dist: 1032011 tiles | Routes: 1000/1000 ✅ synthetic/manicouagan | Init: 53.74ms | Path: 110.52ms | Dist: 1307630 tiles | Routes: 1000/1000 ✅ synthetic/mars | Init: 29.39ms | Path: 80.55ms | Dist: 1091702 tiles | Routes: 1000/1000 ✅ synthetic/mena | Init: 26.37ms | Path: 120.09ms | Dist: 1272751 tiles | Routes: 1000/1000 ✅ synthetic/montreal | Init: 26.08ms | Path: 106.77ms | Dist: 1187736 tiles | Routes: 1000/1000 ✅ synthetic/newyorkcity | Init: 56.60ms | Path: 181.19ms | Dist: 1753875 tiles | Routes: 1000/1000 ✅ synthetic/northamerica | Init: 96.29ms | Path: 123.02ms | Dist: 1217221 tiles | Routes: 1000/1000 ✅ synthetic/oceania | Init: 52.81ms | Path: 51.96ms | Dist: 482373 tiles | Routes: 1000/1000 ✅ synthetic/pangaea | Init: 21.29ms | Path: 56.58ms | Dist: 716189 tiles | Routes: 1000/1000 ✅ synthetic/pluto | Init: 53.89ms | Path: 141.62ms | Dist: 1304362 tiles | Routes: 1000/1000 ✅ synthetic/southamerica | Init: 85.19ms | Path: 123.03ms | Dist: 1301403 tiles | Routes: 1000/1000 ✅ synthetic/straitofgibraltar | Init: 76.68ms | Path: 108.30ms | Dist: 1304592 tiles | Routes: 1000/1000 ✅ synthetic/straitofhormuz | Init: 38.97ms | Path: 67.78ms | Dist: 754920 tiles | Routes: 1000/1000 ✅ synthetic/surrounded | Init: 95.35ms | Path: 90.18ms | Dist: 1017142 tiles | Routes: 1000/1000 ✅ synthetic/svalmel | Init: 60.58ms | Path: 104.75ms | Dist: 1235501 tiles | Routes: 1000/1000 ✅ synthetic/twolakes | Init: 62.05ms | Path: 94.54ms | Dist: 1140807 tiles | Routes: 1000/1000 ✅ synthetic/world | Init: 41.43ms | Path: 93.42ms | Dist: 873406 tiles | Routes: 1000/1000 Completed 42 scenarios Total Initialization Time: 2796.32ms Total Pathfinding Time: 5026.64ms Total Distance: 53160274 tiles ``` ## Playground **That's the fun part**. Watch NavMesh running circles around legacy `PathFinder.Mini` in real time. Debug inner workings, test edge cases, share URLs for debugging. https://github.com/user-attachments/assets/34e2e3f5-fbc1-4b1f-917d-820766e98d5d ## Discord Tag `moleole`	2026-01-08 13:34:18 -08:00