Refactor Game Engine Optimization

[candour]

This refactor addresses performance bottlenecks in the core game loop of Hawker Rush. By introducing a SpatialIndex utility using axial coordinate bucketing, we've optimized proximity-based operations such as enemy-puddle interactions and projectile AoE collision detection. These changes reduce the computational complexity from O(N*M) to O(N) per tick, ensuring smoother gameplay as the number of entities increases in later waves. Functional correctness was verified through a new integration test suite and existing regression tests.

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PR created automatically by Jules for task 10193098012678763011 started by @candour

Summary by CodeRabbit

• Refactor

  • Introduced a spatial indexing system to speed up proximity checks, improving collision and AoE handling and reducing runtime work during gameplay.

• Tests

  • Added integration tests validating spatial queries and end-to-end game-update behavior (projectile AoE and enemy removal).

• Documentation

  • Recorded the engine refactor and its performance benefits in the fixes log.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: ee962bb0-3e3d-463c-8948-29dbaa8bf90a

📥 Commits

Reviewing files that changed from the base of the PR and between 541a999 and 36118d4.

📒 Files selected for processing (1)

• app/src/test/java/com/messark/hawker/SpatialIndexIntegrationTest.kt

📝 Walkthrough

Walkthrough

Adds a generic axial-grid SpatialIndex and integrates per-tick spatial indices into MainViewModel.updateGame, replacing full-scan puddle and enemy lookups with localized findNearby queries for puddle effects and projectile AoE resolution.

Changes

Spatial Index + Main loop integration

Layer / File(s)	Summary
SpatialIndex utility implementation app/src/main/java/com/messark/hawker/utils/SpatialIndex.kt	New generic spatial index that buckets entities by integer axial coordinates and exposes findNearby(center: PreciseAxialCoordinate, radius: Float): List<T> using axial-distance filtering.
Per-tick index construction and wiring app/src/main/java/com/messark/hawker/MainViewModel.kt	updateGame now constructs a puddle SpatialIndex after transient updates and an enemy SpatialIndex after enemy movement, and passes them into downstream handlers. Import for SpatialIndex added.
Enemy movement: puddle proximity queries app/src/main/java/com/messark/hawker/MainViewModel.kt	handleEnemyMovement signature changed to accept SpatialIndex<StickyPuddle>; per-enemy checks replace scanning state.puddles with puddleSpatialIndex.findNearby(...) to apply slow/stall effects only for nearby puddles.
Projectiles: AoE collision resolution app/src/main/java/com/messark/hawker/MainViewModel.kt	handleProjectiles signature changed to accept SpatialIndex<Enemy>; AoE hit detection replaces the full state.enemies loop with enemySpatialIndex.findNearby(targetPos, proj.aoeRadius) to gather hits.
Tests and changelog app/src/test/java/com/messark/hawker/SpatialIndexIntegrationTest.kt, fixes.md	New integration test validates SpatialIndex.findNearby and an end-to-end updateGame scenario; fixes.md records REF-009 documenting the refactor.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• candour/towerpower#125: Related changes to puddle/grid distance handling and MainViewModel.handleEnemyMovement.
• candour/towerpower#133: Related changes to projectile AoE/enemy lookup strategies in MainViewModel.handleProjectiles.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Title check	❓ Inconclusive	The title 'Refactor Game Engine Optimization' is vague and overly broad, using non-descriptive terms that don't convey the specific main change (introducing SpatialIndex for spatial partitioning to optimize proximity lookups).	Revise the title to be more specific, such as 'Introduce SpatialIndex for game engine optimization' or 'Optimize proximity lookups with spatial partitioning' to clearly communicate the primary technical change.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor-game-engine-optimization-10193098012678763011

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[github-actions]

Build Successful! 🚀

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[coderabbitai]

Actionable comments posted: 2

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: bfa9e9ef-61fe-4130-ac4d-264a7f7ab186

📥 Commits

Reviewing files that changed from the base of the PR and between a1ed2d2 and cfc0bfc.

📒 Files selected for processing (4)

• app/src/main/java/com/messark/hawker/MainViewModel.kt
• app/src/main/java/com/messark/hawker/utils/SpatialIndex.kt
• app/src/test/java/com/messark/hawker/SpatialIndexIntegrationTest.kt
• fixes.md

[candour]

The enemySpatialIndex is built from state.enemies at their initial positions (line 356), but it's not used until line 375 in handleProjectiles, which occurs after enemy movement updates their positions (lines 368-369). This means projectile AoE collision detection queries the spatial index with stale enemy positions, causing projectiles to potentially miss enemies that have moved since the index was constructed.

[google-labs-jules]

The enemySpatialIndex is built from state.enemies at their initial positions (line 356), but it's not used until line 375 in handleProjectiles, which occurs after enemy movement updates their positions (lines 368-369). This means projectile AoE collision detection queries the spatial index with stale enemy positions, causing projectiles to potentially miss enemies that have moved since the index was constructed.

Thank you for catching this! I've moved the enemySpatialIndex construction to immediately before handleProjectiles to ensure it uses the updated enemy positions after movement. I also took the opportunity to ensure the puddleSpatialIndex is built after transient updates to filter out expired puddles.

[github-actions]

Build Successful! 🚀

Download APK

Note: This link will be removed when the PR is closed.

[github-actions]

Build Successful! 🚀

Download APK

Note: This link will be removed when the PR is closed.