Fix hash grid

[abcxff]

Why:

Fixes dup ticks & hash grid

Summarize what's being changed (include any screenshots, code, or other media if available):

Confirm the following:

• I have tested these changes (by compiling, running, and playing) and have seen no unintended differences in gameplay

[Copilot]

Pull request overview

This pull request fixes duplicate entity ticks and corrects the hash grid implementation. The changes address critical bugs in the collision detection system and entity management that could cause incorrect game behavior.

Changes:

• Fixed hash grid collision pair tracking by implementing triangular matrix indexing, reducing memory usage from O(n²) to O(n²/2)
• Corrected hash multiplier calculation in the spatial hash grid by removing an erroneous bit shift operation
• Prevented duplicate tick() calls for CameraEntity instances by adding proper type checking in the entity manager
• Cleaned up unused imports and fixed property access patterns

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
src/Physics/HashGrid.ts	Refactored collision pair deduplication to use triangular matrix indexing, fixed hash multiplier calculation, corrected positionData access, and improved error messages
src/Native/Manager.ts	Added type guards to prevent CameraEntity from being ticked twice (once in main loop and once in dedicated camera loop)
src/Entity/Misc/Mothership.ts	Removed unused ArenaEntity import, keeping only the used ArenaState export

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[Copilot]

The comment says "row * (row - 1) / 2 + col" but the actual formula uses idB and idA. For clarity, consider updating the comment to match the variable names: "Triangular matrix index: idB * (idB - 1) / 2 + idA, where idB > idA".

Suggested change

	// Triangular matrix index: row * (row - 1) / 2 + col, where row > col
	// Triangular matrix index: idB * (idB - 1) / 2 + idA, where idB > idA

[Copilot]

The triangular index calculation uses JavaScript division which returns a floating-point number. For correctness and to avoid potential precision issues with large IDs, consider using integer division explicitly. Replace line 221 with: const triangularIndex = Math.floor(idB * (idB - 1) / 2) + idA; or use bit shifting for the division by 2: const triangularIndex = ((idB * (idB - 1)) >> 1) + idA;. While the current implementation will likely work, explicit integer operations make the intent clearer and avoid relying on JavaScript's automatic conversion to 32-bit integers during bitwise operations.

Suggested change

	const triangularIndex = (idB * (idB - 1) / 2 + idA);
	const triangularIndex = Math.floor(idB * (idB - 1) / 2) + idA;

[Copilot]

The error message says "Cannot forEachCollisionPair() entity outside of tick" but it should probably be "Cannot call forEachCollisionPair() outside of tick" (without the word "entity") to match the pattern of the other error messages and be grammatically correct.

Suggested change

	if (this.isLocked) throw new Error("HashGrid is locked! Cannot forEachCollisionPair() entity outside of tick");
	if (this.isLocked) throw new Error("HashGrid is locked! Cannot call forEachCollisionPair() outside of tick");

[c86ec23b-fef1-4979-b2fa-b9adc351b8cc]

Should probably work