From 4431e257a2bee2f82955e964660edad7059bb00b Mon Sep 17 00:00:00 2001
From: RicardoDeZoete <ricardo.dezoete@snappet.org>
Date: Thu, 5 Mar 2026 17:52:54 +0100
Subject: [PATCH] perf(client): cache parsed chunk/batch origin coordinates
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chunkIdToOriginCoordinate() and batchIdToBatchOrigin() are called in
hot per-frame loops (view distance culling, batch sorting, light
volumes).  Each call does split(',') + .map(Number) which allocates
an intermediate array, a closure, a mapped array, and an {x,y,z}
object — 5 allocations per call.

With ~200 active batches, applyBatchViewDistance() alone produces
~1 000 throwaway objects per frame.  Add a Map<string, Vector3Like>
cache for each method so the parsing and allocation happen only once
per unique ID.  All existing callers are read-only so caching the
returned objects is safe.

Made-with: Cursor
---
 client/src/chunks/Chunk.ts | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/client/src/chunks/Chunk.ts b/client/src/chunks/Chunk.ts
index d0d2a50c..c6e03e11 100644
--- a/client/src/chunks/Chunk.ts
+++ b/client/src/chunks/Chunk.ts
@@ -12,6 +12,12 @@ export interface LightSource {
 // Working variables
 const vec3like: Vector3LikeMutable = { x: 0, y: 0, z: 0 };
 
+// Caches for parsed string-ID → numeric-origin lookups.
+// These are called in hot per-frame loops (view distance, sorting, culling).
+// Each uncached call does split(',') + .map(Number) — 5 allocations per call.
+const chunkOriginCache = new Map<ChunkId, Vector3Like>();
+const batchOriginCache = new Map<BatchId, Vector3Like>();
+
 export default class Chunk {
   public readonly originCoordinate: Vector3Like;
   private _chunkId: ChunkId;
@@ -44,8 +50,13 @@ export default class Chunk {
   }
 
   public static chunkIdToOriginCoordinate(chunkId: ChunkId): Vector3Like {
-    const [x, y, z] = chunkId.split(',').map(str => Number(str)) as [number, number, number];
-    return { x, y, z };
+    let cached = chunkOriginCache.get(chunkId);
+    if (!cached) {
+      const [x, y, z] = chunkId.split(',').map(str => Number(str)) as [number, number, number];
+      cached = { x, y, z };
+      chunkOriginCache.set(chunkId, cached);
+    }
+    return cached;
   }
 
   public static originCoordinateToChunkId(originCoordinate: Vector3Like): ChunkId {
@@ -89,8 +100,13 @@ export default class Chunk {
   }
 
   public static batchIdToBatchOrigin(batchId: BatchId): Vector3Like {
-    const [x, y, z] = batchId.split(',').map(str => Number(str)) as [number, number, number];
-    return { x, y, z };
+    let cached = batchOriginCache.get(batchId);
+    if (!cached) {
+      const [x, y, z] = batchId.split(',').map(str => Number(str)) as [number, number, number];
+      cached = { x, y, z };
+      batchOriginCache.set(batchId, cached);
+    }
+    return cached;
   }
 
   // Get all chunk IDs that belong to a batch (some may not exist in world)