From 884a4326768e6207aca2b1a4a470d4618ed3c76f Mon Sep 17 00:00:00 2001
From: DBotThePony <dbotthepony@yandex.ru>
Date: Wed, 1 May 2024 11:59:04 +0700
Subject: [PATCH] Make EntityIndex#walk significantly faster when querying
 large regions

---
 .../kstarbound/world/EntityIndex.kt           | 27 ++++++++++++++-----
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/main/kotlin/ru/dbotthepony/kstarbound/world/EntityIndex.kt b/src/main/kotlin/ru/dbotthepony/kstarbound/world/EntityIndex.kt
index 16bcb4d0..a002bc1e 100644
--- a/src/main/kotlin/ru/dbotthepony/kstarbound/world/EntityIndex.kt
+++ b/src/main/kotlin/ru/dbotthepony/kstarbound/world/EntityIndex.kt
@@ -1,6 +1,7 @@
 package ru.dbotthepony.kstarbound.world
 
 import it.unimi.dsi.fastutil.ints.IntAVLTreeSet
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet
 import it.unimi.dsi.fastutil.longs.Long2ObjectFunction
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap
 import it.unimi.dsi.fastutil.longs.LongArrayList
@@ -317,7 +318,7 @@ class EntityIndex(val geometry: WorldGeometry) {
 	}
 
 	fun <V> walk(rect: AABB, visitor: (AbstractEntity) -> KOptional<V>, withEdges: Boolean = true): KOptional<V> {
-		val seen = IntAVLTreeSet()
+		val seen = IntOpenHashSet(256)
 
 		for (actualRegion in geometry.split(rect).first) {
 			val xMin = geometry.x.chunkFromCell(actualRegion.mins.x)
@@ -327,15 +328,29 @@ class EntityIndex(val geometry: WorldGeometry) {
 			val yMax = geometry.y.chunkFromCell(actualRegion.maxs.y)
 
 			for (x in xMin .. xMax) {
+				val xIsEdge = x == xMin || x == xMax
+
 				for (y in yMin .. yMax) {
 					val sector = map[index(x, y)] ?: continue
+					val yIsEdge = y == yMin || y == yMax
 
-					for (entry in sector.entries) {
-						if (seen.add(entry.id) && entry.intersects(actualRegion, withEdges)) {
-							val visit = visitor(entry.value)
+					if (!xIsEdge && !yIsEdge) {
+						for (entry in sector.entries) {
+							if (seen.add(entry.id)) {
+								val visit = visitor(entry.value)
 
-							if (visit.isPresent)
-								return visit
+								if (visit.isPresent)
+									return visit
+							}
+						}
+					} else {
+						for (entry in sector.entries) {
+							if (seen.add(entry.id) && entry.intersects(actualRegion, withEdges)) {
+								val visit = visitor(entry.value)
+
+								if (visit.isPresent)
+									return visit
+							}
 						}
 					}
 				}