400% performance gain

Author: emyfops

common/src/main/kotlin/com/lambda/util/collections/Extensions.kt

@@ -0,0 +1,21 @@
+package com.lambda.util.collections
+
+/**
+ * Filters elements of the iterable by their runtime type and a predicate, and adds the matching elements to the specified mutable collection.
+ *
+ * This function allows filtering elements of an iterable based on their runtime type and a provided predicate function.
+ * The elements that match both the type constraint and the predicate are added to the destination mutable collection.
+ * Because we do not want additional overhead, this function acts as pointer receiver to a collection.
+ * The predicate function determines whether an element should be included based on its type and any additional criteria.
+ *
+ * @param R The target type to filter elements to.
+ * @param C The type of the destination mutable collection.
+ * @param destination The mutable collection to which the filtered elements will be added.
+ * @param predicate The predicate function that determines whether an element should be included based on its type and other criteria.
+ */
+inline fun <reified R, C : MutableCollection<in R>> Iterable<*>.filterIsInstanceTo(
+    destination: C,
+    predicate: (R) -> Boolean
+) {
+    for (element in this) if (element is R && predicate(element)) destination.add(element)
+}

common/src/main/kotlin/com/lambda/util/world/EntityUtils.kt

@@ -1,6 +1,7 @@
 package com.lambda.util.world
 
 import com.lambda.context.SafeContext
+import com.lambda.util.collections.filterIsInstanceTo
 import net.minecraft.entity.Entity
 import net.minecraft.util.math.ChunkSectionPos
 import net.minecraft.util.math.Vec3d
@@ -48,7 +49,7 @@ object EntityUtils {
         val sectionY = pos.y.toInt() shr 4
         val sectionZ = pos.z.toInt() shr 4
 
-        val entities = mutableListOf<T>()
+        val entities = ArrayList<T>()
 
         // Here we iterate over all sections within the specified distance and add all entities of type [T] to the list.
         // We do not have to worry about performance here, as the number of sections is very limited.
@@ -57,7 +58,7 @@ object EntityUtils {
             for (y in sectionY - chunks..sectionY + chunks) {
                 for (z in sectionZ - chunks..sectionZ + chunks) {
                     val section = world.entityManager.cache.findTrackingSection(ChunkSectionPos.asLong(x, y, z)) ?: continue
-                    entities.addAll(section.collection.getAllOfType(T::class.java).filter(predicate))
+                    section.collection.filterIsInstanceTo(entities, predicate)
                 }
             }
         }