From 97d30d3a19dd61352fdb693680e2167e4b01aedf Mon Sep 17 00:00:00 2001
From: DBotThePony <dbotthepony@yandex.ru>
Date: Sun, 2 Mar 2025 11:33:28 +0700
Subject: [PATCH] Add seed mix to enormous placements

---
 src/data/kotlin/ru/dbotthepony/mc/otm/datagen/WorldGen.kt  | 3 ++-
 .../mc/otm/worldgen/placement/AbstractEnormousPlacement.kt | 7 ++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/WorldGen.kt b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/WorldGen.kt
index a2e805f68..df638c7d2 100644
--- a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/WorldGen.kt
+++ b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/WorldGen.kt
@@ -121,11 +121,12 @@ fun registerPlacedFeatures(context: BootstrapContext<PlacedFeature>) {
 				EnormousEllipsoidPlacement(
 					parameters = AbstractEnormousPlacement.Parameters(
 						chunkScanRange = 5,
+						seedMix = 237483209523709234L,
 						placementModifiers = listOf(
 							RarityFilter.onAverageOnceEvery(120),
 							InSquarePlacement.spread(),
 							HeightRangePlacement.of(StandardDeviationHeightProvider(VerticalAnchor.absolute(0), 15.0)),
-						)
+						),
 					),
 					x = ringularity,
 					y = ringularity,
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/worldgen/placement/AbstractEnormousPlacement.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/worldgen/placement/AbstractEnormousPlacement.kt
index 6c453cda4..4180a3afc 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/worldgen/placement/AbstractEnormousPlacement.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/worldgen/placement/AbstractEnormousPlacement.kt
@@ -34,6 +34,7 @@ abstract class AbstractEnormousPlacement(val parameters: Parameters) : Placement
 		 * Too small value will cause placement cutoffs
 		 */
 		val chunkScanRange: Int,
+		val seedMix: Long,
 
 		/**
 		 * Baseline placement modifiers, dictating how to appear in chunk
@@ -42,12 +43,14 @@ abstract class AbstractEnormousPlacement(val parameters: Parameters) : Placement
 	)
 
 	private class GeneratedChunk(positions: Stream<BlockPos>) {
+		// TODO: memory inefficient
 		private val positions = ArrayList<BlockPos>()
 
 		init {
 			positions.forEach { this.positions.add(it) }
 		}
 
+		// TODO: this is primitive implementation, need to implement better one
 		fun getPositions(pos: ChunkPos): Stream<BlockPos> {
 			return positions.stream().filter {
 				SectionPos.blockToSectionCoord(it.x) == pos.x &&
@@ -67,7 +70,8 @@ abstract class AbstractEnormousPlacement(val parameters: Parameters) : Placement
 		.build<ChunkPos, GeneratedChunk>()
 
 	private fun computeChunk(context: PlacementContext, pos: ChunkPos): GeneratedChunk {
-		val random = RandomSource.create(context.level.seed + HashCommon.murmurHash3(pos.x + pos.z * 31))
+		// TODO: Maybe switch to something else other than original LCG PRNG? Original form of LCG is kinda bad for this kind of workload
+		val random = RandomSource.create(context.level.seed + HashCommon.murmurHash3(pos.x + pos.z * 31) + parameters.seedMix)
 		var stream = Stream.of(BlockPos(pos.minBlockX, 0, pos.minBlockZ))
 		parameters.placementModifiers.forEach { modifier -> stream = stream.flatMap { modifier.getPositions(context, random, it).sequential() } }
 		return GeneratedChunk(stream.flatMap { getPositions(it, random) })
@@ -97,6 +101,7 @@ abstract class AbstractEnormousPlacement(val parameters: Parameters) : Placement
 		val PARAMETERS_CODEC: MapCodec<Parameters> = RecordCodecBuilder.mapCodec {
 			it.group(
 				Codec.INT.minRange(0).fieldOf("chunk_scan_range").forGetter(Parameters::chunkScanRange),
+				Codec.LONG.fieldOf("seed_mix").forGetter(Parameters::seedMix),
 				CODEC.listOf().fieldOf("placement").forGetter(Parameters::placementModifiers),
 			).apply(it, ::Parameters)
 		}