Better tritanium ore placement

src/data/kotlin/ru/dbotthepony/mc/otm/datagen/WorldGen.kt

@@ -11,6 +11,7 @@ import net.minecraft.world.level.levelgen.VerticalAnchor
 import net.minecraft.world.level.levelgen.feature.ConfiguredFeature
 import net.minecraft.world.level.levelgen.feature.Feature
 import net.minecraft.world.level.levelgen.feature.configurations.OreConfiguration
+import net.minecraft.world.level.levelgen.heightproviders.VeryBiasedToBottomHeight
 import net.minecraft.world.level.levelgen.placement.CountPlacement
 import net.minecraft.world.level.levelgen.placement.HeightRangePlacement
 import net.minecraft.world.level.levelgen.placement.InSquarePlacement
@@ -19,6 +20,7 @@ import net.minecraft.world.level.levelgen.structure.templatesystem.TagMatchTest
 import net.neoforged.neoforge.common.world.BiomeModifier
 import net.neoforged.neoforge.registries.NeoForgeRegistries
 import ru.dbotthepony.mc.otm.core.math.Decimal
+import ru.dbotthepony.mc.otm.data.world.StandardDeviationHeightProvider
 import ru.dbotthepony.mc.otm.registry.MBlocks
 import ru.dbotthepony.mc.otm.registry.MWorldGenFeatures
 import ru.dbotthepony.mc.otm.worldgen.feature.BlackHolePlacerFeature
@@ -63,18 +65,18 @@ fun registerPlacedFeatures(context: BootstrapContext<PlacedFeature>) {
 	context.register(PlacedFeatures.NORMAL_TRITANIUM, PlacedFeature(
 		ore,
 		listOf(
-			CountPlacement.of(8),
+			CountPlacement.of(6),
 			InSquarePlacement.spread(),
-			HeightRangePlacement.triangle(VerticalAnchor.absolute(0), VerticalAnchor.absolute(50))
+			HeightRangePlacement.of(StandardDeviationHeightProvider(VerticalAnchor.absolute(10), 15.0))
 		)
 	))
 
 	context.register(PlacedFeatures.DEEP_TRITANIUM, PlacedFeature(
 		ore,
 		listOf(
-			CountPlacement.of(10),
+			CountPlacement.of(12),
 			InSquarePlacement.spread(),
-			HeightRangePlacement.uniform(VerticalAnchor.aboveBottom(8), VerticalAnchor.absolute(0))
+			HeightRangePlacement.of(VeryBiasedToBottomHeight.of(VerticalAnchor.aboveBottom(4), VerticalAnchor.absolute(0), 16))
 		)
 	))
 
@@ -83,7 +85,7 @@ fun registerPlacedFeatures(context: BootstrapContext<PlacedFeature>) {
 	context.register(PlacedFeatures.BLACK_HOLE, PlacedFeature(
 		blackHole,
 		listOf(
-			CountPlacement.of(1),
+			InSquarePlacement.spread(),
 			HeightRangePlacement.uniform(VerticalAnchor.absolute(64), VerticalAnchor.absolute(128))
 		)
 	))

src/main/kotlin/ru/dbotthepony/mc/otm/OverdriveThatMatters.kt

@@ -98,6 +98,7 @@ object OverdriveThatMatters {
 		MStats.register(MOD_BUS)
 		MWorldGenFeatures.register(MOD_BUS)
 		CommandArgumentTypes.register(MOD_BUS)
+		MHeightProviders.register(MOD_BUS)
 
 		StorageStack.Companion.register(MOD_BUS)
 		MatteryChestMenu.Companion.register(MOD_BUS)

src/main/kotlin/ru/dbotthepony/mc/otm/core/Ext.kt

@@ -65,6 +65,8 @@ import java.util.stream.Stream
 import java.util.stream.StreamSupport
 import kotlin.NoSuchElementException
 import kotlin.jvm.optionals.getOrNull
+import kotlin.math.ln
+import kotlin.math.sqrt
 import kotlin.reflect.KProperty
 
 operator fun RecipeInput.get(index: Int): ItemStack = getItem(index)
@@ -592,3 +594,45 @@ infix fun FluidStack.isSameAs(other: FluidStack): Boolean {
 infix fun FluidStack.isNotSameAs(other: FluidStack): Boolean {
 	return !FluidStack.isSameFluidSameComponents(this, other) && amount == other.amount
 }
+
+data class DoublePair(val first: Double, val second: Double)
+
+// normal distribution via Box-Muller
+fun RandomGenerator.nextNormalDouble(stddev: Double, mean: Double): DoublePair {
+	var rand1: Double
+	var rand2: Double
+	var distSqr: Double
+
+	do {
+		rand1 = 2.0 * nextDouble() - 1.0
+		rand2 = 2.0 * nextDouble() - 1.0
+		distSqr = rand1 * rand1 + rand2 * rand2
+	} while (distSqr >= 1)
+
+	val mapping = sqrt(-2.0 * ln(distSqr) / distSqr)
+
+	return DoublePair(
+		rand1 * mapping * stddev + mean,
+		rand2 * mapping * stddev + mean
+	)
+}
+
+// this kinda exists in form of nextGaussian, but it doesn't allow to specify deviation and mean
+fun RandomSource.nextNormalDouble(stddev: Double, mean: Double): DoublePair {
+	var rand1: Double
+	var rand2: Double
+	var distSqr: Double
+
+	do {
+		rand1 = 2.0 * nextDouble() - 1.0
+		rand2 = 2.0 * nextDouble() - 1.0
+		distSqr = rand1 * rand1 + rand2 * rand2
+	} while (distSqr >= 1)
+
+	val mapping = sqrt(-2.0 * ln(distSqr) / distSqr)
+
+	return DoublePair(
+		rand1 * mapping * stddev + mean,
+		rand2 * mapping * stddev + mean
+	)
+}

src/main/kotlin/ru/dbotthepony/mc/otm/data/world/StandardDeviationHeightProvider.kt

@@ -0,0 +1,64 @@
+package ru.dbotthepony.mc.otm.data.world
+
+import com.mojang.serialization.Codec
+import com.mojang.serialization.MapCodec
+import com.mojang.serialization.codecs.RecordCodecBuilder
+import net.minecraft.util.RandomSource
+import net.minecraft.world.level.levelgen.VerticalAnchor
+import net.minecraft.world.level.levelgen.WorldGenerationContext
+import net.minecraft.world.level.levelgen.heightproviders.HeightProvider
+import net.minecraft.world.level.levelgen.heightproviders.HeightProviderType
+import org.apache.logging.log4j.LogManager
+import ru.dbotthepony.mc.otm.core.nextNormalDouble
+import ru.dbotthepony.mc.otm.data.minRange
+import ru.dbotthepony.mc.otm.registry.MHeightProviders
+
+/**
+ * Doubles generated are rounded into integers towards negative infinity
+ */
+data class StandardDeviationHeightProvider(
+	val mean: VerticalAnchor,
+	val deviation: Double,
+) : HeightProvider() {
+	override fun sample(random: RandomSource, context: WorldGenerationContext): Int {
+		val y = mean.resolveY(context)
+		val yd = y.toDouble()
+		var i = 100
+
+		while (i-- > 0) {
+			val (r0, r1) = random.nextNormalDouble(deviation, yd)
+			val i0 = r0.toInt()
+			val i1 = r1.toInt()
+
+			if (i0 in context.minGenY .. context.genDepth) {
+				return i0
+			} else if (i1 in context.minGenY .. context.genDepth) {
+				return i1
+			}
+		}
+
+		if (LOGGER.isDebugEnabled) {
+			LOGGER.debug("StandardDeviationHeightProvider couldn't find proper height value for mean $mean with deviation of $deviation")
+		}
+
+		// failsafe
+		return y
+	}
+
+	override fun getType(): HeightProviderType<*> {
+		return MHeightProviders.STANDARD_DEVIATION
+	}
+
+	companion object {
+		private val LOGGER = LogManager.getLogger()
+
+		val CODEC: MapCodec<StandardDeviationHeightProvider> by lazy {
+			RecordCodecBuilder.mapCodec {
+				it.group(
+					VerticalAnchor.CODEC.fieldOf("mean").forGetter(StandardDeviationHeightProvider::mean),
+					Codec.DOUBLE.minRange(1.0).fieldOf("deviation").forGetter(StandardDeviationHeightProvider::deviation),
+				).apply(it, ::StandardDeviationHeightProvider)
+			}
+		}
+	}
+}

src/main/kotlin/ru/dbotthepony/mc/otm/registry/MHeightProviders.kt

@@ -0,0 +1,16 @@
+package ru.dbotthepony.mc.otm.registry
+
+import net.minecraft.core.registries.BuiltInRegistries
+import net.minecraft.world.level.levelgen.heightproviders.HeightProviderType
+import net.neoforged.bus.api.IEventBus
+import ru.dbotthepony.mc.otm.data.world.StandardDeviationHeightProvider
+
+object MHeightProviders {
+	private val registry = MDeferredRegister(BuiltInRegistries.HEIGHT_PROVIDER_TYPE)
+
+	fun register(bus: IEventBus) {
+		registry.register(bus)
+	}
+
+	val STANDARD_DEVIATION by registry.register("standard_deviation") { HeightProviderType { StandardDeviationHeightProvider.CODEC } }
+}