DBot/overdrive_that_matters
DBot/overdrive_that_matters
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Lock CMWC state size to 256 WORDs, improving performance of nextInt()

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This commit is contained in:
DBotThePony 2025-03-03 22:19:57 +07:00
parent 38923d7978
commit fcec612718
Signed by: DBot
GPG Key ID: DCC23B5715498507
1 changed files with 10 additions and 10 deletions
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20
src/main/kotlin/ru/dbotthepony/mc/otm/core/util/CMWCRandom.kt
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@ -7,8 +7,8 @@ import net.minecraft.world.level.levelgen.PositionalRandomFactory
import java.lang.StringBuilder import java.lang.StringBuilder
import java.util.random.RandomGenerator import java.util.random.RandomGenerator
class CMWCRandom(seed: Long = System.nanoTime(), private val stateSize: Int = CMWC_DEFAULT_STATE_SIZE) : RandomGenerator, RandomSource { class CMWCRandom(seed: Long = System.nanoTime()) : RandomGenerator, RandomSource {
private val state = IntArray(stateSize) private val state = IntArray(CMWC_STATE_SIZE)
private var carry = 0 private var carry = 0
private var stateIndex = 0 private var stateIndex = 0
private val gaussian = MarsagliaPolarGaussian(this) private val gaussian = MarsagliaPolarGaussian(this)
@ -37,7 +37,7 @@ class CMWCRandom(seed: Long = System.nanoTime(), private val stateSize: Int = CM
} }
override fun nextInt(): Int { override fun nextInt(): Int {
stateIndex = (stateIndex + 1) % state.size stateIndex = (stateIndex + 1).and(CMWC_STATE_SIZE - 1)
val t = 18782L * state[stateIndex] + carry val t = 18782L * state[stateIndex] + carry
carry = t.ushr(32).toInt() carry = t.ushr(32).toInt()
@ -83,24 +83,24 @@ class CMWCRandom(seed: Long = System.nanoTime(), private val stateSize: Int = CM
} }
override fun fork(): RandomSource { override fun fork(): RandomSource {
return CMWCRandom(nextLong(), stateSize) return CMWCRandom(nextLong())
} }
override fun forkPositional(): PositionalRandomFactory { override fun forkPositional(): PositionalRandomFactory {
return Positional(nextLong(), stateSize) return Positional(nextLong())
} }
class Positional(val seed: Long, val stateSize: Int = CMWC_DEFAULT_STATE_SIZE) : PositionalRandomFactory { class Positional(val seed: Long) : PositionalRandomFactory {
override fun at(x: Int, y: Int, z: Int): RandomSource { override fun at(x: Int, y: Int, z: Int): RandomSource {
return CMWCRandom(Mth.getSeed(x, y, z).xor(seed), stateSize) return CMWCRandom(Mth.getSeed(x, y, z).xor(seed))
} }
override fun fromHashOf(name: String): RandomSource { override fun fromHashOf(name: String): RandomSource {
return CMWCRandom(name.hashCode().toLong().xor(seed), stateSize) return CMWCRandom(name.hashCode().toLong().xor(seed))
} }
override fun fromSeed(seed: Long): RandomSource { override fun fromSeed(seed: Long): RandomSource {
return CMWCRandom(seed, stateSize) return CMWCRandom(seed)
} }
override fun parityConfigString(builder: StringBuilder) { override fun parityConfigString(builder: StringBuilder) {
@ -109,7 +109,7 @@ class CMWCRandom(seed: Long = System.nanoTime(), private val stateSize: Int = CM
} }
companion object { companion object {
const val CMWC_DEFAULT_STATE_SIZE = 256 // 4096 const val CMWC_STATE_SIZE = 256 // 4096
const val CMWC_CARRY_MAX = 809430660 const val CMWC_CARRY_MAX = 809430660
} }
} }