"populate noise" step of chunk generation (#319)

* implement populate noise step of chunk generation

* fix gitignore

* pass thru seed

* add counter for edge case

* add entire chunk test case

* remove eclipse file

* remove packet timing

* precompute float divisions

* unsafe speed up

* slight aquifer optimization

* tweak block pos packing

* optimize perlin map

* precompute aquifer random positions

* fix aquifer regression

* refactor samplers, add tests to aquifer, and move chunk extractor to the extractors

* fix base density function error and add a bunch of test cases

* ignore expensive tests by default

* remove un-needed lifetimes

* remove minecraft prefix from block lookups

* fix populate noise bench

* slight optimizations

* read files at runtime to speed up test compilation speed and remove ignores

* remove new lines from test data so people stop freaking out about line count

* make extractor the same

* leverage branch prediction

---------

Co-authored-by: Alexander Medvedev <[email protected]>

.gitignore

@@ -126,3 +126,7 @@ node_modules
 
 run/
 
+# Benchmarking
+*perf.data*
+*flamegraph.svg
+

Cargo.toml

@@ -26,6 +26,9 @@ opt-level = 1
 lto = true
 codegen-units = 1
 
+[profile.bench]
+debug = true
+
 [profile.profiling]
 inherits = "release"
 debug = true

extractor/build.gradle.kts

@@ -49,6 +49,9 @@ dependencies {
     modImplementation("net.fabricmc:fabric-language-kotlin:${project.property("kotlin_loader_version")}")
 
     modImplementation("net.fabricmc.fabric-api:fabric-api:${project.property("fabric_version")}")
+
+    // To allow for reflection
+    implementation(kotlin("reflect"))
 }
 
 tasks.processResources {

extractor/src/main/kotlin/de/snowii/extractor/Extractor.kt

@@ -1,5 +1,6 @@
 package de.snowii.extractor
 
+import com.google.gson.Gson
 import com.google.gson.GsonBuilder
 import com.google.gson.JsonElement
 import de.snowii.extractor.extractors.*
@@ -32,6 +33,7 @@ class Extractor : ModInitializer {
             Tags(),
             Items(),
             Blocks(),
+            Tests(),
         )
 
         val outputDirectory: Path

extractor/src/main/kotlin/de/snowii/extractor/extractors/Tests.kt

@@ -0,0 +1,142 @@
+
+package de.snowii.extractor.extractors
+
+import com.google.gson.Gson
+import com.google.gson.GsonBuilder
+import com.google.gson.JsonArray
+import com.google.gson.JsonElement
+import de.snowii.extractor.Extractor
+import net.minecraft.block.Block
+import net.minecraft.block.BlockState
+import net.minecraft.block.Blocks
+import net.minecraft.registry.BuiltinRegistries
+import net.minecraft.registry.RegistryKeys
+import net.minecraft.registry.RegistryWrapper
+import net.minecraft.registry.RegistryWrapper.WrapperLookup
+import net.minecraft.registry.entry.RegistryEntry.Reference
+import net.minecraft.server.MinecraftServer
+import net.minecraft.util.math.noise.DoublePerlinNoiseSampler.NoiseParameters
+import net.minecraft.util.math.ChunkPos
+import net.minecraft.world.gen.chunk.AquiferSampler
+import net.minecraft.world.gen.chunk.Blender
+import net.minecraft.world.gen.chunk.ChunkGeneratorSettings
+import net.minecraft.world.gen.chunk.ChunkNoiseSampler
+import net.minecraft.world.gen.chunk.GenerationShapeConfig
+import net.minecraft.world.gen.densityfunction.DensityFunction.NoisePos;
+import net.minecraft.world.gen.densityfunction.DensityFunction.EachApplier;
+import net.minecraft.world.gen.densityfunction.DensityFunctionTypes
+import net.minecraft.world.gen.noise.NoiseConfig
+
+import java.lang.reflect.Method
+import java.util.Arrays
+import kotlin.reflect.full.createType
+import kotlin.reflect.full.declaredFunctions
+import kotlin.reflect.jvm.javaMethod
+import kotlin.reflect.KFunction
+
+class Tests : Extractor.Extractor {
+    override fun fileName(): String = "chunk.json"
+
+	private fun createFluidLevelSampler(settings: ChunkGeneratorSettings): AquiferSampler.FluidLevelSampler {
+		val fluidLevel = AquiferSampler.FluidLevel(-54, Blocks.LAVA.getDefaultState());
+		val i = settings.seaLevel();
+		val fluidLevel2 = AquiferSampler.FluidLevel(i, settings.defaultFluid());
+		return AquiferSampler.FluidLevelSampler {_, y, _ -> if (y < Math.min(-54, i)) fluidLevel else fluidLevel2};
+	}
+
+	private fun get_index(config: GenerationShapeConfig, x: Int, y: Int, z: Int): Int {
+		if (x < 0 || y < 0 || z < 0) {
+			System.err.println("Bad local pos");
+			System.exit(1);
+		}
+		return config.height() * 16 * x + 16 * y + z
+	}
+
+	// This is basically just what NoiseChunkGenerator is doing
+	private fun populate_noise(start_x: Int, start_z: Int, sampler: ChunkNoiseSampler, config: GenerationShapeConfig, settings: ChunkGeneratorSettings): IntArray? {
+		val result = IntArray(16 * 16 * config.height())
+
+		for (method: KFunction<*> in sampler::class.declaredFunctions) {
+			if (method.name.equals("sampleBlockState")) {
+				sampler.sampleStartDensity()
+				val k = config.horizontalCellBlockCount()
+				val l = config.verticalCellBlockCount()
+
+				val m = 16 / k
+				val n = 16 / k
+
+				val cellHeight = config.height() / l
+				val minimumCellY = config.minimumY() / l
+
+				for (o in 0..<m) {
+					sampler.sampleEndDensity(o)
+					for (p in 0..<n) {
+						for (r in (0..<cellHeight).reversed()) {
+							sampler.onSampledCellCorners(r, p)
+							for (s in (0..<l).reversed()) {
+								val t = (minimumCellY + r) * l + s
+								val d = s.toDouble() / l.toDouble()
+								sampler.interpolateY(t, d)
+								for (w in 0..<k) {
+									val x = start_x + o * k + w
+									val y = x and 15
+									val e = w.toDouble() / k.toDouble()
+									sampler.interpolateX(x, e)
+									for (z in 0..<k) {
+										val aa = start_z + p * k + z
+										val ab = aa and 15
+										val f = z.toDouble() / k.toDouble()
+										sampler.interpolateZ(aa, f)
+										var blockstate = method.call(sampler) as BlockState?
+										if (blockstate == null) {
+											blockstate = settings.defaultBlock()
+										}
+										val index = this.get_index(config, y, t - config.minimumY(), ab)
+										result[index] = Block.getRawIdFromState(blockstate)
+									}
+								}
+							}
+						}
+					}
+					sampler.swapBuffers()
+				}
+				sampler.stopInterpolation()
+				return result
+			}
+		}
+		System.err.println("No valid method found for block state sampler!");
+		return null;
+	}
+
+    // Dumps a chunk to an array of block state ids
+    override fun extract(server: MinecraftServer): JsonElement {
+        val topLevelJson = JsonArray()
+		val seed = 0L
+		val chunk_pos = ChunkPos(7, 4)
+
+		val lookup = BuiltinRegistries.createWrapperLookup()
+		val wrapper = lookup.getOrThrow(RegistryKeys.CHUNK_GENERATOR_SETTINGS)
+		val noise_params = lookup.getOrThrow(RegistryKeys.NOISE_PARAMETERS)
+
+		val ref = wrapper.getOrThrow(ChunkGeneratorSettings.OVERWORLD)
+		val settings = ref.value()
+		val config = NoiseConfig.create(settings, noise_params, seed)
+
+		// Overworld shape config
+		val shape = GenerationShapeConfig(-64, 384, 1, 2)
+		val test_sampler = ChunkNoiseSampler(16 / shape.horizontalCellBlockCount(), config, chunk_pos.startX, chunk_pos.startZ,
+		shape, object: DensityFunctionTypes.Beardifying{
+			override fun maxValue(): Double = 0.0
+			override fun minValue(): Double = 0.0
+			override fun sample(pos: NoisePos): Double = 0.0
+			override fun fill(densities: DoubleArray, applier: EachApplier) {densities.fill(0.0)}
+		}, settings, createFluidLevelSampler(settings), Blender.getNoBlending())
+
+		val data = populate_noise(chunk_pos.startX, chunk_pos.startZ, test_sampler, shape, settings)
+		data?.forEach { state ->
+            topLevelJson.add(state)
+        }
+
+        return topLevelJson
+    }
+}

pumpkin-core/Cargo.toml

@@ -13,3 +13,4 @@ num-derive.workspace = true
 colored = "2"
 md5 = "0.7.0"
 
+enum_dispatch = "0.3.13"

pumpkin-core/src/lib.rs

@@ -21,3 +21,12 @@ pub enum ProfileAction {
     ForcedNameChange,
     UsingBannedSkin,
 }
+
+#[macro_export]
+macro_rules! assert_eq_delta {
+    ($x:expr, $y:expr, $d:expr) => {
+        if !(2f64 * ($x - $y).abs() <= $d * ($x.abs() + $y.abs())) {
+            panic!("{} vs {} ({} vs {})", $x, $y, ($x - $y).abs(), $d);
+        }
+    };
+}

pumpkin-core/src/math/mod.rs

@@ -1,3 +1,5 @@
+use num_traits::PrimInt;
+
 pub mod boundingbox;
 pub mod position;
 pub mod vector2;
@@ -30,3 +32,60 @@ pub fn magnitude(a: f64, b: f64, c: f64) -> f64 {
 pub const fn get_section_cord(coord: i32) -> i32 {
     coord >> 4
 }
+
+const MULTIPLY_DE_BRUIJN_BIT_POSITION: [u8; 32] = [
+    0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, 31, 27, 13, 23, 21, 19, 16, 7, 26,
+    12, 18, 6, 11, 5, 10, 9,
+];
+
+/// Maximum return value: 31
+pub const fn ceil_log2(value: u32) -> u8 {
+    let value = if value.is_power_of_two() {
+        value
+    } else {
+        smallest_encompassing_power_of_two(value)
+    };
+
+    MULTIPLY_DE_BRUIJN_BIT_POSITION[(((value as usize) * 125613361) >> 27) & 31]
+}
+
+/// Maximum return value: 30
+pub const fn floor_log2(value: u32) -> u8 {
+    ceil_log2(value) - if value.is_power_of_two() { 0 } else { 1 }
+}
+
+pub const fn smallest_encompassing_power_of_two(value: u32) -> u32 {
+    let mut i = value - 1;
+    i |= i >> 1;
+    i |= i >> 2;
+    i |= i >> 4;
+    i |= i >> 8;
+    i |= i >> 16;
+    i + 1
+}
+
+#[inline]
+pub fn floor_div<T>(x: T, y: T) -> T
+where
+    T: PrimInt + From<i8>,
+{
+    let div = x / y;
+    if (x ^ y) < 0.into() && div * y != x {
+        div - 1.into()
+    } else {
+        div
+    }
+}
+
+#[inline]
+pub fn floor_mod<T>(x: T, y: T) -> T
+where
+    T: PrimInt + From<i8>,
+{
+    let rem = x % y;
+    if (x ^ y) < 0.into() && rem != 0.into() {
+        rem + y
+    } else {
+        rem
+    }
+}

pumpkin-core/src/math/vector2.rs

@@ -4,14 +4,14 @@ use num_traits::Float;
 
 use super::vector3::Vector3;
 
-#[derive(Clone, Copy, Debug, PartialEq, Hash, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Hash, Eq, Default)]
 pub struct Vector2<T> {
     pub x: T,
     pub z: T,
 }
 
 impl<T: Math + Copy> Vector2<T> {
-    pub fn new(x: T, z: T) -> Self {
+    pub const fn new(x: T, z: T) -> Self {
         Vector2 { x, z }
     }
 
@@ -114,3 +114,4 @@ impl Math for f64 {}
 impl Math for f32 {}
 impl Math for i32 {}
 impl Math for i64 {}
+impl Math for i8 {}

pumpkin-core/src/math/vector3.rs

@@ -1,8 +1,8 @@
-use std::ops::{Add, Div, Mul, Neg, Sub};
+use std::ops::{Add, Div, Mul, Sub};
 
 use num_traits::Float;
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Hash, Eq, Default)]
 pub struct Vector3<T> {
     pub x: T,
     pub y: T,
@@ -80,6 +80,7 @@ impl<T: Math + Copy> Add for Vector3<T> {
     }
 }
 
+/*
 impl<T: Math + Copy> Neg for Vector3<T> {
     type Output = Self;
 
@@ -91,6 +92,7 @@ impl<T: Math + Copy> Neg for Vector3<T> {
         }
     }
 }
+*/
 
 impl<T> From<(T, T, T)> for Vector3<T> {
     #[inline(always)]
@@ -108,7 +110,7 @@ impl<T> From<Vector3<T>> for (T, T, T) {
 
 pub trait Math:
     Mul<Output = Self>
-    + Neg<Output = Self>
+    //+ Neg<Output = Self>
     + Add<Output = Self>
     + Div<Output = Self>
     + Sub<Output = Self>
@@ -119,3 +121,4 @@ impl Math for f64 {}
 impl Math for f32 {}
 impl Math for i32 {}
 impl Math for i64 {}
+impl Math for u8 {}