[WIP] start 1.15 port

reorganize packages to match Fabric version
use util classes from Fabric version

src/main/kotlin/mods/betterfoliage/util/Caching.kt

@@ -0,0 +1,60 @@
+package mods.betterfoliage.util
+
+import java.lang.ref.WeakReference
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+interface Invalidator {
+    fun invalidate() {
+        val iterator = callbacks.iterator()
+        while(iterator.hasNext()) iterator.next().let { callback ->
+            callback.get()?.invoke() ?: iterator.remove()
+        }
+    }
+    val callbacks: MutableList<WeakReference<()->Unit>>
+    fun onInvalidate(callback: ()->Unit) {
+        callbacks.add(WeakReference(callback))
+    }
+}
+
+class LazyInvalidatable<V>(invalidator: Invalidator, val valueFactory: ()->V): ReadOnlyProperty<Any, V> {
+    init { invalidator.onInvalidate { value = null } }
+
+    var value: V? = null
+
+    override fun getValue(thisRef: Any, property: KProperty<*>): V {
+        value?.let { return it }
+        return synchronized(this) {
+            value?.let { return it }
+            valueFactory().apply { value = this }
+        }
+    }
+}
+
+class LazyMap<K, V>(val invalidator: Invalidator, val valueFactory: (K)->V) {
+    init { invalidator.onInvalidate { values.clear() } }
+
+    val values = mutableMapOf<K, V>()
+
+    operator fun get(key: K): V {
+        values[key]?.let { return it }
+        return synchronized(values) {
+            values[key]?.let { return it }
+            valueFactory(key).apply { values[key] = this }
+        }
+    }
+    operator fun set(key: K, value: V) { values[key] = value }
+
+    fun delegate(key: K) = Delegate(key)
+
+    inner class Delegate(val key: K) : ReadOnlyProperty<Any, V> {
+        init { invalidator.onInvalidate { cached = null } }
+
+        private var cached: V? = null
+
+        override fun getValue(thisRef: Any, property: KProperty<*>): V {
+            cached?.let { return it }
+            get(key).let { cached = it; return it }
+        }
+    }
+}

src/main/kotlin/mods/betterfoliage/util/Collections.kt

@@ -0,0 +1,63 @@
+package mods.betterfoliage.util
+
+import java.util.*
+
+/**
+ * Starting with the second element of this [Iterable] until the last, call the supplied lambda with
+ * the parameters (index, element, previous element).
+ */
+inline fun <reified T> Iterable<T>.forEachPairIndexed(func: (Int, T, T)->Unit) {
+    var previous: T? = null
+    forEachIndexed { idx, current ->
+        if (previous != null) func(idx, current, previous!!)
+        previous = current
+    }
+}
+
+inline fun <T, C: Comparable<C>> Pair<T, T>.minBy(func: (T)->C) =
+    if (func(first) < func(second)) first else second
+
+inline fun <T, C: Comparable<C>> Pair<T, T>.maxBy(func: (T)->C) =
+    if (func(first) > func(second)) first else second
+
+inline fun <T, C: Comparable<C>> Triple<T, T, T>.maxValueBy(func: (T)->C): C {
+    var result = func(first)
+    func(second).let { if (it > result) result = it }
+    func(third).let { if (it > result) result = it }
+    return result
+}
+
+@Suppress("UNCHECKED_CAST")
+inline fun <K, V> Map<K, V?>.filterValuesNotNull() = filterValues { it != null } as Map<K, V>
+
+inline fun <reified T, R> Iterable<T>.findFirst(func: (T)->R?): R? {
+    forEach { func(it)?.let { return it } }
+    return null
+}
+
+inline fun <A1, reified A2, B> List<Pair<A1, B>>.filterIsInstanceFirst(cls: Class<A2>) = filter { it.first is A2 } as List<Pair<A2, B>>
+
+/** Cross product of this [Iterable] with the parameter. */
+fun <A, B> Iterable<A>.cross(other: Iterable<B>) = flatMap { a -> other.map { b -> a to b } }
+
+inline fun <C, R, T> Iterable<T>.mapAs(transform: (C) -> R) = map { transform(it as C) }
+
+inline fun <T1, T2> forEachNested(list1: Iterable<T1>, list2: Iterable<T2>, func: (T1, T2)-> Unit) =
+    list1.forEach { e1 ->
+        list2.forEach { e2 ->
+            func(e1, e2)
+        }
+    }
+
+/** Mutating version of _map_. Replace each element of the list with the result of the given transformation. */
+inline fun <reified T> MutableList<T>.replace(transform: (T) -> T) = forEachIndexed { idx, value -> this[idx] = transform(value) }
+
+/** Exchange the two elements of the list with the given indices */
+inline fun <T> MutableList<T>.exchange(idx1: Int, idx2: Int) {
+    val e = this[idx1]
+    this[idx1] = this[idx2]
+    this[idx2] = e
+}
+
+/** Return a random element from the array using the provided random generator */
+inline operator fun <T> Array<T>.get(random: Random) = get(random.nextInt(Int.MAX_VALUE) % size)

src/main/kotlin/mods/betterfoliage/util/Futures.kt

@@ -0,0 +1,15 @@
+package mods.betterfoliage.util
+
+import net.minecraft.client.Minecraft
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.CompletionStage
+import java.util.function.Consumer
+import java.util.function.Function
+
+fun completedVoid() = CompletableFuture.completedFuture<Void>(null)!!
+
+fun <T, U> CompletionStage<T>.map(func: (T)->U) = thenApply(Function(func)).toCompletableFuture()!!
+fun <T, U> CompletionStage<T>.mapAsync(func: (T)->U) = thenApplyAsync(Function(func), Minecraft.getInstance()).toCompletableFuture()!!
+
+fun <T> CompletionStage<T>.sink(func: (T)->Unit) = thenAccept(Consumer(func)).toCompletableFuture()!!
+fun <T> CompletionStage<T>.sinkAsync(func: (T)->Unit) = thenAcceptAsync(Consumer(func), Minecraft.getInstance()).toCompletableFuture()!!

src/main/kotlin/mods/betterfoliage/util/Geometry.kt

@@ -0,0 +1,221 @@
+package mods.betterfoliage.util
+
+import net.minecraft.util.Direction
+import net.minecraft.util.Direction.*
+import net.minecraft.util.Direction.Axis.*
+import net.minecraft.util.Direction.AxisDirection.NEGATIVE
+import net.minecraft.util.Direction.AxisDirection.POSITIVE
+import net.minecraft.util.math.BlockPos
+
+// ================================
+// Axes and directions
+// ================================
+val axes = listOf(X, Y, Z)
+val axisDirs = listOf(POSITIVE, NEGATIVE)
+val Direction.dir: AxisDirection get() = axisDirection
+val AxisDirection.sign: String get() = when(this) { POSITIVE -> "+"; NEGATIVE -> "-" }
+val allDirections = Direction.values()
+val horizontalDirections = listOf(NORTH, SOUTH, EAST, WEST)
+val allDirOffsets = allDirections.map { Int3(it) }
+val Pair<Axis, AxisDirection>.face: Direction get() = when(this) {
+    X to POSITIVE -> EAST; X to NEGATIVE -> WEST;
+    Y to POSITIVE -> UP; Y to NEGATIVE -> DOWN;
+    Z to POSITIVE -> SOUTH; else -> NORTH;
+}
+val Direction.perpendiculars: List<Direction> get() =
+    axes.filter { it != this.axis }.cross(axisDirs).map { it.face }
+val Direction.offset: Int3 get() = allDirOffsets[ordinal]
+
+/** Old ForgeDirection rotation matrix yanked from 1.7.10 */
+val ROTATION_MATRIX: Array<IntArray> get() = arrayOf(
+    intArrayOf(0, 1, 4, 5, 3, 2, 6),
+    intArrayOf(0, 1, 5, 4, 2, 3, 6),
+    intArrayOf(5, 4, 2, 3, 0, 1, 6),
+    intArrayOf(4, 5, 2, 3, 1, 0, 6),
+    intArrayOf(2, 3, 1, 0, 4, 5, 6),
+    intArrayOf(3, 2, 0, 1, 4, 5, 6)
+)
+
+// ================================
+// Vectors
+// ================================
+operator fun Direction.times(scale: Double) =
+    Double3(directionVec.x.toDouble() * scale, directionVec.y.toDouble() * scale, directionVec.z.toDouble() * scale)
+val Direction.vec: Double3 get() = Double3(directionVec.x.toDouble(), directionVec.y.toDouble(), directionVec.z.toDouble())
+
+operator fun BlockPos.plus(other: Int3) = BlockPos(x + other.x, y + other.y, z + other.z)
+
+/** 3D vector of [Double]s. Offers both mutable operations, and immutable operations in operator notation. */
+data class Double3(var x: Double, var y: Double, var z: Double) {
+    constructor(x: Float, y: Float, z: Float) : this(x.toDouble(), y.toDouble(), z.toDouble())
+    constructor(dir: Direction) : this(dir.directionVec.x.toDouble(), dir.directionVec.y.toDouble(), dir.directionVec.z.toDouble())
+    companion object {
+        val zero: Double3 get() = Double3(0.0, 0.0, 0.0)
+        fun weight(v1: Double3, weight1: Double, v2: Double3, weight2: Double) =
+            Double3(v1.x * weight1 + v2.x * weight2, v1.y * weight1 + v2.y * weight2, v1.z * weight1 + v2.z * weight2)
+    }
+
+    // immutable operations
+    operator fun plus(other: Double3) = Double3(x + other.x, y + other.y, z + other.z)
+    operator fun unaryMinus() = Double3(-x, -y, -z)
+    operator fun minus(other: Double3) = Double3(x - other.x, y - other.y, z - other.z)
+    operator fun times(scale: Double) = Double3(x * scale, y * scale, z * scale)
+    operator fun times(other: Double3) = Double3(x * other.x, y * other.y, z * other.z)
+
+    /** Rotate this vector, and return coordinates in the unrotated frame */
+    fun rotate(rot: Rotation) = Double3(
+        rot.rotatedComponent(EAST, x, y, z),
+        rot.rotatedComponent(UP, x, y, z),
+        rot.rotatedComponent(SOUTH, x, y, z)
+    )
+
+    // mutable operations
+    fun setTo(other: Double3): Double3 { x = other.x; y = other.y; z = other.z; return this }
+    fun setTo(x: Double, y: Double, z: Double): Double3 { this.x = x; this.y = y; this.z = z; return this }
+    fun setTo(x: Float, y: Float, z: Float) = setTo(x.toDouble(), y.toDouble(), z.toDouble())
+    fun add(other: Double3): Double3 { x += other.x; y += other.y; z += other.z; return this }
+    fun add(x: Double, y: Double, z: Double): Double3 { this.x += x; this.y += y; this.z += z; return this }
+    fun sub(other: Double3): Double3 { x -= other.x; y -= other.y; z -= other.z; return this }
+    fun sub(x: Double, y: Double, z: Double): Double3 { this.x -= x; this.y -= y; this.z -= z; return this }
+    fun invert(): Double3 { x = -x; y = -y; z = -z; return this }
+    fun mul(scale: Double): Double3 { x *= scale; y *= scale; z *= scale; return this }
+    fun mul(other: Double3): Double3 { x *= other.x; y *= other.y; z *= other.z; return this }
+    fun rotateMut(rot: Rotation): Double3 {
+        val rotX = rot.rotatedComponent(EAST, x, y, z)
+        val rotY = rot.rotatedComponent(UP, x, y, z)
+        val rotZ = rot.rotatedComponent(SOUTH, x, y, z)
+        return setTo(rotX, rotY, rotZ)
+    }
+
+    // misc operations
+    infix fun dot(other: Double3) = x * other.x + y * other.y + z * other.z
+    infix fun cross(o: Double3) = Double3(y * o.z - z * o.y, z * o.x - x * o.z, x * o.y - y * o.x)
+    val length: Double get() = Math.sqrt(x * x + y * y + z * z)
+    val normalize: Double3 get() = (1.0 / length).let { Double3(x * it, y * it, z * it) }
+    val nearestCardinal: Direction get() = nearestAngle(this, allDirections.asIterable()) { it.vec }.first
+}
+
+/** 3D vector of [Int]s. Offers both mutable operations, and immutable operations in operator notation. */
+data class Int3(var x: Int, var y: Int, var z: Int) {
+    constructor(dir: Direction) : this(dir.directionVec.x, dir.directionVec.y, dir.directionVec.z)
+    constructor(offset: Pair<Int, Direction>) : this(
+        offset.first * offset.second.directionVec.x,
+        offset.first * offset.second.directionVec.y,
+        offset.first * offset.second.directionVec.z
+    )
+    companion object {
+        val zero = Int3(0, 0, 0)
+    }
+
+    // immutable operations
+    operator fun plus(other: Int3) = Int3(x + other.x, y + other.y, z + other.z)
+    operator fun plus(other: Pair<Int, Direction>) = Int3(
+        x + other.first * other.second.directionVec.x,
+        y + other.first * other.second.directionVec.y,
+        z + other.first * other.second.directionVec.z
+    )
+    operator fun unaryMinus() = Int3(-x, -y, -z)
+    operator fun minus(other: Int3) = Int3(x - other.x, y - other.y, z - other.z)
+    operator fun times(scale: Int) = Int3(x * scale, y * scale, z * scale)
+    operator fun times(other: Int3) = Int3(x * other.x, y * other.y, z * other.z)
+
+    /** Rotate this vector, and return coordinates in the unrotated frame */
+    fun rotate(rot: Rotation) = Int3(
+        rot.rotatedComponent(EAST, x, y, z),
+        rot.rotatedComponent(UP, x, y, z),
+        rot.rotatedComponent(SOUTH, x, y, z)
+    )
+
+    // mutable operations
+    fun setTo(other: Int3): Int3 { x = other.x; y = other.y; z = other.z; return this }
+    fun setTo(x: Int, y: Int, z: Int): Int3 { this.x = x; this.y = y; this.z = z; return this }
+    fun add(other: Int3): Int3 { x += other.x; y += other.y; z += other.z; return this }
+    fun sub(other: Int3): Int3 { x -= other.x; y -= other.y; z -= other.z; return this }
+    fun invert(): Int3 { x = -x; y = -y; z = -z; return this }
+    fun mul(scale: Int): Int3 { x *= scale; y *= scale; z *= scale; return this }
+    fun mul(other: Int3): Int3 { x *= other.x; y *= other.y; z *= other.z; return this }
+    fun rotateMut(rot: Rotation): Int3 {
+        val rotX = rot.rotatedComponent(EAST, x, y, z)
+        val rotY = rot.rotatedComponent(UP, x, y, z)
+        val rotZ = rot.rotatedComponent(SOUTH, x, y, z)
+        return setTo(rotX, rotY, rotZ)
+    }
+}
+
+// ================================
+// Rotation
+// ================================
+val Direction.rotations: Array<Direction> get() =
+    Array(6) { idx -> Direction.values()[ROTATION_MATRIX[ordinal][idx]] }
+fun Direction.rotate(rot: Rotation) = rot.forward[ordinal]
+fun rot(axis: Direction) = Rotation.rot90[axis.ordinal]
+
+/**
+ * Class representing an arbitrary rotation (or combination of rotations) around cardinal axes by 90 degrees.
+ * In effect, a permutation of [ForgeDirection]s.
+ */
+@Suppress("NOTHING_TO_INLINE")
+class Rotation(val forward: Array<Direction>, val reverse: Array<Direction>) {
+    operator fun plus(other: Rotation) = Rotation(
+        Array(6) { idx -> forward[other.forward[idx].ordinal] },
+        Array(6) { idx -> other.reverse[reverse[idx].ordinal] }
+    )
+    operator fun unaryMinus() = Rotation(reverse, forward)
+    operator fun times(num: Int) = when(num % 4) { 1 -> this; 2 -> this + this; 3 -> -this; else -> identity }
+
+    inline fun rotatedComponent(dir: Direction, x: Int, y: Int, z: Int) =
+        when(reverse[dir.ordinal]) { EAST -> x; WEST -> -x; UP -> y; DOWN -> -y; SOUTH -> z; NORTH -> -z; else -> 0 }
+    inline fun rotatedComponent(dir: Direction, x: Double, y: Double, z: Double) =
+        when(reverse[dir.ordinal]) { EAST -> x; WEST -> -x; UP -> y; DOWN -> -y; SOUTH -> z; NORTH -> -z; else -> 0.0 }
+
+    companion object {
+        // Forge rotation matrix is left-hand
+        val rot90 = Array(6) { idx -> Rotation(allDirections[idx].opposite.rotations, allDirections[idx].rotations) }
+        val identity = Rotation(allDirections, allDirections)
+    }
+
+}
+
+// ================================
+// Miscellaneous
+// ================================
+
+inline operator fun <reified T> Array<T>.get(face: Direction): T = get(face.ordinal)
+
+data class BoxFace(val top: Direction, val left: Direction) {
+
+    val allCorners = listOf(top to left, top to left.opposite, top.opposite to left, top.opposite to left.opposite)
+}
+val boxFaces = allDirections.map { when(it) {
+    DOWN -> BoxFace(SOUTH, WEST)
+    UP -> BoxFace(SOUTH, EAST)
+    NORTH -> BoxFace(WEST, UP)
+    SOUTH -> BoxFace(UP, WEST)
+    WEST -> BoxFace(SOUTH, UP)
+    EAST -> BoxFace(SOUTH, DOWN)
+}}.toTypedArray()
+
+/** List of all 12 box edges, represented as a [Pair] of [ForgeDirection]s */
+val boxEdges = allDirections.flatMap { face1 -> allDirections.filter { it.axis > face1.axis }.map { face1 to it } }
+
+/**
+ * Get the closest object to the specified point from a list of objects.
+ *
+ * @param[vertex] the reference point
+ * @param[objs] list of geomertric objects
+ * @param[objPos] lambda to calculate the position of an object
+ * @return [Pair] of (object, distance)
+ */
+fun <T> nearestPosition(vertex: Double3, objs: Iterable<T>, objPos: (T)-> Double3): Pair<T, Double>  =
+        objs.map { it to (objPos(it) - vertex).length }.minBy { it.second }!!
+
+/**
+ * Get the object closest in orientation to the specified vector from a list of objects.
+ *
+ * @param[vector] the reference vector (direction)
+ * @param[objs] list of geomertric objects
+ * @param[objAngle] lambda to calculate the orientation of an object
+ * @return [Pair] of (object, normalized dot product)
+ */
+fun <T> nearestAngle(vector: Double3, objs: Iterable<T>, objAngle: (T)-> Double3): Pair<T, Double> =
+        objs.map { it to objAngle(it).dot(vector) }.maxBy { it.second }!!

src/main/kotlin/mods/betterfoliage/util/Gui.kt

@@ -0,0 +1,22 @@
+@file:JvmName("Utils")
+package mods.betterfoliage.util
+
+import net.minecraft.util.text.StringTextComponent
+import net.minecraft.util.text.Style
+import net.minecraft.util.text.TextFormatting
+import net.minecraft.util.text.TextFormatting.AQUA
+import net.minecraft.util.text.TextFormatting.GRAY
+
+fun stripTooltipDefaultText(tooltip: MutableList<String>) {
+    var defaultRows = false
+    val iter = tooltip.iterator()
+    while (iter.hasNext()) {
+        if (iter.next().startsWith(AQUA.toString())) defaultRows = true
+        if (defaultRows) iter.remove()
+    }
+}
+
+fun textComponent(msg: String, color: TextFormatting = GRAY): StringTextComponent {
+    val style = Style().apply { this.color = color }
+    return StringTextComponent(msg).apply { this.style = style }
+}

src/main/kotlin/mods/betterfoliage/util/Misc.kt

@@ -0,0 +1,75 @@
+@file:Suppress("NOTHING_TO_INLINE")
+package mods.betterfoliage.util
+
+import net.minecraft.util.ResourceLocation
+import net.minecraft.util.math.BlockPos
+import net.minecraft.world.World
+import org.apache.logging.log4j.Level
+import org.apache.logging.log4j.Logger
+import java.lang.Math.*
+import kotlin.reflect.KProperty
+
+const val PI2 = 2.0 * PI
+
+/** Strip the given prefix off the start of the string, if present */
+inline fun String.stripStart(str: String, ignoreCase: Boolean = true) = if (startsWith(str, ignoreCase)) substring(str.length) else this
+inline fun String.stripEnd(str: String, ignoreCase: Boolean = true) = if (endsWith(str, ignoreCase)) substring(0, length - str.length) else this
+
+/** Strip the given prefix off the start of the resource path, if present */
+inline fun ResourceLocation.stripStart(str: String) = ResourceLocation(namespace, path.stripStart(str))
+inline fun ResourceLocation.stripEnd(str: String) = ResourceLocation(namespace, path.stripEnd(str))
+
+/**
+ * Property-level delegate backed by a [ThreadLocal].
+ *
+ * @param[init] Lambda to get initial value
+ */
+class ThreadLocalDelegate<T>(init: () -> T) {
+    var tlVal = ThreadLocal.withInitial(init)
+    operator fun getValue(thisRef: Any?, property: KProperty<*>): T = tlVal.get()
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T) { tlVal.set(value) }
+}
+
+/** Call the supplied lambda and return its result, or the given default value if an exception is thrown. */
+fun <T> tryDefault(default: T, work: ()->T) = try { work() } catch (e: Throwable) { default }
+
+/**
+ * Return this [Double] value if it lies between the two limits. If outside, return the
+ * minimum/maximum value correspondingly.
+ */
+fun Double.minmax(minVal: Double, maxVal: Double) = min(max(this, minVal), maxVal)
+
+/**
+ * Return this [Int] value if it lies between the two limits. If outside, return the
+ * minimum/maximum value correspondingly.
+ */
+fun Int.minmax(minVal: Int, maxVal: Int) = min(max(this, minVal), maxVal)
+
+fun nextPowerOf2(x: Int): Int {
+    return 1 shl (if (x == 0) 0 else 32 - Integer.numberOfLeadingZeros(x - 1))
+}
+
+/**
+ * Check if the Chunk containing the given [BlockPos] is loaded.
+ * Works for both [World] and [ChunkCache] (vanilla and OptiFine) instances.
+ */
+//fun IWorldReader.isBlockLoaded(pos: BlockPos) = when {
+//    this is World -> isBlockLoaded(pos, false)
+//    this is RenderChunkCache -> isworld.isBlockLoaded(pos, false)
+//    Refs.OptifineChunkCache.isInstance(this) -> (Refs.CCOFChunkCache.get(this) as ChunkCache).world.isBlockLoaded(pos, false)
+//    else -> false
+//}
+
+interface HasLogger {
+    val logger: Logger
+    val logName: String get() = this::class.simpleName!!
+    fun log(msg: String) = log(Level.INFO, msg)
+    fun log(level: Level, msg: String) = logger.log(level, "[$logName] $msg")
+    fun log(msg: String, e: Throwable) = log(Level.WARN, msg, e)
+    fun log(level: Level, msg: String, e: Throwable) = logger.log(level, "[$logName] $msg", e)
+}
+
+//fun textComponent(msg: String, color: Formatting = Formatting.GRAY): LiteralText {
+//    val style = Style().apply { this.color = color }
+//    return LiteralText(msg).apply { this.style = style }
+//}

src/main/kotlin/mods/betterfoliage/util/Random.kt

@@ -0,0 +1,18 @@
+package mods.betterfoliage.util
+
+import net.minecraft.util.math.BlockPos
+import java.util.Random
+
+val random = Random(System.nanoTime())
+
+fun randomB() = random.nextBoolean()
+fun randomI(min: Int = 0, max: Int = Int.MAX_VALUE) = min + random.nextInt(max - min)
+fun randomD(min: Double = 0.0, max: Double = 1.0) = random.nextDouble() * (max - min) + min
+
+fun semiRandom(x: Int, y: Int, z: Int, seed: Int): Int {
+    var value = (x * x + y * y + z * z + x * y + y * z + z * x + (seed * seed))
+    value = (3 * x * value + 5 * y * value + 7 * z * value + (11 * seed))
+    return value shr 4
+}
+
+fun BlockPos.semiRandom(seed: Int) = semiRandom(x, y, z, seed)

src/main/kotlin/mods/betterfoliage/util/Reflection.kt

@@ -0,0 +1,179 @@
+@file:JvmName("Reflection")
+package mods.betterfoliage.util
+
+import java.lang.reflect.Field
+import java.lang.reflect.Method
+import mods.betterfoliage.util.Namespace.*
+
+/** Get a Java class with the given name. */
+fun getJavaClass(name: String) = tryDefault(null) { Class.forName(name) }
+
+/** Get the field with the given name and type using reflection. */
+inline fun <reified T> Any.reflectField(field: String): T? =
+    tryDefault(null) { this.javaClass.getDeclaredField(field) }?.let {
+        it.isAccessible = true
+        it.get(this) as T
+    }
+
+/** Get the static field with the given name and type using reflection. */
+inline fun <reified T> Class<*>.reflectStaticField(field: String): T? =
+    tryDefault(null) { this.getDeclaredField(field) }?.let {
+        it.isAccessible = true
+        it.get(null) as T
+    }
+
+/**
+ * Get all nested _object_s of this _object_ with reflection.
+ *
+ * @return [Pair]s of (name, instance)
+ */
+val Any.reflectNestedObjects: List<Pair<String, Any>> get() = this.javaClass.declaredClasses.map {
+    tryDefault(null) { it.name.split("$")[1] to it.getField("INSTANCE").get(null) }
+}.filterNotNull()
+
+/**
+ * Get all fields of this instance that match (or subclass) any of the given classes.
+ *
+ * @param[types] classes to look for
+ * @return [Pair]s of (field name, instance)
+ */
+fun Any.reflectFieldsOfType(vararg types: Class<*>) = this.javaClass.declaredFields
+    .filter { field -> types.any { it.isAssignableFrom(field.type) } }
+    .map { field -> field.name to field.let { it.isAccessible = true; it.get(this) } }
+    .filterNotNull()
+
+fun <T> Any.reflectFields(type: Class<T>) = this.javaClass.declaredFields
+    .filter { field -> type.isAssignableFrom(field.type) }
+    .map { field -> field.name to field.let { it.isAccessible = true; it.get(this) as T } }
+
+fun <T> Any.reflectDelegates(type: Class<T>) = this.javaClass.declaredFields
+    .filter { field -> type.isAssignableFrom(field.type) && field.name.contains("$") }
+    .map { field -> field.name.split("$")[0] to field.let { it.isAccessible = true; it.get(this) } as T }
+
+enum class Namespace { MCP, SRG }
+
+abstract class Resolvable<T> {
+    abstract fun resolve(): T?
+    val element: T? by lazy { resolve() }
+}
+
+/** Return true if all given elements are found. */
+fun allAvailable(vararg codeElement: Resolvable<*>) = codeElement.all { it.element != null }
+
+/**
+ * Reference to a class.
+ *
+ * @param[name] MCP name of the class
+ */
+open class ClassRef<T: Any?>(val name: String) : Resolvable<Class<T>>() {
+
+    companion object {
+        val int = ClassRefPrimitive("I", Int::class.java)
+        val long = ClassRefPrimitive("J", Long::class.java)
+        val float = ClassRefPrimitive("F", Float::class.java)
+        val boolean = ClassRefPrimitive("Z", Boolean::class.java)
+        val void = ClassRefPrimitive("V", Void::class.java)
+    }
+
+    open fun asmDescriptor(namespace: Namespace) = "L${name.replace(".", "/")};"
+
+    override fun resolve() = getJavaClass(name) as Class<T>?
+
+    fun isInstance(obj: Any) = element?.isInstance(obj) ?: false
+}
+
+/**
+ * Reference to a primitive type.
+ *
+ * @param[name] ASM descriptor of this primitive type
+ * @param[clazz] class of this primitive type
+ */
+class ClassRefPrimitive<T>(name: String, val clazz: Class<T>?) : ClassRef<T>(name) {
+    override fun asmDescriptor(namespace: Namespace) = name
+    override fun resolve() = clazz
+}
+
+/**
+ * Reference to a method.
+ *
+ * @param[parentClass] reference to the class containing the method
+ * @param[mcpName] MCP name of the method
+ * @param[srgName] SRG name of the method
+ * @param[returnType] reference to the return type
+ * @param[returnType] references to the argument types
+ */
+class MethodRef<T: Any?>(val parentClass: ClassRef<*>,
+                         val mcpName: String,
+                         val srgName: String,
+                         val returnType: ClassRef<T>,
+                         vararg val argTypes: ClassRef<*>
+) : Resolvable<Method>() {
+    constructor(parentClass: ClassRef<*>, mcpName: String, returnType: ClassRef<T>, vararg argTypes: ClassRef<*>) :
+    this(parentClass, mcpName, mcpName, returnType, *argTypes)
+
+    fun name(namespace: Namespace) = when(namespace) { SRG -> srgName; MCP -> mcpName }
+    fun asmDescriptor(namespace: Namespace) = "(${argTypes.map { it.asmDescriptor(namespace) }.fold(""){ s1, s2 -> s1 + s2 } })${returnType.asmDescriptor(namespace)}"
+
+    override fun resolve(): Method? =
+        if (parentClass.element == null || argTypes.any { it.element == null }) null
+        else {
+            val args = argTypes.map { it.element!! }.toTypedArray()
+            listOf(srgName, mcpName).map { tryDefault(null) {
+                parentClass.element!!.getDeclaredMethod(it, *args)
+            }}.filterNotNull().firstOrNull()
+            ?.apply { isAccessible = true }
+        }
+
+    /** Invoke this method using reflection. */
+    operator fun invoke(receiver: Any, vararg args: Any?) = element?.invoke(receiver, *args) as T
+
+    /** Invoke this static method using reflection. */
+    fun invokeStatic(vararg args: Any) = element?.invoke(null, *args)
+}
+
+/**
+ * Reference to a field.
+ *
+ * @param[parentClass] reference to the class containing the field
+ * @param[mcpName] MCP name of the field
+ * @param[srgName] SRG name of the field
+ * @param[type] reference to the field type
+ */
+class FieldRef<T>(val parentClass: ClassRef<*>,
+                  val mcpName: String,
+                  val srgName: String,
+                  val type: ClassRef<T>
+) : Resolvable<Field>() {
+    constructor(parentClass: ClassRef<*>, mcpName: String, type: ClassRef<T>) : this(parentClass, mcpName, mcpName, type)
+
+    fun name(namespace: Namespace) = when(namespace) { SRG -> srgName; MCP -> mcpName }
+    fun asmDescriptor(namespace: Namespace) = type.asmDescriptor(namespace)
+
+    override fun resolve(): Field? =
+        if (parentClass.element == null) null
+        else {
+            listOf(srgName, mcpName).mapNotNull { tryDefault(null) {
+                parentClass.element!!.getDeclaredField(it)
+            } }.firstOrNull()
+            ?.apply{ isAccessible = true }
+        }
+
+    /** Get this field using reflection. */
+    operator fun get(receiver: Any?) = element?.get(receiver) as T
+
+    /** Get this static field using reflection. */
+    fun getStatic() = get(null)
+
+    fun set(receiver: Any?, obj: Any?) { element?.set(receiver, obj) }
+}
+
+
+fun Any.isInstance(cls: ClassRef<*>) = cls.isInstance(this)
+interface ReflectionCallable<T> {
+    operator fun invoke(vararg args: Any): T
+}
+inline operator fun <reified T> Any.get(field: FieldRef<T>) = field.get(this)
+inline operator fun <reified T> Any.set(field: FieldRef<T>, value: T) = field.set(this, value)
+inline operator fun <T> Any.get(methodRef: MethodRef<T>) = object : ReflectionCallable<T> {
+    override fun invoke(vararg args: Any) = methodRef.invoke(this@get, args)
+}

src/main/kotlin/mods/betterfoliage/util/Resources.kt

@@ -0,0 +1,26 @@
+package mods.betterfoliage.util
+
+import net.minecraft.client.Minecraft
+import net.minecraft.resources.IReloadableResourceManager
+import net.minecraft.resources.IResource
+import net.minecraft.resources.IResourceManager
+import net.minecraft.util.ResourceLocation
+
+/** Concise getter for the Minecraft resource manager. */
+val resourceManager: IReloadableResourceManager
+    get() = Minecraft.getInstance().resourceManager as IReloadableResourceManager
+
+/** Append a string to the [ResourceLocation]'s path. */
+operator fun ResourceLocation.plus(str: String) = ResourceLocation(namespace, path + str)
+
+/** Index operator to get a resource. */
+operator fun IResourceManager.get(domain: String, path: String): IResource? = get(ResourceLocation(domain, path))
+/** Index operator to get a resource. */
+operator fun IResourceManager.get(location: ResourceLocation): IResource? = tryDefault(null) { getResource(location) }
+
+/** Get the lines of a text resource. */
+fun IResource.getLines(): List<String> {
+    val result = arrayListOf<String>()
+    inputStream.bufferedReader().useLines { it.forEach { result.add(it) } }
+    return result
+}

src/main/kotlin/mods/betterfoliage/util/Sprites.kt

@@ -0,0 +1,86 @@
+package mods.betterfoliage.util
+
+import mods.betterfoliage.render.lighting.HSB
+import net.minecraft.client.Minecraft
+import net.minecraft.client.renderer.texture.AtlasTexture
+import net.minecraft.client.renderer.texture.TextureAtlasSprite
+import net.minecraft.resources.IResource
+import net.minecraft.resources.IResourceManager
+import net.minecraft.util.ResourceLocation
+import java.awt.image.BufferedImage
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import javax.imageio.ImageIO
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.sin
+
+enum class Atlas(val basePath: String, val resourceId: ResourceLocation) {
+    BLOCKS("textures", AtlasTexture.LOCATION_BLOCKS_TEXTURE),
+    PARTICLES("textures", AtlasTexture.LOCATION_PARTICLES_TEXTURE);
+
+    /** Get the fully-qualified resource name for sprites belonging to this atlas*/
+    fun wrap(resource: ResourceLocation) = ResourceLocation(resource.namespace, "$basePath/${resource.path}.png")
+
+    /** Get the short resource name for sprites belonging to this atlas*/
+    fun unwrap(resource: ResourceLocation) = resource.stripStart("$basePath/").stripEnd(".png")
+
+    /** Reference to the atlas itself */
+    val atlas: AtlasTexture get() = Minecraft.getInstance().textureManager.getTexture(resourceId) as AtlasTexture
+}
+
+inline operator fun AtlasTexture.get(res: ResourceLocation): TextureAtlasSprite? = this.getSprite(res)
+inline operator fun AtlasTexture.get(name: String): TextureAtlasSprite? = get(ResourceLocation(name))
+
+fun IResourceManager.loadSprite(id: ResourceLocation) = this.get(id)?.loadImage() ?: throw IOException("Cannot load resource $id")
+
+fun IResource.loadImage(): BufferedImage? = ImageIO.read(this.inputStream)
+
+/** Index operator to get the RGB value of a pixel. */
+operator fun BufferedImage.get(x: Int, y: Int) = this.getRGB(x, y)
+/** Index operator to set the RGB value of a pixel. */
+operator fun BufferedImage.set(x: Int, y: Int, value: Int) = this.setRGB(x, y, value)
+
+val BufferedImage.bytes: ByteArray get() =
+    ByteArrayOutputStream().let { ImageIO.write(this, "PNG", it); it.toByteArray() }
+
+/**
+ * Calculate the average color of a texture.
+ *
+ * Only non-transparent pixels are considered. Averages are taken in the HSB color space (note: Hue is a circular average),
+ * and the result transformed back to the RGB color space.
+ */
+val TextureAtlasSprite.averageColor: Int get() {
+    var numOpaque = 0
+    var sumHueX = 0.0
+    var sumHueY = 0.0
+    var sumSaturation = 0.0f
+    var sumBrightness = 0.0f
+    for (x in 0 until width)
+        for (y in 0 until height) {
+            val pixel = getPixelRGBA(0, x, y)
+            val alpha = (pixel shr 24) and 255
+            val hsb = HSB.fromColor(pixel)
+            if (alpha == 255) {
+                numOpaque++
+                sumHueX += cos((hsb.hue.toDouble() - 0.5) * PI2)
+                sumHueY += sin((hsb.hue.toDouble() - 0.5) * PI2)
+                sumSaturation += hsb.saturation
+                sumBrightness += hsb.brightness
+            }
+        }
+
+    // circular average - transform sum vector to polar angle
+    val avgHue = (atan2(sumHueY, sumHueX) / PI2 + 0.5).toFloat()
+    return HSB(avgHue, sumSaturation / numOpaque.toFloat(), sumBrightness / numOpaque.toFloat()).asColor
+}
+
+/** Weighted blend of 2 packed RGB colors */
+fun blendRGB(rgb1: Int, rgb2: Int, weight1: Int, weight2: Int): Int {
+    val r = (((rgb1 shr 16) and 255) * weight1 + ((rgb2 shr 16) and 255) * weight2) / (weight1 + weight2)
+    val g = (((rgb1 shr 8) and 255) * weight1 + ((rgb2 shr 8) and 255) * weight2) / (weight1 + weight2)
+    val b = ((rgb1 and 255) * weight1 + (rgb2 and 255) * weight2) / (weight1 + weight2)
+    val a = (rgb1 shr 24) and 255
+    val result = ((a shl 24) or (r shl 16) or (g shl 8) or b)
+    return result
+}