[WIP] start 1.15 port

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

src/main/kotlin/mods/betterfoliage/chunk/Overlay.kt

@@ -0,0 +1,125 @@
+package mods.betterfoliage.chunk
+
+import mods.octarinecore.ChunkCacheOF
+import mods.betterfoliage.render.old.BlockCtx
+import mods.betterfoliage.util.get
+import mods.betterfoliage.util.isInstance
+import net.minecraft.client.renderer.chunk.ChunkRenderCache
+import net.minecraft.client.world.ClientWorld
+import net.minecraft.util.math.BlockPos
+import net.minecraft.util.math.ChunkPos
+import net.minecraft.world.ILightReader
+import net.minecraft.world.IWorldReader
+import net.minecraft.world.dimension.DimensionType
+import net.minecraftforge.common.MinecraftForge
+import net.minecraftforge.event.world.ChunkEvent
+import net.minecraftforge.event.world.WorldEvent
+import net.minecraftforge.eventbus.api.SubscribeEvent
+import java.util.*
+import kotlin.collections.List
+import kotlin.collections.MutableMap
+import kotlin.collections.associateWith
+import kotlin.collections.forEach
+import kotlin.collections.mutableListOf
+import kotlin.collections.mutableMapOf
+import kotlin.collections.set
+
+val ILightReader.dimType: DimensionType get() = when {
+    this is IWorldReader -> dimension.type
+    this is ChunkRenderCache -> world.dimension.type
+    this.isInstance(ChunkCacheOF) -> this[ChunkCacheOF.chunkCache].world.dimension.type
+    else -> throw IllegalArgumentException("DimensionType of world with class ${this::class.qualifiedName} cannot be determined!")
+}
+
+/**
+ * Represents some form of arbitrary non-persistent data that can be calculated and cached for each block position
+ */
+interface ChunkOverlayLayer<T> {
+    fun calculate(ctx: BlockCtx): T
+    fun onBlockUpdate(world: ILightReader, pos: BlockPos)
+}
+
+/**
+ * Query, lazy calculation and lifecycle management of multiple layers of chunk overlay data.
+ */
+object ChunkOverlayManager {
+
+    var tempCounter = 0
+
+    init {
+        MinecraftForge.EVENT_BUS.register(this)
+    }
+
+    val chunkData = IdentityHashMap<DimensionType, MutableMap<ChunkPos, ChunkOverlayData>>()
+    val layers = mutableListOf<ChunkOverlayLayer<*>>()
+
+    /**
+     * Get the overlay data for a given layer and position
+     *
+     * @param layer Overlay layer to query
+     * @param reader World to use if calculation of overlay value is necessary
+     * @param pos Block position
+     */
+    fun <T> get(layer: ChunkOverlayLayer<T>, ctx: BlockCtx): T? {
+        val data = chunkData[ctx.world.dimType]?.get(ChunkPos(ctx.pos)) ?: return null
+        data.get(layer, ctx.pos).let { value ->
+            if (value !== ChunkOverlayData.UNCALCULATED) return value
+            val newValue = layer.calculate(ctx)
+            data.set(layer, ctx.pos, newValue)
+            return newValue
+        }
+    }
+
+    /**
+     * Clear the overlay data for a given layer and position
+     *
+     * @param layer Overlay layer to clear
+     * @param pos Block position
+     */
+    fun <T> clear(dimension: DimensionType, layer: ChunkOverlayLayer<T>, pos: BlockPos) {
+        chunkData[dimension]?.get(ChunkPos(pos))?.clear(layer, pos)
+    }
+
+    fun onBlockChange(world: ClientWorld, pos: BlockPos) {
+        if (chunkData[world.dimType]?.containsKey(ChunkPos(pos)) == true) {
+            layers.forEach { layer -> layer.onBlockUpdate(world, pos) }
+        }
+    }
+
+    @SubscribeEvent
+    fun handleLoadWorld(event: WorldEvent.Load) = (event.world as? ClientWorld)?.let { world ->
+        chunkData[world.dimType] = mutableMapOf()
+    }
+
+    @SubscribeEvent
+    fun handleUnloadWorld(event: WorldEvent.Unload) = (event.world as? ClientWorld)?.let { world ->
+        chunkData.remove(world.dimType)
+    }
+
+    @SubscribeEvent
+    fun handleLoadChunk(event: ChunkEvent.Load) = (event.world as? ClientWorld)?.let { world ->
+        chunkData[world.dimType]?.let { chunks ->
+            // check for existence first because Optifine fires a TON of these
+            if (event.chunk.pos !in chunks.keys) chunks[event.chunk.pos] = ChunkOverlayData(layers)
+        }
+    }
+
+    @SubscribeEvent
+    fun handleUnloadChunk(event: ChunkEvent.Unload) = (event.world as? ClientWorld)?.let { world ->
+        chunkData[world.dimType]?.remove(event.chunk.pos)
+    }
+}
+
+class ChunkOverlayData(layers: List<ChunkOverlayLayer<*>>) {
+    val BlockPos.isValid: Boolean get() = y in validYRange
+    val rawData = layers.associateWith { emptyOverlay() }
+    fun <T> get(layer: ChunkOverlayLayer<T>, pos: BlockPos): T? = if (pos.isValid) rawData[layer]?.get(pos.x and 15)?.get(pos.z and 15)?.get(pos.y) as T? else null
+    fun <T> set(layer: ChunkOverlayLayer<T>, pos: BlockPos, data: T) = if (pos.isValid) rawData[layer]?.get(pos.x and 15)?.get(pos.z and 15)?.set(pos.y, data) else null
+    fun <T> clear(layer: ChunkOverlayLayer<T>, pos: BlockPos) = if (pos.isValid) rawData[layer]?.get(pos.x and 15)?.get(pos.z and 15)?.set(pos.y, UNCALCULATED) else null
+
+    companion object {
+        val UNCALCULATED = object {}
+        fun emptyOverlay() = Array(16) { Array(16) { Array<Any?>(256) { UNCALCULATED }}}
+        val validYRange = 0 until 256
+    }
+}