[WIP] start port to 1.15.2

src/main/kotlin/mods/betterfoliage/model/SpriteSets.kt

@@ -0,0 +1,75 @@
+package mods.betterfoliage.model
+
+import mods.betterfoliage.util.Atlas
+import mods.betterfoliage.util.get
+import net.fabricmc.fabric.api.event.client.ClientSpriteRegistryCallback
+import net.minecraft.client.MinecraftClient
+import net.minecraft.client.texture.MissingSprite
+import net.minecraft.client.texture.Sprite
+import net.minecraft.client.texture.SpriteAtlasTexture
+import net.minecraft.util.Identifier
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+interface SpriteSet {
+    val num: Int
+    operator fun get(idx: Int): Sprite
+}
+
+class FixedSpriteSet(val sprites: List<Sprite>) : SpriteSet {
+    override val num = sprites.size
+    override fun get(idx: Int) = sprites[idx % num]
+
+    constructor(atlas: Atlas, ids: List<Identifier>) : this(
+        ids.mapNotNull { atlas.atlas[it] }.let { sprites ->
+            if (sprites.isNotEmpty()) sprites else listOf(atlas.atlas[MissingSprite.getMissingSpriteId()]!!)
+        }
+    )
+}
+
+class SpriteDelegate(val atlas: Atlas, val idFunc: ()->Identifier) : ReadOnlyProperty<Any, Sprite>, ClientSpriteRegistryCallback {
+    private var id: Identifier? = null
+    private var value: Sprite? = null
+
+    init { ClientSpriteRegistryCallback.event(atlas.resourceId).register(this) }
+
+    override fun registerSprites(atlasTexture: SpriteAtlasTexture, registry: ClientSpriteRegistryCallback.Registry) {
+        id = idFunc(); value = null
+        registry.register(id)
+    }
+
+    override fun getValue(thisRef: Any, property: KProperty<*>): Sprite {
+        value?.let { return it }
+        synchronized(this) {
+            value?.let { return it }
+            atlas.atlas[id!!]!!.let { value = it; return it }
+        }
+    }
+}
+
+
+class SpriteSetDelegate(
+    val atlas: Atlas,
+    val idRegister: (Identifier)->Identifier = { it },
+    val idFunc: (Int)->Identifier
+) : ReadOnlyProperty<Any, SpriteSet>, ClientSpriteRegistryCallback {
+    private var idList: List<Identifier> = emptyList()
+    private var spriteSet: SpriteSet? = null
+    init { ClientSpriteRegistryCallback.event(atlas.resourceId).register(this) }
+
+    override fun registerSprites(atlasTexture: SpriteAtlasTexture, registry: ClientSpriteRegistryCallback.Registry) {
+        spriteSet = null
+        val manager = MinecraftClient.getInstance().resourceManager
+        idList = (0 until 16).map(idFunc).filter { manager.containsResource(atlas.wrap(it)) }.map(idRegister)
+        idList.forEach { registry.register(it) }
+    }
+
+    override fun getValue(thisRef: Any, property: KProperty<*>): SpriteSet {
+        spriteSet?.let { return it }
+        synchronized(this) {
+            spriteSet?.let { return it }
+            spriteSet = FixedSpriteSet(atlas, idList)
+            return spriteSet!!
+        }
+    }
+}