first Kotlin version

src/main/kotlin/mods/betterfoliage/client/texture/GrassRegistry.kt

@@ -0,0 +1,69 @@
+package mods.betterfoliage.client.texture
+
+import cpw.mods.fml.common.eventhandler.SubscribeEvent
+import cpw.mods.fml.relauncher.Side
+import cpw.mods.fml.relauncher.SideOnly
+import mods.betterfoliage.client.Client
+import mods.betterfoliage.client.config.Config
+import mods.octarinecore.client.render.HSB
+import mods.octarinecore.client.resource.averageColor
+import net.minecraft.block.Block
+import net.minecraft.client.renderer.texture.TextureAtlasSprite
+import net.minecraft.client.renderer.texture.TextureMap
+import net.minecraft.util.IIcon
+import net.minecraftforge.client.event.TextureStitchEvent
+import net.minecraftforge.common.MinecraftForge
+import org.apache.logging.log4j.Level.DEBUG
+import org.apache.logging.log4j.Level.INFO
+
+const val defaultGrassColor = 0
+
+/** Rendering-related information for a grass block. */
+class GrassInfo(
+    /** Top texture of the grass block. */
+    val grassTopTexture: TextureAtlasSprite,
+
+    /**
+     * Color to use for Short Grass rendering instead of the biome color.
+     *
+     * Value is null if the texture is mostly grey (the saturation of its average color is under a configurable limit),
+     * the average color of the texture (significantly brightened) otherwise.
+     */
+    val overrideColor: Int?
+)
+
+/** Collects and manages rendering-related information for grass blocks. */
+@SideOnly(Side.CLIENT)
+object GrassRegistry {
+
+    val grass: MutableMap<IIcon, GrassInfo> = hashMapOf()
+
+    init {
+        MinecraftForge.EVENT_BUS.register(this)
+    }
+
+    @SubscribeEvent
+    fun handleTextureReload(event: TextureStitchEvent.Pre) {
+        if (event.map.textureType != 0) return
+        grass.clear()
+        Client.log(INFO, "Inspecting grass textures")
+
+        Block.blockRegistry.forEach { block ->
+            if (Config.blocks.grass.matchesClass(block as Block)) {
+                block.registerBlockIcons { location ->
+                    val original = event.map.getTextureExtry(location)
+                    Client.log(DEBUG, "Found grass texture: $location")
+                    registerGrass(event.map, original)
+                    return@registerBlockIcons original
+                }
+            }
+        }
+    }
+
+    fun registerGrass(atlas: TextureMap, icon: TextureAtlasSprite) {
+        val hsb = HSB.fromColor(icon.averageColor ?: defaultGrassColor)
+        val overrideColor = if (hsb.saturation > Config.shortGrass.saturationThreshold) hsb.copy(brightness = 0.8f).asColor else null
+        grass.put(icon, GrassInfo(icon, overrideColor))
+    }
+
+}