[WIP] Falling leaves working

+ more cleanup
+ fix double-tinted leaves

src/main/kotlin/mods/betterfoliage/render/EntityFallingLeavesFX.kt

@@ -1,13 +1,25 @@
 package mods.betterfoliage.render
 
+import com.mojang.blaze3d.vertex.IVertexBuilder
+import mods.betterfoliage.BetterFoliage
 import mods.betterfoliage.config.Config
 import mods.betterfoliage.render.old.AbstractEntityFX
 import mods.betterfoliage.model.HSB
+import mods.betterfoliage.model.getActualRenderModel
+import mods.betterfoliage.render.particle.AbstractParticle
+import mods.betterfoliage.texture.LeafParticleKey
+import mods.betterfoliage.texture.LeafParticleRegistry
 import mods.betterfoliage.util.Double3
 import mods.betterfoliage.util.PI2
+import mods.betterfoliage.util.get
 import mods.betterfoliage.util.minmax
+import mods.betterfoliage.util.randomB
 import mods.betterfoliage.util.randomD
+import mods.betterfoliage.util.randomF
+import mods.betterfoliage.util.randomI
 import net.minecraft.client.Minecraft
+import net.minecraft.client.particle.IParticleRenderType
+import net.minecraft.client.renderer.ActiveRenderInfo
 import net.minecraft.client.renderer.BufferBuilder
 import net.minecraft.util.math.BlockPos
 import net.minecraft.util.math.MathHelper
@@ -23,116 +35,3 @@ import kotlin.math.sin
 
 const val rotationFactor = PI2.toFloat() / 64.0f
 
-class EntityFallingLeavesFX(
-    world: World, pos: BlockPos
-) : AbstractEntityFX(
-    world, pos.x.toDouble() + 0.5, pos.y.toDouble(), pos.z.toDouble() + 0.5
-) {
-
-    companion object {
-        @JvmStatic val biomeBrightnessMultiplier = 0.5f
-    }
-
-    var particleRot = rand.nextInt(64)
-    var rotPositive = true
-    val isMirrored = (rand.nextInt() and 1) == 1
-    var wasCollided = false
-
-    init {
-        maxAge = MathHelper.floor(randomD(0.6, 1.0) * Config.fallingLeaves.lifetime * 20.0)
-        motionY = -Config.fallingLeaves.speed
-
-        particleScale = Config.fallingLeaves.size.toFloat() * 0.1f
-
-        val state = world.getBlockState(pos)
-//        val leafInfo = LeafRegistry[state, world, pos]
-        val blockColor = Minecraft.getInstance().blockColors.getColor(state, world, pos, 0)
-//        if (leafInfo != null) {
-//            sprite = leafInfo.particleTextures[rand.nextInt(1024)]
-//            calculateParticleColor(leafInfo.averageColor, blockColor)
-//        } else {
-//            sprite = LeafParticleRegistry["default"][rand.nextInt(1024)]
-//            setColor(blockColor)
-//        }
-    }
-
-    override val isValid: Boolean get() = (sprite != null)
-
-    override fun update() {
-        if (rand.nextFloat() > 0.95f) rotPositive = !rotPositive
-        if (age > maxAge - 20) particleAlpha = 0.05f * (maxAge - age)
-
-        if (onGround || wasCollided) {
-            velocity.setTo(0.0, 0.0, 0.0)
-            if (!wasCollided) {
-                age = age.coerceAtLeast(maxAge - 20)
-                wasCollided = true
-            }
-        } else {
-            velocity.setTo(cos[particleRot], 0.0, sin[particleRot]).mul(Config.fallingLeaves.perturb)
-                    .add(LeafWindTracker.current).add(0.0, -1.0, 0.0).mul(Config.fallingLeaves.speed)
-            particleRot = (particleRot + (if (rotPositive) 1 else -1)) and 63
-            particleAngle = rotationFactor * particleRot.toFloat()
-        }
-    }
-
-    override fun render(worldRenderer: BufferBuilder, partialTickTime: Float) {
-//        if (Config.fallingLeaves.opacityHack) GL11.glDepthMask(true)
-//        renderParticleQuad(worldRenderer, partialTickTime, rotation = particleRot, isMirrored = isMirrored)
-    }
-
-    fun calculateParticleColor(textureAvgColor: Int, blockColor: Int) {
-        val texture = HSB.fromColor(textureAvgColor)
-        val block = HSB.fromColor(blockColor)
-
-        val weightTex = texture.saturation / (texture.saturation + block.saturation)
-        val weightBlock = 1.0f - weightTex
-
-        // avoid circular average for hue for performance reasons
-        // one of the color components should dominate anyway
-        val particle = HSB(
-            weightTex * texture.hue + weightBlock * block.hue,
-            weightTex * texture.saturation + weightBlock * block.saturation,
-            weightTex * texture.brightness + weightBlock * block.brightness * biomeBrightnessMultiplier
-        )
-        setColor(particle.asColor)
-    }
-}
-
-object LeafWindTracker {
-    var random = Random()
-    val target = Double3.zero
-    val current = Double3.zero
-    var nextChange: Long = 0
-
-    init {
-        MinecraftForge.EVENT_BUS.register(this)
-    }
-
-    fun changeWind(world: World) {
-        nextChange = world.worldInfo.gameTime + 120 + random.nextInt(80)
-        val direction = PI2 * random.nextDouble()
-        val speed = abs(random.nextGaussian()) * Config.fallingLeaves.windStrength +
-            (if (!world.isRaining) 0.0 else abs(random.nextGaussian()) * Config.fallingLeaves.stormStrength)
-        target.setTo(cos(direction) * speed, 0.0, sin(direction) * speed)
-    }
-
-    @SubscribeEvent
-    fun handleWorldTick(event: TickEvent.ClientTickEvent) {
-        if (event.phase == TickEvent.Phase.START) Minecraft.getInstance().world?.let { world ->
-            // change target wind speed
-            if (world.worldInfo.dayTime >= nextChange) changeWind(world)
-
-            // change current wind speed
-            val changeRate = if (world.isRaining) 0.015 else 0.005
-            current.add(
-                (target.x - current.x).minmax(-changeRate, changeRate),
-                0.0,
-                (target.z - current.z).minmax(-changeRate, changeRate)
-            )
-        }
-    }
-
-    @SubscribeEvent
-    fun handleWorldLoad(event: WorldEvent.Load) { if (event.world.isRemote) changeWind(event.world.world) }
-}

src/main/kotlin/mods/betterfoliage/render/block/vanilla/Grass.kt

@@ -6,25 +6,25 @@ import mods.betterfoliage.config.BlockConfig
 import mods.betterfoliage.config.Config
 import mods.betterfoliage.config.ConfigurableBlockMatcher
 import mods.betterfoliage.config.ModelTextureList
-import mods.betterfoliage.model.SpecialRenderModel
-import mods.betterfoliage.render.lighting.LightingPreferredFace
 import mods.betterfoliage.model.Color
 import mods.betterfoliage.model.HalfBakedSpecialWrapper
 import mods.betterfoliage.model.HalfBakedWrapperKey
+import mods.betterfoliage.model.SpecialRenderModel
+import mods.betterfoliage.model.SpriteSetDelegate
+import mods.betterfoliage.model.buildTufts
+import mods.betterfoliage.model.fullCubeTextured
+import mods.betterfoliage.model.tuftModelSet
+import mods.betterfoliage.model.tuftShapeSet
+import mods.betterfoliage.render.lighting.LightingPreferredFace
 import mods.betterfoliage.render.pipeline.RenderCtxBase
 import mods.betterfoliage.render.pipeline.RenderCtxVanilla
 import mods.betterfoliage.resource.discovery.BakeWrapperManager
 import mods.betterfoliage.resource.discovery.ConfigurableModelDiscovery
 import mods.betterfoliage.resource.discovery.ModelBakingKey
-import mods.betterfoliage.model.SpriteSetDelegate
-import mods.betterfoliage.model.buildTufts
-import mods.betterfoliage.model.fullCubeTextured
-import mods.betterfoliage.model.fullCubeTinted
-import mods.betterfoliage.model.tuftModelSet
-import mods.betterfoliage.model.tuftShapeSet
 import mods.betterfoliage.util.Atlas
 import mods.betterfoliage.util.LazyInvalidatable
 import mods.betterfoliage.util.LazyMapInvalidatable
+import mods.betterfoliage.util.averageColor
 import mods.betterfoliage.util.get
 import mods.betterfoliage.util.isSnow
 import mods.betterfoliage.util.randomI
@@ -44,7 +44,7 @@ object StandardGrassDiscovery : ConfigurableModelDiscovery() {
         sprites: MutableSet<ResourceLocation>,
         replacements: MutableMap<ResourceLocation, ModelBakingKey>
     ): Boolean {
-        replacements[location] = StandardGrassKey(textureMatch[0])
+        replacements[location] = StandardGrassKey(textureMatch[0], null)
         Client.blockTypes.grass.add(state)
 //        RenderTypeLookup.setRenderLayer(state.block, RenderType.getCutout())
         return true
@@ -52,11 +52,17 @@ object StandardGrassDiscovery : ConfigurableModelDiscovery() {
 }
 
 data class StandardGrassKey(
-    val grassLocation: ResourceLocation
+    val grassLocation: ResourceLocation,
+    val overrideColor: Color?
 ) : HalfBakedWrapperKey() {
+    val tintIndex: Int get() = if (overrideColor == null) 0 else -1
+
     override fun replace(wrapped: SpecialRenderModel): SpecialRenderModel {
-        Atlas.BLOCKS[grassLocation].logColorOverride(detailLogger, Config.shortGrass.saturationThreshold)
-        return StandardGrassModel(wrapped, this)
+        val grassSpriteColor = Atlas.BLOCKS[grassLocation].averageColor.let { hsb ->
+            logColorOverride(BetterFoliageMod.detailLogger(this), Config.shortGrass.saturationThreshold, hsb)
+            hsb.colorOverride(Config.shortGrass.saturationThreshold)
+        }
+        return StandardGrassModel(wrapped, this.copy(overrideColor = grassSpriteColor))
     }
 }
 
@@ -101,17 +107,16 @@ class StandardGrassModel(
             Config.shortGrass.let { tuftShapeSet(it.size, it.heightMin, it.heightMax, it.hOffset) }
         }
         val grassTuftMeshesNormal = LazyMapInvalidatable(BakeWrapperManager) { key: StandardGrassKey ->
-            val overrideColor = Atlas.BLOCKS[key.grassLocation].getColorOverride(Config.shortGrass.saturationThreshold)
-            tuftModelSet(grassTuftShapes, overrideColor) { idx -> grassTuftSprites[randomI()] }.buildTufts()
+            tuftModelSet(grassTuftShapes, key.overrideColor) { idx -> grassTuftSprites[randomI()] }.buildTufts()
         }
         val grassTuftMeshesSnowed = LazyMapInvalidatable(BakeWrapperManager) { key: StandardGrassKey ->
             tuftModelSet(grassTuftShapes, Color.white) { idx -> grassTuftSprites[randomI()] }.buildTufts()
         }
         val grassFullBlockMeshes = LazyMapInvalidatable(BakeWrapperManager) { key: StandardGrassKey ->
-            Array(64) { fullCubeTinted(key.grassLocation, Config.shortGrass.saturationThreshold) }
+            Array(64) { fullCubeTextured(key.grassLocation, key.tintIndex) }
         }
         val snowFullBlockMeshes by LazyInvalidatable(BakeWrapperManager) {
-            Array(64) { fullCubeTextured(ResourceLocation("block/snow"), Color.white) }
+            Array(64) { fullCubeTextured(ResourceLocation("block/snow"), -1) }
         }
     }
 }

src/main/kotlin/mods/betterfoliage/render/block/vanilla/Leaf.kt

@@ -6,30 +6,32 @@ import mods.betterfoliage.config.BlockConfig
 import mods.betterfoliage.config.Config
 import mods.betterfoliage.config.ConfigurableBlockMatcher
 import mods.betterfoliage.config.ModelTextureList
-import mods.betterfoliage.model.SpecialRenderModel
-import mods.betterfoliage.render.lighting.RoundLeafLighting
 import mods.betterfoliage.model.Color
+import mods.betterfoliage.model.HSB
 import mods.betterfoliage.model.HalfBakedSpecialWrapper
 import mods.betterfoliage.model.HalfBakedWrapperKey
+import mods.betterfoliage.model.SpecialRenderModel
+import mods.betterfoliage.model.SpriteSetDelegate
+import mods.betterfoliage.model.crossModelsRaw
+import mods.betterfoliage.model.crossModelsTextured
+import mods.betterfoliage.render.lighting.RoundLeafLighting
 import mods.betterfoliage.render.pipeline.RenderCtxBase
 import mods.betterfoliage.render.pipeline.RenderCtxVanilla
 import mods.betterfoliage.resource.discovery.BakeWrapperManager
 import mods.betterfoliage.resource.discovery.ConfigurableModelDiscovery
 import mods.betterfoliage.resource.discovery.ModelBakingKey
 import mods.betterfoliage.resource.generated.GeneratedLeaf
-import mods.betterfoliage.model.SpriteSetDelegate
-import mods.betterfoliage.model.crossModelsRaw
-import mods.betterfoliage.model.crossModelsTextured
-import mods.betterfoliage.model.crossModelsTinted
+import mods.betterfoliage.texture.LeafBlockModel
+import mods.betterfoliage.texture.LeafParticleKey
 import mods.betterfoliage.texture.LeafParticleRegistry
 import mods.betterfoliage.util.Atlas
 import mods.betterfoliage.util.LazyMapInvalidatable
 import mods.betterfoliage.util.averageColor
 import mods.betterfoliage.util.isSnow
 import net.minecraft.block.BlockState
-import net.minecraft.client.renderer.texture.TextureAtlasSprite
 import net.minecraft.util.Direction.UP
 import net.minecraft.util.ResourceLocation
+import org.apache.logging.log4j.Level.DEBUG
 import org.apache.logging.log4j.Level.INFO
 import org.apache.logging.log4j.Logger
 
@@ -50,13 +52,12 @@ object StandardLeafDiscovery : ConfigurableModelDiscovery() {
             .apply { sprites.add(this) }
 
         detailLogger.log(INFO, "     particle $leafType")
-        replacements[location] = StandardLeafKey(generated, leafType)
+        replacements[location] = StandardLeafKey(generated, leafType, null)
         return true
     }
 }
 
-fun TextureAtlasSprite.logColorOverride(logger: Logger, threshold: Double) {
-    val hsb = averageColor
+fun logColorOverride(logger: Logger, threshold: Double, hsb: HSB) {
     return if (hsb.saturation >= threshold) {
         logger.log(INFO, "         brightness ${hsb.brightness}")
         logger.log(INFO, "         saturation ${hsb.saturation} >= ${threshold}, will use texture color")
@@ -65,24 +66,30 @@ fun TextureAtlasSprite.logColorOverride(logger: Logger, threshold: Double) {
     }
 }
 
-fun TextureAtlasSprite.getColorOverride(threshold: Double) = averageColor.let {
-    if (it.saturation < threshold) null else it.copy(brightness = (it.brightness * 2.0f).coerceAtMost(0.9f))
-}?.asColor?.let { Color(it) }
+fun HSB.colorOverride(threshold: Double) =
+    if (saturation < threshold) null else copy(brightness = (brightness * 2.0f).coerceAtMost(0.9f)).asColor.let { Color(it) }
 
 data class StandardLeafKey(
     val roundLeafTexture: ResourceLocation,
-    val leafType: String
-) : HalfBakedWrapperKey() {
+    override val leafType: String,
+    override val overrideColor: Color?
+) : HalfBakedWrapperKey(), LeafParticleKey {
+    val tintIndex: Int get() = if (overrideColor == null) 0 else -1
+
     override fun replace(wrapped: SpecialRenderModel): SpecialRenderModel {
-        Atlas.BLOCKS[roundLeafTexture].logColorOverride(BetterFoliageMod.detailLogger(this), 0.1)
-        return StandardLeafModel(wrapped, this)
+        val leafSpriteColor = Atlas.BLOCKS[roundLeafTexture].averageColor.let { hsb ->
+            logColorOverride(BetterFoliageMod.detailLogger(this), Config.leaves.saturationThreshold, hsb)
+            hsb.colorOverride(Config.leaves.saturationThreshold)
+        }
+        detailLogger.log(DEBUG, "roundLeaf=$roundLeafTexture overrideColor=$leafSpriteColor")
+        return StandardLeafModel(wrapped, this.copy(overrideColor = leafSpriteColor))
     }
 }
 
 class StandardLeafModel(
     model: SpecialRenderModel,
-    key: StandardLeafKey
-) : HalfBakedSpecialWrapper(model) {
+    override val key: StandardLeafKey
+) : HalfBakedSpecialWrapper(model), LeafBlockModel {
     val leafNormal by leafModelsNormal.delegate(key)
     val leafSnowed by leafModelsSnowed.delegate(key)
 
@@ -103,10 +110,10 @@ class StandardLeafModel(
             Config.leaves.let { crossModelsRaw(64, it.size, it.hOffset, it.vOffset) }
         }
         val leafModelsNormal = LazyMapInvalidatable(BakeWrapperManager) { key: StandardLeafKey ->
-            crossModelsTinted(leafModelsBase[key], Config.shortGrass.saturationThreshold) { key.roundLeafTexture }
+            crossModelsTextured(leafModelsBase[key], key.tintIndex, true) { key.roundLeafTexture }
         }
         val leafModelsSnowed = LazyMapInvalidatable(BakeWrapperManager) { key: StandardLeafKey ->
-            crossModelsTextured(leafModelsBase[key], Color.white, false) { leafSpritesSnowed[it].name }
+            crossModelsTextured(leafModelsBase[key], -1, false) { leafSpritesSnowed[it].name }
         }
     }
 }

src/main/kotlin/mods/betterfoliage/render/particle/AbstractParticle.kt

@@ -0,0 +1,101 @@
+package mods.betterfoliage.render.particle
+
+import com.mojang.blaze3d.vertex.IVertexBuilder
+import mods.betterfoliage.util.Double3
+import net.minecraft.client.Minecraft
+import net.minecraft.client.particle.SpriteTexturedParticle
+import net.minecraft.client.renderer.ActiveRenderInfo
+import net.minecraft.client.renderer.Vector3f
+import net.minecraft.client.renderer.texture.TextureAtlasSprite
+import net.minecraft.util.math.MathHelper
+import net.minecraft.world.World
+
+abstract class AbstractParticle(world: World, x: Double, y: Double, z: Double) : SpriteTexturedParticle(world, x, y, z) {
+
+    companion object {
+//        @JvmStatic val sin = Array(64) { idx -> Math.sin(PI2 / 64.0 * idx) }
+//        @JvmStatic val cos = Array(64) { idx -> Math.cos(PI2 / 64.0 * idx) }
+    }
+
+    val billboardRot = Pair(Double3.zero, Double3.zero)
+    val currentPos = Double3.zero
+    val prevPos = Double3.zero
+    val velocity = Double3.zero
+
+    override fun tick() {
+        super.tick()
+        currentPos.setTo(posX, posY, posZ)
+        prevPos.setTo(prevPosX, prevPosY, prevPosZ)
+        velocity.setTo(motionX, motionY, motionZ)
+        update()
+        posX = currentPos.x; posY = currentPos.y; posZ = currentPos.z;
+        motionX = velocity.x; motionY = velocity.y; motionZ = velocity.z;
+    }
+
+    /** Update particle on world tick. */
+    abstract fun update()
+
+    /** True if the particle is renderable. */
+    abstract val isValid: Boolean
+
+    /** Add the particle to the effect renderer if it is valid. */
+    fun addIfValid() { if (isValid) Minecraft.getInstance().particles.addEffect(this) }
+
+    override fun renderParticle(vertexBuilder: IVertexBuilder, camera: ActiveRenderInfo, tickDelta: Float) {
+        super.renderParticle(vertexBuilder, camera, tickDelta)
+    }
+
+    /**
+     * Render a particle quad.
+     *
+     * @param[tessellator] the [Tessellator] instance to use
+     * @param[tickDelta] partial tick time
+     * @param[currentPos] render position
+     * @param[prevPos] previous tick position for interpolation
+     * @param[size] particle size
+     * @param[currentAngle] viewpoint-dependent particle rotation (64 steps)
+     * @param[sprite] particle texture
+     * @param[isMirrored] mirror particle texture along V-axis
+     * @param[alpha] aplha blending
+     */
+    fun renderParticleQuad(vertexConsumer: IVertexBuilder,
+                           camera: ActiveRenderInfo,
+                           tickDelta: Float,
+                           currentPos: Double3 = this.currentPos,
+                           prevPos: Double3 = this.prevPos,
+                           size: Double = particleScale.toDouble(),
+                           currentAngle: Float = this.particleAngle,
+                           prevAngle: Float = this.prevParticleAngle,
+                           sprite: TextureAtlasSprite = this.sprite,
+                           alpha: Float = this.particleAlpha) {
+
+        val center = Double3.lerp(tickDelta.toDouble(), prevPos, currentPos)
+        val angle = MathHelper.lerp(tickDelta, prevAngle, currentAngle)
+        val rotation = camera.rotation.copy().apply { multiply(Vector3f.ZP.rotation(angle)) }
+        val lightmapCoord = getBrightnessForRender(tickDelta)
+
+        val coords = arrayOf(
+            Double3(-1.0, -1.0, 0.0),
+            Double3(-1.0, 1.0, 0.0),
+            Double3(1.0, 1.0, 0.0),
+            Double3(1.0, -1.0, 0.0)
+        ).map { it.rotate(rotation).mul(size).add(center).sub(camera.projectedView.x, camera.projectedView.y, camera.projectedView.z) }
+
+        fun renderVertex(vertex: Double3, u: Float, v: Float) = vertexConsumer
+            .pos(vertex.x, vertex.y, vertex.z).tex(u, v)
+            .color(particleRed, particleGreen, particleBlue, alpha).lightmap(lightmapCoord)
+            .endVertex()
+
+        renderVertex(coords[0], sprite.maxU, sprite.maxV)
+        renderVertex(coords[1], sprite.maxU, sprite.minV)
+        renderVertex(coords[2], sprite.minU, sprite.minV)
+        renderVertex(coords[3], sprite.minU, sprite.maxV)
+    }
+
+    fun setColor(color: Int) {
+        particleBlue = (color and 255) / 256.0f
+        particleGreen = ((color shr 8) and 255) / 256.0f
+        particleRed = ((color shr 16) and 255) / 256.0f
+    }
+}
+

src/main/kotlin/mods/betterfoliage/render/particle/FallingLeaves.kt

@@ -0,0 +1,132 @@
+package mods.betterfoliage.render.particle
+
+import mods.betterfoliage.config.Config
+import mods.betterfoliage.model.HSB
+import mods.betterfoliage.texture.LeafParticleKey
+import mods.betterfoliage.texture.LeafParticleRegistry
+import mods.betterfoliage.util.Double3
+import mods.betterfoliage.util.PI2
+import mods.betterfoliage.util.minmax
+import mods.betterfoliage.util.randomB
+import mods.betterfoliage.util.randomD
+import mods.betterfoliage.util.randomF
+import mods.betterfoliage.util.randomI
+import net.minecraft.client.Minecraft
+import net.minecraft.client.particle.IParticleRenderType
+import net.minecraft.util.math.BlockPos
+import net.minecraft.util.math.MathHelper
+import net.minecraft.world.World
+import net.minecraftforge.common.MinecraftForge
+import net.minecraftforge.event.TickEvent
+import net.minecraftforge.event.world.WorldEvent
+import net.minecraftforge.eventbus.api.SubscribeEvent
+import java.util.Random
+import kotlin.math.abs
+import kotlin.math.cos
+import kotlin.math.sin
+
+class FallingLeafParticle(
+    world: World, pos: BlockPos, leaf: LeafParticleKey, blockColor: Int, random: Random
+) : AbstractParticle(
+    world, pos.x.toDouble() + 0.5, pos.y.toDouble(), pos.z.toDouble() + 0.5
+) {
+
+    companion object {
+        @JvmStatic val biomeBrightnessMultiplier = 0.5f
+    }
+
+    var rotationSpeed = random.randomF(min = PI2 / 80.0, max = PI2 / 50.0)
+    val isMirrored = randomB()
+    var wasCollided = false
+
+    init {
+        particleAngle = random.randomF(max = PI2)
+        prevParticleAngle = particleAngle - rotationSpeed
+
+        maxAge = MathHelper.floor(randomD(0.6, 1.0) * Config.fallingLeaves.lifetime * 20.0)
+        motionY = -Config.fallingLeaves.speed
+
+        particleScale = Config.fallingLeaves.size.toFloat() * 0.1f
+        setColor(leaf.overrideColor?.asInt ?: blockColor)
+        sprite = LeafParticleRegistry[leaf.leafType][randomI(max = 1024)]
+    }
+
+    override val isValid: Boolean get() = (sprite != null)
+
+
+    override fun update() {
+        if (rand.nextFloat() > 0.95f) rotationSpeed *= -1.0f
+        if (age > maxAge - 20) particleAlpha = 0.05f * (maxAge - age)
+
+        if (onGround || wasCollided) {
+            velocity.setTo(0.0, 0.0, 0.0)
+            if (!wasCollided) {
+                age = age.coerceAtLeast(maxAge - 20)
+                wasCollided = true
+            }
+        } else {
+            val cosRotation = cos(particleAngle).toDouble(); val sinRotation = sin(particleAngle).toDouble()
+            velocity.setTo(cosRotation, 0.0, sinRotation).mul(Config.fallingLeaves.perturb)
+                .add(LeafWindTracker.current).add(0.0, -1.0, 0.0).mul(Config.fallingLeaves.speed)
+            prevParticleAngle = particleAngle
+            particleAngle += rotationSpeed
+        }
+    }
+
+    fun calculateParticleColor(textureAvgColor: Int, blockColor: Int) {
+        val texture = HSB.fromColor(textureAvgColor)
+        val block = HSB.fromColor(blockColor)
+
+        val weightTex = texture.saturation / (texture.saturation + block.saturation)
+        val weightBlock = 1.0f - weightTex
+
+        // avoid circular average for hue for performance reasons
+        // one of the color components should dominate anyway
+        val particle = HSB(
+            weightTex * texture.hue + weightBlock * block.hue,
+            weightTex * texture.saturation + weightBlock * block.saturation,
+            weightTex * texture.brightness + weightBlock * block.brightness * biomeBrightnessMultiplier
+        )
+        setColor(particle.asColor)
+    }
+
+    override fun getRenderType(): IParticleRenderType = IParticleRenderType.PARTICLE_SHEET_TRANSLUCENT
+}
+
+object LeafWindTracker {
+    var random = Random()
+    val target = Double3.zero
+    val current = Double3.zero
+    var nextChange: Long = 0
+
+    init {
+        MinecraftForge.EVENT_BUS.register(this)
+    }
+
+    fun changeWind(world: World) {
+        nextChange = world.worldInfo.gameTime + 120 + random.nextInt(80)
+        val direction = PI2 * random.nextDouble()
+        val speed = abs(random.nextGaussian()) * Config.fallingLeaves.windStrength +
+                (if (!world.isRaining) 0.0 else abs(random.nextGaussian()) * Config.fallingLeaves.stormStrength)
+        target.setTo(cos(direction) * speed, 0.0, sin(direction) * speed)
+    }
+
+    @SubscribeEvent
+    fun handleWorldTick(event: TickEvent.ClientTickEvent) {
+        if (event.phase == TickEvent.Phase.START) Minecraft.getInstance().world?.let { world ->
+            // change target wind speed
+            if (world.worldInfo.dayTime >= nextChange) changeWind(world)
+
+            // change current wind speed
+            val changeRate = if (world.isRaining) 0.015 else 0.005
+            current.add(
+                (target.x - current.x).minmax(-changeRate, changeRate),
+                0.0,
+                (target.z - current.z).minmax(-changeRate, changeRate)
+            )
+        }
+    }
+
+    @SubscribeEvent
+    fun handleWorldLoad(event: WorldEvent.Load) { if (event.world.isRemote) changeWind(event.world.world) }
+}