add behaviour for wild pokemon to hide in grass #122

common/src/main/kotlin/com/cobblemon/mod/common/entity/pokemon/PokemonEntity.kt

@@ -745,6 +745,7 @@ open class PokemonEntity(
         goalSelector.addGoal(4, PokemonMoveIntoFluidGoal(this))
         goalSelector.addGoal(5, SleepOnTrainerGoal(this))
         goalSelector.addGoal(5, WildRestGoal(this))
+        goalSelector.addGoal(5, PokemonHideInGrassGoal(this))
 
         if (pokemon.getFeature<FlagSpeciesFeature>(DataKeys.HAS_BEEN_SHEARED) != null) {
             goalSelector.addGoal(5, EatBlockGoal(this))

common/src/main/kotlin/com/cobblemon/mod/common/entity/pokemon/ai/goals/PokemonHideInGrassGoal.kt

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2023 Cobblemon Contributors
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+package com.cobblemon.mod.common.entity.pokemon.ai.goals
+
+import com.cobblemon.mod.common.entity.pokemon.PokemonEntity
+import com.cobblemon.mod.common.util.toVec3d
+import net.minecraft.core.BlockPos
+import net.minecraft.world.entity.ai.goal.Goal
+import net.minecraft.world.level.block.Blocks
+import net.minecraft.world.level.block.state.BlockState
+import net.minecraft.world.phys.AABB
+
+class PokemonHideInGrassGoal(private val pokemonEntity: PokemonEntity): Goal() {
+
+    companion object {
+        private const val GRASS_SEARCH_HORIZONTAL_RANGE = 16.0
+        private const val GRASS_SEARCH_VERTICAL_RANGE = 2.0
+        private val SECONDS_IN_SAME_GRASS = 5 .. 10
+        private val VALID_GRASS_BLOCKS = setOf(
+            Blocks.SHORT_GRASS,
+            Blocks.TALL_GRASS,
+            Blocks.FERN,
+            Blocks.LARGE_FERN,
+        )
+    }
+
+    private var pickedGrassBlockPos: BlockPos? = null
+    private var ticksInGrass = 0
+    private var wantedTicksInGrass = 0
+
+    override fun canUse(): Boolean =
+        pokemonEntity.pokemon.species.behaviour.moving.hideInGrass
+        && pokemonEntity.pokemon.isWild()
+        && getNearbyGrassBlocks().isNotEmpty()
+
+    override fun start() {
+        super.start()
+
+        pickedGrassBlockPos = getNearbyGrassBlocks().random()
+        ticksInGrass = 0
+        wantedTicksInGrass = pokemonEntity.random.nextIntBetweenInclusive(SECONDS_IN_SAME_GRASS.first, SECONDS_IN_SAME_GRASS.last) * 20
+    }
+
+    override fun tick() {
+        super.tick()
+
+        val grassBlockCenterPos = pickedGrassBlockPos?.bottomCenter ?: return stop()
+        val couldMoveToGrass = pokemonEntity.navigation.moveTo(
+            grassBlockCenterPos.x,
+            grassBlockCenterPos.y,
+            grassBlockCenterPos.z,
+            1.0
+        )
+
+        if (!couldMoveToGrass) return stop()
+
+        ticksInGrass++
+    }
+
+    override fun canContinueToUse(): Boolean {
+        if (ticksInGrass >= wantedTicksInGrass) return false
+
+        pickedGrassBlockPos?.let {
+            val grassStillExists =  isGrass(pokemonEntity.level().getBlockState(it))
+            if (!grassStillExists) return false
+
+            val grassBox = AABB.ofSize(it.toVec3d(), 0.5, 0.5, 0.5)
+            val isGrassOccupiedByAnotherEntity = pokemonEntity.level().getEntities(pokemonEntity, grassBox).isNotEmpty()
+            if (isGrassOccupiedByAnotherEntity) {
+                return false
+            }
+        } ?: return false
+
+        return true
+    }
+
+    override fun stop() {
+        super.stop()
+
+        pickedGrassBlockPos = null
+        ticksInGrass = 0
+        pokemonEntity.navigation.stop()
+    }
+
+    private fun getNearbyGrassBlocks(): List<BlockPos> {
+        val searchBox = AABB.ofSize(
+            pokemonEntity.position(),
+            GRASS_SEARCH_HORIZONTAL_RANGE,
+            GRASS_SEARCH_VERTICAL_RANGE,
+            GRASS_SEARCH_HORIZONTAL_RANGE
+        )
+
+        val grassBlocks: MutableList<BlockPos> = mutableListOf()
+        BlockPos.betweenClosedStream(searchBox).forEach {
+            val blockState = pokemonEntity.level().getBlockState(it)
+            if (isGrass(blockState)) {
+                grassBlocks.add(BlockPos(it))
+            }
+        }
+
+        return grassBlocks
+    }
+
+    private fun isGrass(blockState: BlockState): Boolean = VALID_GRASS_BLOCKS.contains(blockState.block)
+}

common/src/main/kotlin/com/cobblemon/mod/common/pokemon/ai/MoveBehaviour.kt

@@ -23,4 +23,5 @@ class MoveBehaviour {
     val wanderSpeed = 1.0
     val canLook = true
     val looksAtEntities = true
+    val hideInGrass = false
 }