Greatly enhance ender teleporter position validation

src/main/kotlin/ru/dbotthepony/mc/otm/android/feature/EnderTeleporterFeature.kt

@@ -12,15 +12,15 @@ import net.minecraft.resources.ResourceLocation
 import net.minecraft.server.level.ServerPlayer
 import net.minecraft.sounds.SoundEvents
 import net.minecraft.sounds.SoundSource
+import net.minecraft.tags.BlockTags
 import net.minecraft.world.level.ClipContext
 import net.minecraft.world.level.block.Block
-import net.minecraft.world.level.material.Material
 import net.minecraft.world.phys.HitResult
+import net.minecraft.world.phys.shapes.BooleanOp
 import net.minecraft.world.phys.shapes.CollisionContext
+import net.minecraft.world.phys.shapes.Shapes
 import net.minecraftforge.client.event.RenderLevelStageEvent
 import net.minecraftforge.event.entity.living.LivingDeathEvent
-import org.lwjgl.opengl.GL11.GL_ALWAYS
-import org.lwjgl.opengl.GL11.GL_LESS
 import ru.dbotthepony.mc.otm.NULLABLE_MINECRAFT_SERVER
 import ru.dbotthepony.mc.otm.OverdriveThatMatters
 import ru.dbotthepony.mc.otm.ServerConfig
@@ -29,7 +29,6 @@ import ru.dbotthepony.mc.otm.android.AndroidResearchManager
 import ru.dbotthepony.mc.otm.capability.MatteryPlayerCapability
 import ru.dbotthepony.mc.otm.capability.extractEnergyInnerExact
 import ru.dbotthepony.mc.otm.capability.matteryPlayer
-import ru.dbotthepony.mc.otm.client.minecraft
 import ru.dbotthepony.mc.otm.client.render.DynamicBufferSource
 import ru.dbotthepony.mc.otm.client.render.ResearchIcons
 import ru.dbotthepony.mc.otm.client.render.element
@@ -42,6 +41,7 @@ import ru.dbotthepony.mc.otm.core.component2
 import ru.dbotthepony.mc.otm.core.component3
 import ru.dbotthepony.mc.otm.core.formatPower
 import ru.dbotthepony.mc.otm.core.genericPositions
+import ru.dbotthepony.mc.otm.core.minus
 import ru.dbotthepony.mc.otm.core.plus
 import ru.dbotthepony.mc.otm.core.set
 import ru.dbotthepony.mc.otm.core.shortestDistanceBetween
@@ -74,23 +74,43 @@ class EnderTeleporterFeature(capability: MatteryPlayerCapability) : AndroidActiv
 		cooldown = nbt.getInt("cooldown")
 	}
 
+	private fun isValidGround(blockPos: BlockPos): Boolean {
+		return canSupportPlayer(blockPos) && !isWall(blockPos)
+	}
+
+	private fun canSupportPlayer(blockPos: BlockPos): Boolean {
+		val state = ply.level.getBlockState(blockPos)
+
+		if (state.`is`(BlockTags.CLIMBABLE)) {
+			return true // ladders can always support player
+		}
+
+		val shape = state.getCollisionShape(ply.level, blockPos, CollisionContext.of(ply))
+		return Shapes.joinIsNotEmpty(shape, SHAPE_CHECK_SUPPORT_PLAYER, BooleanOp.AND)
+	}
+
+	private fun isWall(blockPos: BlockPos): Boolean {
+		val shape = ply.level.getBlockState(blockPos).getCollisionShape(ply.level, blockPos, CollisionContext.of(ply))
+		return Shapes.joinIsNotEmpty(shape, SHAPE_CHECK_NOT_FENCE, BooleanOp.AND)
+	}
+
+	private fun isAirGap(blockPos: BlockPos): Boolean {
+		val state = ply.level.getBlockState(blockPos)
+
+		if (state.isAir) {
+			return true
+		}
+
+		val shape = state.getCollisionShape(ply.level, blockPos, CollisionContext.of(ply))
+		return shape.isEmpty || !Shapes.joinIsNotEmpty(shape, SHAPE_CHECK_SUPPORT_PLAYER, BooleanOp.AND)
+	}
+
 	private fun isValidPosition(blockPos: BlockPos): Boolean {
-		if (!Block.canSupportCenter(ply.level, blockPos.below(), Direction.UP) && !Block.canSupportRigidBlock(ply.level, blockPos.below()) && ply.level.getBlockState(blockPos.below()).material != Material.LEAVES) {
+		if (!canSupportPlayer(blockPos.below()) && !isWall(blockPos.below().below())) {
 			return false
 		}
 
-		val a = ply.level.getBlockState(blockPos)
+		return !isWall(blockPos.below()) && isAirGap(blockPos) && isAirGap(blockPos.above())
-		val b = ply.level.getBlockState(blockPos.above())
-
-		if (a.isAir && b.isAir) {
-			return true
-		}
-
-		if (a.getCollisionShape(ply.level, blockPos).isEmpty && b.getCollisionShape(ply.level, blockPos, CollisionContext.of(ply)).isEmpty) {
-			return true
-		}
-
-		return false
 	}
 
 	private data class TraceResult(val pos: BlockPos? = null, val phasedBlocks: Collection<BlockPos> = listOf()) {
@@ -115,22 +135,36 @@ class EnderTeleporterFeature(capability: MatteryPlayerCapability) : AndroidActiv
 			return TraceResult.EMPTY
 		}
 
+		val testPositions = ply.genericPositions()
+
 		if (
 			result.direction == Direction.UP &&
 			isValidPosition(result.blockPos.above()) &&
-			shortestDistanceBetween(ply.genericPositions(), result.blockPos.above().asVector()) <= ServerConfig.EnderTeleporter.MAX_DISTANCE
+			shortestDistanceBetween(testPositions, result.blockPos.above().asVector()) <= ServerConfig.EnderTeleporter.MAX_DISTANCE
 		) {
 			return TraceResult(result.blockPos.above())
 		}
 
-		for (y in 0 .. ServerConfig.EnderTeleporter.MAX_PHASE_DISTANCE) {
+		for (y in (if (ply.level.getBlockState(result.blockPos).`is`(BlockTags.CLIMBABLE)) -1 else 0) .. ServerConfig.EnderTeleporter.MAX_PHASE_DISTANCE) {
-			val pos = result.blockPos + BlockPos(0, y + 1, 0)
+			val pos = BlockPos(result.blockPos.x, result.blockPos.y + y + 1, result.blockPos.z)
 
-			if (isValidPosition(pos) && shortestDistanceBetween(ply.genericPositions(), pos.asVector()) <= ServerConfig.EnderTeleporter.MAX_DISTANCE) {
+			if (isValidPosition(pos) && shortestDistanceBetween(testPositions, pos.asVector()) <= ServerConfig.EnderTeleporter.MAX_DISTANCE) {
 				return TraceResult(pos, if (y != 0) ImmutableList(y + 1) { result.blockPos + BlockPos(0, it, 0) } else listOf())
 			}
 		}
 
+		// no valid positions...
+		if (isAirGap(result.blockPos)) {
+			// try to find ground below...
+			for (y in 0 downTo -ServerConfig.EnderTeleporter.MAX_PHASE_DISTANCE) {
+				val pos = BlockPos(result.blockPos.x, result.blockPos.y + y, result.blockPos.z)
+
+				if (isValidPosition(pos) && shortestDistanceBetween(testPositions, pos.asVector()) <= ServerConfig.EnderTeleporter.MAX_DISTANCE) {
+					return TraceResult(pos, if (y != 0) ImmutableList(-y + 1) { result.blockPos - BlockPos(0, it, 0) } else listOf())
+				}
+			}
+		}
+
 		return TraceResult.EMPTY
 	}
 
@@ -237,6 +271,9 @@ class EnderTeleporterFeature(capability: MatteryPlayerCapability) : AndroidActiv
 			DynamicBufferSource(maximalInitialBufferSize = 256)
 		}
 
+		private val SHAPE_CHECK_NOT_FENCE = Block.box(6.0, 17.0, 6.0, 10.0, 31.0, 10.0)
+		private val SHAPE_CHECK_SUPPORT_PLAYER = Block.box(6.0, 0.0, 6.0, 10.0, 16.0, 10.0)
+
 		val SPRITE = ResourceLocation(OverdriveThatMatters.MOD_ID, "textures/item/black_hole.png").element(0f, 0f, 16f, 16f, 16f, 16f)
 
 		val POWER_COST_DESCRIPTION =