Mushroom fixes

src/main/java/ru/betterend/util/StructureHelper.java

@@ -0,0 +1,62 @@
+package ru.betterend.util;
+
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.ChunkPos;
+import net.minecraft.world.gen.ChunkRandom;
+import net.minecraft.world.gen.chunk.StructureConfig;
+import net.minecraft.world.gen.feature.StructureFeature;
+
+public class StructureHelper {
+	private static final Set<ChunkPos> POSITIONS = new HashSet<ChunkPos>(64);
+
+	private static void collectNearby(ServerWorld world, StructureFeature<?> feature, int chunkX, int chunkZ, int radius, StructureConfig config, long worldSeed, ChunkRandom chunkRandom) {
+		int x1 = chunkX - radius;
+		int x2 = chunkX + radius;
+		int z1 = chunkZ - radius;
+		int z2 = chunkZ + radius;
+
+		POSITIONS.clear();
+		for (int x = x1; x <= x2; x += 8) {
+			for (int z = z1; z <= z2; z += 8) {
+				ChunkPos chunk = feature.getStartChunk(config, worldSeed, chunkRandom, x, z);
+				if (world.getBiome(chunk.getStartPos()).getGenerationSettings().hasStructureFeature(feature))
+					POSITIONS.add(chunk);
+			}
+		}
+	}
+
+	private static long sqr(int x) {
+		return (long) x * (long) x;
+	}
+
+	public static BlockPos getNearestStructure(StructureFeature<?> feature, ServerWorld world, BlockPos pos, int radius) {
+		int cx = pos.getX() >> 4;
+		int cz = pos.getZ() >> 4;
+
+		StructureConfig config = world.getChunkManager().getChunkGenerator().getStructuresConfig().getForType(feature);
+		if (config == null)
+			return null;
+
+		collectNearby(world, feature, cx, cz, radius, config, world.getSeed(), new ChunkRandom());
+		Iterator<ChunkPos> iterator = POSITIONS.iterator();
+		if (iterator.hasNext()) {
+			ChunkPos nearest = POSITIONS.iterator().next();
+			long d = sqr(nearest.x - cx) + sqr(nearest.z - cz);
+			while (iterator.hasNext()) {
+				ChunkPos n = iterator.next();
+				long d2 = sqr(n.x - cx) + sqr(n.z - cz);
+				if (d2 < d) {
+					d = d2;
+					nearest = n;
+				}
+			}
+			return nearest.getStartPos();
+		}
+		return null;
+	}
+}