Add getHeight method to ChunkData (#12311)

Author: ShaneBeee

paper-api/src/main/java/org/bukkit/generator/ChunkGenerator.java

@@ -14,6 +14,7 @@
 import org.bukkit.material.MaterialData;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.Range;
 
 /**
  * A chunk generator is responsible for the initial shaping of an entire
@@ -777,5 +778,18 @@ public static interface ChunkData {
          */
         @Deprecated(since = "1.8.8")
         public byte getData(int x, int y, int z);
+
+        /**
+         * Get the current height of a position in the chunk data.
+         * <p>This will differ based on which state generation of the chunk is currently at.
+         * If for example the chunk is in the generate surface stage,
+         * this will return what was already generated in the noise stage.</p>
+         *
+         * @param heightMap Heightmap to determine where to grab height
+         * @param x the x location in the chunk from 0-15 inclusive
+         * @param z the z location in the chunk from 0-15 inclusive
+         * @return Y coordinate at highest position
+         */
+        int getHeight(@NotNull HeightMap heightMap, @Range(from = 0L, to = 15L) int x, @Range(from = 0L, to = 15L) int z);
     }
 }

paper-server/src/main/java/org/bukkit/craftbukkit/generator/CraftChunkData.java

@@ -8,12 +8,13 @@
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.chunk.ChunkAccess;
+import org.bukkit.HeightMap;
 import org.bukkit.Material;
 import org.bukkit.World;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
+import org.bukkit.craftbukkit.CraftHeightMap;
 import org.bukkit.craftbukkit.block.CraftBiome;
-import org.bukkit.craftbukkit.block.CraftBlockType;
 import org.bukkit.craftbukkit.block.data.CraftBlockData;
 import org.bukkit.craftbukkit.util.CraftMagicNumbers;
 import org.bukkit.generator.ChunkGenerator;
@@ -180,4 +181,12 @@ private void setBlock(int x, int y, int z, BlockState type) {
             access.removeBlockEntity(blockPosition);
         }
     }
+
+    @Override
+    public int getHeight(final HeightMap heightMap, final int x, final int z) {
+        Preconditions.checkArgument(heightMap != null, "HeightMap cannot be null");
+        Preconditions.checkArgument(x >= 0 && x <= 15 && z >= 0 && z <= 15, "Cannot get height outside of a chunks bounds, must be between 0 and 15, got x: %s, z: %s", x, z);
+
+        return getHandle().getHeight(CraftHeightMap.toNMS(heightMap), x, z);
+    }
 }

paper-server/src/main/java/org/bukkit/craftbukkit/generator/OldCraftChunkData.java

@@ -8,6 +8,7 @@
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.chunk.LevelChunkSection;
+import org.bukkit.HeightMap;
 import org.bukkit.Material;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
@@ -200,4 +201,9 @@ Set<BlockPos> getTiles() {
     Set<BlockPos> getLights() {
         return this.lights;
     }
+
+    @Override
+    public int getHeight(HeightMap heightMap, final int x, final int z) {
+        throw new UnsupportedOperationException("Unsupported, in older chunk generator api");
+    }
 }