override entity spawning stuff

platforms/fabric/src/main/java/com/dfsek/terra/fabric/generation/FabricChunkGeneratorWrapper.java

@@ -20,6 +20,7 @@ import com.mojang.serialization.codecs.RecordCodecBuilder;
 import net.jafama.FastMath;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.Blocks;
+import net.minecraft.entity.SpawnGroup;
 import net.minecraft.server.world.ServerWorld;
 import net.minecraft.structure.StructureManager;
 import net.minecraft.util.math.BlockPos;
@@ -32,6 +33,7 @@ import net.minecraft.world.Heightmap;
 import net.minecraft.world.SpawnHelper;
 import net.minecraft.world.WorldAccess;
 import net.minecraft.world.biome.Biome;
+import net.minecraft.world.biome.SpawnSettings;
 import net.minecraft.world.biome.source.BiomeAccess;
 import net.minecraft.world.chunk.Chunk;
 import net.minecraft.world.dimension.DimensionType;
@@ -44,6 +46,7 @@ import net.minecraft.world.gen.chunk.VerticalBlockSample;
 import net.minecraft.world.gen.feature.StructureFeature;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -173,6 +176,27 @@ public class FabricChunkGeneratorWrapper extends ChunkGenerator implements Gener
         return new VerticalBlockSample(array);
     }
 
+    @Override
+    public List<SpawnSettings.SpawnEntry> getEntitySpawnList(Biome biome, StructureAccessor accessor, SpawnGroup group, BlockPos pos) {
+        if(pack.getTemplate().vanillaStructures()) {
+            if(accessor.getStructureAt(pos, true, StructureFeature.SWAMP_HUT).hasChildren()) {
+                if(group == SpawnGroup.MONSTER) return StructureFeature.SWAMP_HUT.getMonsterSpawns();
+                if(group == SpawnGroup.CREATURE) return StructureFeature.SWAMP_HUT.getCreatureSpawns();
+            }
+
+            if(group == SpawnGroup.MONSTER) {
+                if(accessor.getStructureAt(pos, false, StructureFeature.PILLAGER_OUTPOST).hasChildren()) {
+                    return StructureFeature.PILLAGER_OUTPOST.getMonsterSpawns();
+                } else if(accessor.getStructureAt(pos, false, StructureFeature.MONUMENT).hasChildren()) {
+                    return StructureFeature.MONUMENT.getMonsterSpawns();
+                } else if(accessor.getStructureAt(pos, true, StructureFeature.FORTRESS).hasChildren()) {
+                    return StructureFeature.FORTRESS.getMonsterSpawns();
+                }
+            }
+        }
+        return super.getEntitySpawnList(biome, accessor, group, pos);
+    }
+
     @Override
     public void populateEntities(ChunkRegion region) {
         if(pack.getTemplate().vanillaMobs()) {

platforms/forge/src/main/java/com/dfsek/terra/forge/generation/ForgeChunkGeneratorWrapper.java

@@ -20,6 +20,7 @@ import com.mojang.serialization.codecs.RecordCodecBuilder;
 import net.jafama.FastMath;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.Blocks;
+import net.minecraft.entity.EntityClassification;
 import net.minecraft.util.SharedSeedRandom;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.ChunkPos;
@@ -31,6 +32,7 @@ import net.minecraft.world.IBlockReader;
 import net.minecraft.world.IWorld;
 import net.minecraft.world.biome.Biome;
 import net.minecraft.world.biome.BiomeManager;
+import net.minecraft.world.biome.MobSpawnInfo;
 import net.minecraft.world.chunk.IChunk;
 import net.minecraft.world.gen.ChunkGenerator;
 import net.minecraft.world.gen.GenerationStage;
@@ -45,6 +47,7 @@ import net.minecraft.world.spawner.WorldEntitySpawner;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -181,6 +184,13 @@ public class ForgeChunkGeneratorWrapper extends ChunkGenerator implements Genera
         }
     }
 
+    @Override
+    public List<MobSpawnInfo.Spawners> getMobsAt(Biome p_230353_1_, StructureManager p_230353_2_, EntityClassification p_230353_3_, BlockPos p_230353_4_) {
+        List<MobSpawnInfo.Spawners> spawns = net.minecraftforge.common.world.StructureSpawnManager.getStructureSpawns(p_230353_2_, p_230353_3_, p_230353_4_);
+        if(spawns != null) return spawns;
+        return super.getMobsAt(p_230353_1_, p_230353_2_, p_230353_3_, p_230353_4_);
+    }
+
     @Override
     public TerraChunkGenerator getHandle() {
         return delegate;