Make blackstone gateways rarely spawn in bastions

src/main/java/org/dimdev/dimdoors/mixin/StructurePoolMixin.java

@@ -0,0 +1,32 @@
+package org.dimdev.dimdoors.mixin;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Function;
+
+import com.mojang.datafixers.util.Pair;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+
+import net.minecraft.structure.pool.StructurePool;
+import net.minecraft.structure.pool.StructurePoolElement;
+import net.minecraft.structure.processor.StructureProcessorLists;
+import net.minecraft.util.Identifier;
+
+@Mixin(StructurePool.class)
+public class StructurePoolMixin {
+	@Unique
+	private static final Identifier HOUSES_ID = new Identifier("bastion/treasure/extensions/houses");
+
+	@ModifyVariable(method = "<init>(Lnet/minecraft/util/Identifier;Lnet/minecraft/util/Identifier;Ljava/util/List;Lnet/minecraft/structure/pool/StructurePool$Projection;)V", at = @At("HEAD"))
+	private static List<Pair<Function<StructurePool.Projection, ? extends StructurePoolElement>, Integer>> thing(List<Pair<Function<StructurePool.Projection, ? extends StructurePoolElement>, Integer>> list, Identifier id, Identifier terminatorsId, List<Pair<Function<StructurePool.Projection, ? extends StructurePoolElement>, Integer>> elementCounts, StructurePool.Projection projection) {
+		if (id.equals(HOUSES_ID)) {
+			List<Pair<Function<StructurePool.Projection, ? extends StructurePoolElement>, Integer>> copy = new ArrayList<>(list);
+			copy.add(Pair.of(StructurePoolElement.method_30435("dimdoors:bastion/treasure/houses/bastion_gateway", StructureProcessorLists.TREASURE_ROOMS), 1));
+			return copy;
+		}
+		return list;
+	}
+}

src/main/resources/dimdoors.mixins.json

@@ -12,6 +12,7 @@
     "RegistryKeyMixin",
     "ServerPlayerEntityMixin",
     "ServerPlayerInteractionManagerMixin",
+    "StructurePoolMixin",
     "accessor.BuiltinBiomesAccessor",
     "accessor.ChunkGeneratorAccessor",
     "accessor.DefaultParticleTypeAccessor",