feat: fire event to allow custom min-Y calculator registration

Author: desht

common/src/main/java/dev/ftb/mods/ftbchunks/CustomMinYRegistryImpl.java

@@ -0,0 +1,35 @@
+package dev.ftb.mods.ftbchunks;
+
+import dev.ftb.mods.ftbchunks.api.LevelMinYCalculator;
+import dev.ftb.mods.ftbchunks.api.event.CustomMinYEvent;
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.Level;
+
+import java.util.List;
+import java.util.OptionalInt;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+public class CustomMinYRegistryImpl implements CustomMinYEvent.CustomMinYRegistry {
+    private static final CustomMinYRegistryImpl serverInstance = new CustomMinYRegistryImpl();
+    private static final CustomMinYRegistryImpl clientInstance = new CustomMinYRegistryImpl();
+
+    private final List<LevelMinYCalculator> calculators = new CopyOnWriteArrayList<>();  // needs to be threadsafe
+
+    public static CustomMinYRegistryImpl getInstance(boolean isClientSide) {
+        return isClientSide ? clientInstance : serverInstance;
+    }
+
+    public void register(LevelMinYCalculator calculator) {
+        calculators.add(calculator);
+    }
+
+    public int getMinYAt(Level level, BlockPos pos) {
+        for (var calc : calculators) {
+            OptionalInt h = calc.getLevelMinY(level, pos);
+            if (h.isPresent()) {
+                return h.getAsInt();
+            }
+        }
+        return level.getMinBuildHeight();
+    }
+}

common/src/main/java/dev/ftb/mods/ftbchunks/FTBChunks.java

@@ -14,6 +14,7 @@
 import dev.architectury.utils.EnvExecutor;
 import dev.architectury.utils.value.IntValue;
 import dev.ftb.mods.ftbchunks.api.*;
+import dev.ftb.mods.ftbchunks.api.event.CustomMinYEvent;
 import dev.ftb.mods.ftbchunks.client.FTBChunksClient;
 import dev.ftb.mods.ftbchunks.client.FTBChunksClientConfig;
 import dev.ftb.mods.ftbchunks.data.*;
@@ -133,6 +134,10 @@ public FTBChunks() {
 		TickEvent.PLAYER_POST.register(this::playerTickPost);
 
 		EnvExecutor.runInEnv(Env.CLIENT, () -> FTBChunksClient.INSTANCE::init);
+
+		LifecycleEvent.SETUP.register(() ->
+				CustomMinYEvent.REGISTER.invoker().register(CustomMinYRegistryImpl.getInstance(Platform.getEnvironment() == Env.CLIENT))
+		);
 	}
 
 	private EventResult playerAttackEntity(Player player, Level level, Entity entity, InteractionHand interactionHand, @Nullable EntityHitResult entityHitResult) {

common/src/main/java/dev/ftb/mods/ftbchunks/api/LevelMinYCalculator.java

@@ -0,0 +1,18 @@
+package dev.ftb.mods.ftbchunks.api;
+
+import dev.ftb.mods.ftbchunks.api.event.CustomMinYEvent;
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.Level;
+
+import java.util.OptionalInt;
+
+/**
+ * Functional interface to allow custom minimum Y levels to be returned for a given dimension and block position.
+ * The intention of this is to allow for custom areas of a map to be concealed from FTB Chunks mapping.
+ * <p>
+ * Listen to the Architectury {@link CustomMinYEvent} event to register this method, on both client and server.
+ */
+@FunctionalInterface
+public interface LevelMinYCalculator {
+    OptionalInt getLevelMinY(Level level, BlockPos pos);
+}

common/src/main/java/dev/ftb/mods/ftbchunks/api/event/CustomMinYEvent.java

@@ -0,0 +1,15 @@
+package dev.ftb.mods.ftbchunks.api.event;
+
+import dev.architectury.event.Event;
+import dev.architectury.event.EventFactory;
+import dev.ftb.mods.ftbchunks.api.LevelMinYCalculator;
+
+public interface CustomMinYEvent {
+    Event<CustomMinYEvent> REGISTER = EventFactory.createLoop();
+
+    void register(CustomMinYRegistry registry);
+
+    interface CustomMinYRegistry {
+        void register(LevelMinYCalculator calculator);
+    }
+}

common/src/main/java/dev/ftb/mods/ftbchunks/util/HeightUtils.java

@@ -1,8 +1,8 @@
 package dev.ftb.mods.ftbchunks.util;
 
+import dev.ftb.mods.ftbchunks.CustomMinYRegistryImpl;
 import dev.ftb.mods.ftbchunks.FTBChunksWorldConfig;
 import dev.ftb.mods.ftbchunks.client.FTBChunksClient;
-import dev.ftb.mods.ftbchunks.client.FTBChunksClientConfig;
 import dev.ftb.mods.ftbchunks.core.BlockStateFTBC;
 import net.minecraft.core.BlockPos;
 import net.minecraft.util.Mth;
@@ -43,14 +43,15 @@ public static int getHeight(Level level, @Nullable ChunkAccess chunkAccess, Bloc
 			return UNKNOWN;
 		}
 
-        int chunkX = pos.getX() >> 4;
-        int chunkZ = pos.getZ() >> 4;
+//        int chunkX = pos.getX() >> 4;
+//        int chunkZ = pos.getZ() >> 4;
 
         // Clamped within the dimensions build height limits
-        int startY = FTBChunksWorldConfig.OVERRIDE_MIN_Y_LEVEL.get()
-                ? getMinYFromChunkOrConfig(chunkX, chunkZ)
-                : chunkAccess.getMinBuildHeight();
+//        int startY = FTBChunksWorldConfig.OVERRIDE_MIN_Y_LEVEL.get()
+//                ? getMinYFromChunkOrConfig(chunkX, chunkZ)
+//                : chunkAccess.getMinBuildHeight();
 
+		int startY = CustomMinYRegistryImpl.getInstance(level.isClientSide).getMinYAt(level, pos);
 		int bottomY = Mth.clamp(startY, chunkAccess.getMinBuildHeight(), chunkAccess.getMaxBuildHeight());
 
 		int topY = pos.getY();