Improve the deep dark generation

Author: tastybento

src/main/java/world/bentobox/stranger/generator/NetherBiomeProvider.java

@@ -1,6 +1,7 @@
 package world.bentobox.stranger.generator;
 
 import java.util.List;
+import java.util.Random;
 
 import org.bukkit.block.Biome;
 import org.bukkit.generator.BiomeProvider;
@@ -11,10 +12,13 @@
  * Makes the deep dark biome
  */
 public class NetherBiomeProvider extends BiomeProvider {
+    
+    private Random random = new Random();
 
     @Override
     public @NotNull Biome getBiome(@NotNull WorldInfo worldInfo, int x, int y, int z) {
-        if (y < worldInfo.getMinHeight() + 30) {
+        final int top = worldInfo.getMinHeight() + 30 - random.nextInt(5);
+        if (y < top) {
             return Biome.DEEP_DARK;
         }
 

src/main/java/world/bentobox/stranger/generator/NetherChunks.java

@@ -37,23 +37,39 @@ public void generateNoise(@NotNull WorldInfo worldInfo, @NotNull Random random,
         // Define the Y-range for cave generation
         final int minCaveY = worldInfo.getMinHeight() + 7;
         final int maxCaveY = minCaveY + 30;
-
+        final double caveRange = (double)(maxCaveY - minCaveY);
+        
         for (int x = 0; x < 16; x++) {
             for (int z = 0; z < 16; z++) {
 
                 // Calculate absolute world X and Z once per column
                 final int worldX = chunkX * 16 + x;
                 final int worldZ = chunkZ * 16 + z;
-                for (int y = minCaveY; y < maxCaveY; y++) {
+                final int top = maxCaveY - random.nextInt(5);
+                for (int y = minCaveY; y < top ; y++) {
                     // Check the noise value
                     final int worldY = y;
                     double noise = this.caveGenerator.noise(worldX, worldY, worldZ);
-
-                    if (noise < CAVE_THRESHOLD + 0.1) {
+                    
+                    // --- DYNAMIC THRESHOLD LOGIC ---
+
+                    // 1. Get Y's progress (0.0 to 1.0) through the cave range.
+                    double yProgress = (y - minCaveY) / caveRange;
+                    
+                    // 2. Map this progress to a sine wave (0 to PI).
+                    //    Math.sin(0) = 0 (at minCaveY)
+                    //    Math.sin(PI / 2) = 1 (at the midpoint)
+                    //    Math.sin(PI) = 0 (at maxCaveY)
+                    double swellFactor = Math.sin(yProgress * Math.PI);
+                    
+                    // 3. Multiply by our max threshold.
+                    double yDependentThreshold = CAVE_THRESHOLD * swellFactor;
+
+                    if (noise < yDependentThreshold + 0.1) {
                         // Coat with Sculk
                         chunkData.setBlock(x, y, z, Material.SCULK);
                     }
-                    if (noise < CAVE_THRESHOLD) {
+                    if (noise < yDependentThreshold) {
                         // Noise value is low enough, carve a cave block
                         chunkData.setBlock(x, y, z, Material.AIR);
                     }

src/main/java/world/bentobox/stranger/listeners/NetherChunkMaker.java

@@ -310,6 +310,12 @@ private void convertBlocks(ChunkLoadEvent e) {
         for (int y = e.getWorld().getMinHeight() + NETHER_FLOOR; y < ROOF_HEIGHT; y++) {
             for (int x = 0; x < 16; x++) {
                 for (int z = 0; z < 16; z++) {
+                    if (y == e.getWorld().getMinHeight() + NETHER_FLOOR) {
+                        // Bleed some netherrack into the deep dark
+                        for (int bleed = y - rand.nextInt(5); bleed < y; bleed++ ) {
+                            e.getChunk().getBlock(x, bleed, z).setType(Material.NETHERRACK, false);
+                        }
+                    }
                     Block overworldBlock = overworldChunk.getBlock(x, y, z);
                     Block newBlock = e.getChunk().getBlock(x, y, z);
                     newBlock.setBiome(BIOME_MAPPING.getOrDefault(overworldBlock.getBiome(), Biome.NETHER_WASTES)); // Set biome for the new block
@@ -333,8 +339,7 @@ private void convertBlocks(ChunkLoadEvent e) {
 
                     // Biome
                     if (overworldBlock.getBiome() == Biome.DEEP_DARK) {
-                        // Replicate the creepy deep dark
-                        
+                        // Replicate the creepy deep dark                      
                     } else 
                         // --- Tag-Based Conversion ---