First mock of an improved nether-render mode

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/mca/MCAChunk.java

@@ -30,25 +30,33 @@
 import net.querz.nbt.CompoundTag;
 
 import java.io.IOException;
+import java.util.Arrays;
 
 public abstract class MCAChunk implements Chunk {
 
     private final MCAWorld world;
     private final int dataVersion;
 
+    private int[] netherCeilingHeights;
+
     protected MCAChunk() {
-        this.world = null;
+        this(null, -1);
-        this.dataVersion = -1;
     }
 
     protected MCAChunk(MCAWorld world) {
-        this.world = world;
+        this(world, -1);
-        this.dataVersion = -1;
     }
 
     protected MCAChunk(MCAWorld world, CompoundTag chunkTag) {
+        this(world, chunkTag.getInt("DataVersion"));
+    }
+
+    private MCAChunk(MCAWorld world, int dataVersion) {
         this.world = world;
-        dataVersion = chunkTag.getInt("DataVersion");
+        this.dataVersion = dataVersion;
+
+        this.netherCeilingHeights = new int[16 * 16];
+        Arrays.fill(this.netherCeilingHeights, Integer.MIN_VALUE);
     }
 
     @Override
@@ -86,6 +94,26 @@ public int getMinY(int x, int z) {
     @Override
     public int getOceanFloorY(int x, int z) { return 0; }
 
+    @Override
+    public int getNetherCeilingY(int x, int z) {
+        int lx = x & 0xF, lz = z & 0xF;
+        int i = lz * 16 + lx;
+        int y = netherCeilingHeights[i];
+
+        if (y == Integer.MIN_VALUE) {
+            int maxY = getMaxY(x, z);
+            int minY = getMinY(x, z);
+
+            for (y = Math.min(maxY, 120); y >= minY; y--){
+                if (!getBlockState(x, y, z).isNetherCeiling()) break;
+            }
+
+            netherCeilingHeights[i] = y;
+        }
+
+        return y;
+    }
+
     protected MCAWorld getWorld() {
         return world;
     }

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/world/Block.java

@@ -136,7 +136,10 @@ public Chunk getChunk() {
     }
 
     public BlockState getBlockState() {
-        if (blockState == null) blockState = getChunk().getBlockState(x, y, z);
+        if (blockState == null){
+            if (y > getChunk().getNetherCeilingY(x, z)) blockState = BlockState.AIR;
+            else blockState = getChunk().getBlockState(x, y, z);
+        }
         return blockState;
     }
 

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/world/BlockState.java

@@ -53,7 +53,7 @@ public class BlockState extends Key {
     private final Map<String, String> properties;
     private final Property[] propertiesArray;
 
-    private final boolean isAir, isWater, isWaterlogged;
+    private final boolean isAir, isWater, isWaterlogged, isNetherCeiling;
     private int liquidLevel = -1, redstonePower = -1;
 
     public BlockState(String value) {
@@ -82,6 +82,17 @@ public BlockState(String value, Map<String, String> properties) {
         this.isWater = "minecraft:water".equals(this.getFormatted());
         this.isWaterlogged = "true".equals(properties.get("waterlogged"));
 
+        this.isNetherCeiling =
+                "minecraft:bedrock".equals(this.getFormatted()) ||
+                "minecraft:netherrack".equals(this.getFormatted()) ||
+                "minecraft:nether_quartz_ore".equals(this.getFormatted()) ||
+                "minecraft:lava".equals(this.getFormatted()) ||
+                "minecraft:soul_sand".equals(this.getFormatted()) ||
+                "minecraft:basalt".equals(this.getFormatted()) ||
+                "minecraft:blackstone".equals(this.getFormatted()) ||
+                "minecraft:soul_soil".equals(this.getFormatted()) ||
+                "minecraft:nether_gold_ore".equals(this.getFormatted()) ||
+                "minecraft:ancient_debris".equals(this.getFormatted());
     }
 
     /**
@@ -109,6 +120,10 @@ public boolean isWaterlogged() {
         return isWaterlogged;
     }
 
+    public boolean isNetherCeiling() {
+        return isNetherCeiling;
+    }
+
     public int getLiquidLevel() {
         if (liquidLevel == -1) {
             try {

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/world/Chunk.java

@@ -44,4 +44,6 @@ public interface Chunk {
 
     int getOceanFloorY(int x, int z);
 
+    int getNetherCeilingY(int x, int z);
+    
 }

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/world/EmptyChunk.java

@@ -69,4 +69,9 @@ public int getMinY(int x, int z) {
     @Override
     public int getOceanFloorY(int x, int z) { return 0; }
 
+    @Override
+    public int getNetherCeilingY(int x, int z) {
+        return 0;
+    }
+
 }