Fixed overworld cave generation with custom bottom Y and world height values

Author: mineLdiver

station-flattening-v0/src/main/java/net/modificationstation/stationapi/impl/world/CaveGenBaseImpl.java

@@ -0,0 +1,9 @@
+package net.modificationstation.stationapi.impl.world;
+
+import net.minecraft.world.World;
+
+public interface CaveGenBaseImpl {
+    void stationapi_setWorld(World world);
+
+    World stationapi_getWorld();
+}

station-flattening-v0/src/main/java/net/modificationstation/stationapi/mixin/flattening/CaveGenBaseMixin.java

@@ -0,0 +1,25 @@
+package net.modificationstation.stationapi.mixin.flattening;
+
+import net.minecraft.class_105;
+import net.minecraft.world.World;
+import net.modificationstation.stationapi.impl.world.CaveGenBaseImpl;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+
+@Mixin(class_105.class)
+class CaveGenBaseMixin implements CaveGenBaseImpl {
+    @Unique
+    private World stationapi_world;
+
+    @Override
+    @Unique
+    public void stationapi_setWorld(World world) {
+        stationapi_world = world;
+    }
+
+    @Override
+    @Unique
+    public World stationapi_getWorld() {
+        return stationapi_world;
+    }
+}

station-flattening-v0/src/main/java/net/modificationstation/stationapi/mixin/flattening/CaveGenMixin.java

@@ -0,0 +1,61 @@
+package net.modificationstation.stationapi.mixin.flattening;
+
+import net.minecraft.class_415;
+import net.modificationstation.stationapi.api.util.math.MathHelper;
+import net.modificationstation.stationapi.impl.world.CaveGenBaseImpl;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Constant;
+import org.spongepowered.asm.mixin.injection.ModifyConstant;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+
+@Mixin(class_415.class)
+abstract class CaveGenMixin implements CaveGenBaseImpl {
+    @ModifyConstant(
+            method = "method_1400",
+            constant = {
+                    @Constant(intValue = 1, ordinal = 8),
+                    @Constant(intValue = 1, ordinal = 9)
+            }
+    )
+    private int stationapi_changeBottomYP1Cap(int constant) {
+        return Math.max(stationapi_getWorld().getBottomY() + 1, constant);
+    }
+
+    @ModifyConstant(
+            method = "method_1400",
+            constant = @Constant(intValue = 120)
+    )
+    private int stationapi_changeTopYM8Cap(int constant) {
+        return Math.min(stationapi_getWorld().getTopY() - 8, constant);
+    }
+
+    @ModifyConstant(
+            method = "method_1400",
+            constant = {
+                    @Constant(intValue = 128, ordinal = 0),
+                    @Constant(intValue = 128, ordinal = 2)
+            }
+    )
+    private int stationapi_changeHeight(int constant) {
+        return MathHelper.smallestEncompassingPowerOfTwo(stationapi_getWorld().getHeight());
+    }
+
+    @ModifyVariable(
+            method = "method_1400",
+            at = @At(value = "STORE", ordinal = 0),
+            index = 43
+    )
+    private int stationapi_adjustForCustomDepth1(int value) {
+        return value - stationapi_getWorld().getBottomY();
+    }
+
+    @ModifyVariable(
+            method = "method_1400",
+            at = @At(value = "STORE", ordinal = 0),
+            index = 46
+    )
+    private int stationapi_adjustForCustomDepth2(int value) {
+        return value - stationapi_getWorld().getBottomY();
+    }
+}

station-flattening-v0/src/main/java/net/modificationstation/stationapi/mixin/flattening/OverworldChunkGeneratorMixin.java

@@ -1,12 +1,16 @@
 package net.modificationstation.stationapi.mixin.flattening;
 
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
 import com.llamalad7.mixinextras.sugar.Share;
 import com.llamalad7.mixinextras.sugar.ref.LocalIntRef;
+import net.minecraft.class_415;
 import net.minecraft.class_538;
 import net.minecraft.world.World;
 import net.minecraft.world.biome.Biome;
 import net.minecraft.world.chunk.Chunk;
 import net.modificationstation.stationapi.api.util.math.MathHelper;
+import net.modificationstation.stationapi.impl.world.CaveGenBaseImpl;
 import net.modificationstation.stationapi.impl.world.chunk.FlattenedChunk;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
@@ -22,6 +26,19 @@ class OverworldChunkGeneratorMixin {
     @Shadow private World field_2260;
     @Shadow private double[] field_2261;
     @Unique private double[] densityCache;
+
+    @WrapOperation(
+            method = "<init>",
+            at = @At(
+                    value = "NEW",
+                    target = "()Lnet/minecraft/class_415;"
+            )
+    )
+    private class_415 stationapi_setWorldForCaveGen(Operation<class_415> original, World world, long l) {
+        final class_415 caveGen = original.call();
+        ((CaveGenBaseImpl) caveGen).stationapi_setWorld(world);
+        return caveGen;
+    }
 
     @ModifyConstant(
             method = "method_1803",

station-flattening-v0/src/main/resources/station-flattening-v0.mixins.json

@@ -7,6 +7,8 @@
     "BlockItemMixin",
     "BlockMixin",
     "BlockWithEntityMixin",
+    "CaveGenBaseMixin",
+    "CaveGenMixin",
     "ChunkAccessor",
     "ChunkCacheMixin",
     "ChunkMixin",