Replace getBlockRandomPos implementation

src/main/java/ru/dbotthepony/mc/prng/mixin/LevelMixin.java

@@ -0,0 +1,18 @@
+package ru.dbotthepony.mc.prng.mixin;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.Level;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+
+@Mixin(Level.class)
+public abstract class LevelMixin {
+	@Overwrite
+	public BlockPos getBlockRandomPos(int x, int y, int z, int yMask) {
+		long value = ((Level) (Object) this).random.nextLong();
+		int selectX = (int) (value & 15);
+		int selectZ = (int) ((value >>> 8) & 15);
+		int selectY = (int) ((value >>> 16) & yMask);
+		return new BlockPos(selectX + x, selectY + y, selectZ + z);
+	}
+}

src/main/resources/better_random.mixins.json

@@ -5,7 +5,8 @@
   "compatibilityLevel": "JAVA_21",
   "minVersion": "0.8",
   "mixins": [
-    "RandomSourceMixin"
+    "RandomSourceMixin",
+    "LevelMixin"
   ],
   "client": []
 }