From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <Blake.Galbreath@GMail.com>
Date: Tue, 23 Mar 2021 19:38:53 -0500
Subject: [PATCH] Break individual slabs when sneaking


diff --git a/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java b/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
index 61ff2f6c09251da8c34fd653020cd4d3b46a4371..a810eaa7dc319f5ea69b239190ae91838bfad4ec 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
@@ -400,6 +400,7 @@ public class ServerPlayerGameMode {
                 } else {capturedBlockEntity = true;} // Paper - Send block entities after destroy prediction
                 return false;
             }
+            if (this.player.level().purpurConfig.slabHalfBreak && this.player.isShiftKeyDown() && iblockdata.getBlock() instanceof net.minecraft.world.level.block.SlabBlock && ((net.minecraft.world.level.block.SlabBlock) iblockdata.getBlock()).halfBreak(iblockdata, pos, this.player)) return true; // Purpur
         }
         // CraftBukkit end
 
diff --git a/src/main/java/net/minecraft/world/level/block/SlabBlock.java b/src/main/java/net/minecraft/world/level/block/SlabBlock.java
index fa29eb15934b3dad171d27c21d99b2451cfe553b..ba4aa69425d796d306791ea193f9c6b21a065f0b 100644
--- a/src/main/java/net/minecraft/world/level/block/SlabBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/SlabBlock.java
@@ -138,4 +138,25 @@ public class SlabBlock extends Block implements SimpleWaterloggedBlock {
                 return false;
         }
     }
+
+    // Purpur start
+    public boolean halfBreak(BlockState state, BlockPos pos, net.minecraft.server.level.ServerPlayer player) {
+        if (state.getValue(SlabBlock.TYPE) != SlabType.DOUBLE) {
+            return false;
+        }
+        net.minecraft.world.phys.HitResult result = player.getRayTrace(16, net.minecraft.world.level.ClipContext.Fluid.NONE);
+        if (result.getType() != net.minecraft.world.phys.HitResult.Type.BLOCK) {
+            return false;
+        }
+        double hitY = result.getLocation().y();
+        int blockY = org.bukkit.util.NumberConversions.floor(hitY);
+        player.level().setBlock(pos, state.setValue(SlabBlock.TYPE, (hitY - blockY > 0.5 || blockY - pos.getY() == 1) ? SlabType.BOTTOM : SlabType.TOP), 3);
+        if (!player.getAbilities().instabuild) {
+            net.minecraft.world.entity.item.ItemEntity item = new net.minecraft.world.entity.item.ItemEntity(player.level(), pos.getX(), pos.getY(), pos.getZ(), new ItemStack(asItem()));
+            item.setDefaultPickUpDelay();
+            player.level().addFreshEntity(item);
+        }
+        return true;
+    }
+    // Purpur end
 }
diff --git a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
index 76e26e67ba5bc56af28aae17ccd1da9b609e4947..c84cd3ebe3b95505a832e612c993e106d4cc1067 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -601,6 +601,11 @@ public class PurpurWorldConfig {
         }
     }
 
+    public boolean slabHalfBreak = false;
+    private void slabSettings() {
+        slabHalfBreak = getBoolean("blocks.slab.break-individual-slabs-when-sneaking", slabHalfBreak);
+    }
+
     public boolean spawnerDeactivateByRedstone = false;
     private void spawnerSettings() {
         spawnerDeactivateByRedstone = getBoolean("blocks.spawner.deactivate-by-redstone", spawnerDeactivateByRedstone);