Paper/patches/server/0751-Lag-compensate-block-breaking.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <spottedleaf@spottedleaf.dev>
Date: Fri, 14 Feb 2020 22:16:34 -0800
Subject: [PATCH] Lag compensate block breaking

Use time instead of ticks if ticks fall behind

diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index da3eca94623a81d178166cc4689bb95a829837cc..d673f1d051f943c65bceccc2c8d8172e3259abb4 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -619,4 +619,10 @@ public class PaperConfig {
             }
         }
     }
+
+    public static boolean lagCompensateBlockBreaking;
+
+    private static void lagCompensateBlockBreaking() {
+        lagCompensateBlockBreaking = getBoolean("settings.lag-compensate-block-breaking", true);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java b/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
index b6eef41079120fffd63f06f681378b1b628b95e0..891199d02539fa46454cd0aa7c133637e5dc8235 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayerGameMode.java
@@ -56,14 +56,28 @@ public class ServerPlayerGameMode {
     @Nullable
     private GameType previousGameModeForPlayer;
     private boolean isDestroyingBlock;
-    private int destroyProgressStart;
+    private int destroyProgressStart; private long lastDigTime; // Paper - lag compensate block breaking
     private BlockPos destroyPos;
     private int gameTicks;
     private boolean hasDelayedDestroy;
     private BlockPos delayedDestroyPos;
-    private int delayedTickStart;
+    private int delayedTickStart; private long hasDestroyedTooFastStartTime; // Paper - lag compensate block breaking
     private int lastSentState;
 
+    // Paper start - lag compensate block breaking
+    private int getTimeDiggingLagCompensate() {
+        int lagCompensated = (int)((System.nanoTime() - this.lastDigTime) / (50L * 1000L * 1000L));
+        int tickDiff = this.gameTicks - this.destroyProgressStart;
+        return (com.destroystokyo.paper.PaperConfig.lagCompensateBlockBreaking && lagCompensated > (tickDiff + 1)) ? lagCompensated : tickDiff; // add one to ensure we don't lag compensate unless we need to
+    }
+
+    private int getTimeDiggingTooFastLagCompensate() {
+        int lagCompensated = (int)((System.nanoTime() - this.hasDestroyedTooFastStartTime) / (50L * 1000L * 1000L));
+        int tickDiff = this.gameTicks - this.delayedTickStart;
+        return (com.destroystokyo.paper.PaperConfig.lagCompensateBlockBreaking && lagCompensated > (tickDiff + 1)) ? lagCompensated : tickDiff; // add one to ensure we don't lag compensate unless we need to
+    }
+    // Paper end
+
     public ServerPlayerGameMode(ServerPlayer player) {
         this.gameModeForPlayer = GameType.DEFAULT_MODE;
         this.destroyPos = BlockPos.ZERO;
@@ -130,7 +144,7 @@ public class ServerPlayerGameMode {
             if (iblockdata == null || iblockdata.isAir()) { // Paper
                 this.hasDelayedDestroy = false;
             } else {
-                float f = this.incrementDestroyProgress(iblockdata, this.delayedDestroyPos, this.delayedTickStart);
+                float f = this.updateBlockBreakAnimation(iblockdata, this.delayedDestroyPos, this.getTimeDiggingTooFastLagCompensate()); // Paper - lag compensate destroying blocks
 
                 if (f >= 1.0F) {
                     this.hasDelayedDestroy = false;
@@ -150,7 +164,7 @@ public class ServerPlayerGameMode {
                 this.lastSentState = -1;
                 this.isDestroyingBlock = false;
             } else {
-                this.incrementDestroyProgress(iblockdata, this.destroyPos, this.destroyProgressStart);
+                this.updateBlockBreakAnimation(iblockdata, this.destroyPos, this.getTimeDiggingLagCompensate()); // Paper - lag compensate destroying
             }
         }
 
@@ -158,6 +172,12 @@ public class ServerPlayerGameMode {
 
     private float incrementDestroyProgress(BlockState state, BlockPos pos, int i) {
         int j = this.gameTicks - i;
+        // Paper start - change i (startTime) to totalTime
+        return this.updateBlockBreakAnimation(state, pos, j);
+    }
+    private float updateBlockBreakAnimation(BlockState state, BlockPos pos, int totalTime) {
+        int j = totalTime;
+        // Paper end
         float f = state.getDestroyProgress(this.player, this.player.level, pos) * (float) (j + 1);
         int k = (int) (f * 10.0F);
 
@@ -234,7 +254,7 @@ public class ServerPlayerGameMode {
                     return;
                 }
 
-                this.destroyProgressStart = this.gameTicks;
+                this.destroyProgressStart = this.gameTicks; this.lastDigTime = System.nanoTime(); // Paper - lag compensate block breaking
                 float f = 1.0F;
 
                 iblockdata1 = this.level.getBlockState(pos);
@@ -287,12 +307,12 @@ public class ServerPlayerGameMode {
                     int j = (int) (f * 10.0F);
 
                     this.level.destroyBlockProgress(this.player.getId(), pos, j);
-                    this.player.connection.send(new ClientboundBlockBreakAckPacket(pos, this.level.getBlockState(pos), action, true, "actual start of destroying"));
+                    if (!com.destroystokyo.paper.PaperConfig.lagCompensateBlockBreaking) this.player.connection.send(new ClientboundBlockBreakAckPacket(pos, this.level.getBlockState(pos), action, true, "actual start of destroying"));
                     this.lastSentState = j;
                 }
             } else if (action == ServerboundPlayerActionPacket.Action.STOP_DESTROY_BLOCK) {
                 if (pos.equals(this.destroyPos)) {
-                    int k = this.gameTicks - this.destroyProgressStart;
+                    int k = this.getTimeDiggingLagCompensate(); // Paper - lag compensate block breaking
 
                     iblockdata1 = this.level.getBlockState(pos);
                     if (!iblockdata1.isAir()) {
@@ -309,12 +329,18 @@ public class ServerPlayerGameMode {
                             this.isDestroyingBlock = false;
                             this.hasDelayedDestroy = true;
                             this.delayedDestroyPos = pos;
-                            this.delayedTickStart = this.destroyProgressStart;
+                            this.delayedTickStart = this.destroyProgressStart; this.hasDestroyedTooFastStartTime = this.lastDigTime; // Paper - lag compensate block breaking
                         }
                     }
                 }
 
+                // Paper start - this can cause clients on a lagging server to think they're not currently destroying a block
+                if (com.destroystokyo.paper.PaperConfig.lagCompensateBlockBreaking) {
+                    this.player.connection.send(new ClientboundBlockUpdatePacket(this.level, pos));
+                } else {
                 this.player.connection.send(new ClientboundBlockBreakAckPacket(pos, this.level.getBlockState(pos), action, true, "stopped destroying"));
+                }
+                // Paper end - this can cause clients on a lagging server to think they're not currently destroying a block
             } else if (action == ServerboundPlayerActionPacket.Action.ABORT_DESTROY_BLOCK) {
                 this.isDestroyingBlock = false;
                 if (!Objects.equals(this.destroyPos, pos) && !BlockPos.ZERO.equals(this.destroyPos)) {
@@ -326,7 +352,7 @@ public class ServerPlayerGameMode {
                 }
 
                 this.level.destroyBlockProgress(this.player.getId(), pos, -1);
-                this.player.connection.send(new ClientboundBlockBreakAckPacket(pos, this.level.getBlockState(pos), action, true, "aborted destroying"));
+                if (!com.destroystokyo.paper.PaperConfig.lagCompensateBlockBreaking) this.player.connection.send(new ClientboundBlockBreakAckPacket(pos, this.level.getBlockState(pos), action, true, "aborted destroying")); // Paper - this can cause clients on a lagging server to think they stopped destroying a block they're currently destroying
 
                 CraftEventFactory.callBlockDamageAbortEvent(this.player, pos, this.player.getInventory().getSelected()); // CraftBukkit
             }
@@ -338,7 +364,13 @@ public class ServerPlayerGameMode {
 
     public void destroyAndAck(BlockPos pos, ServerboundPlayerActionPacket.Action action, String reason) {
         if (this.destroyBlock(pos)) {
+            // Paper start - this can cause clients on a lagging server to think they're not currently destroying a block
+            if (com.destroystokyo.paper.PaperConfig.lagCompensateBlockBreaking) {
+                this.player.connection.send(new ClientboundBlockUpdatePacket(this.level, pos));
+            } else {
             this.player.connection.send(new ClientboundBlockBreakAckPacket(pos, this.level.getBlockState(pos), action, true, reason));
+            }
+            // Paper end - this can cause clients on a lagging server to think they're not currently destroying a block
         } else {
             this.player.connection.send(new ClientboundBlockUpdatePacket(this.level, pos)); // CraftBukkit - SPIGOT-5196
         }