Compute difference between server and client to fix ghost blocks

src/main/java/net/smoofyuniverse/superpiston/impl/internal/InternalStructureResolver.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2018-2022 Hugo Dupanloup (Yeregorix)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.smoofyuniverse.superpiston.impl.internal;
+
+import net.minecraft.core.BlockPos;
+
+import java.util.Set;
+
+public interface InternalStructureResolver {
+
+	void resolveBlocksToRefresh();
+
+	Set<BlockPos> getBlocksToRefresh();
+}

src/main/java/net/smoofyuniverse/superpiston/mixin/block/PistonBaseBlockMixin.java

@@ -24,13 +24,20 @@
 
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
+import net.minecraft.server.level.ServerChunkCache;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.piston.PistonBaseBlock;
+import net.minecraft.world.level.block.piston.PistonStructureResolver;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.material.PushReaction;
+import net.smoofyuniverse.superpiston.impl.internal.InternalStructureResolver;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
 
 @Mixin(PistonBaseBlock.class)
 public abstract class PistonBaseBlockMixin {
@@ -44,4 +51,23 @@ public PushReaction alwaysPushNormal(BlockState stateIn, BlockState state, Level
 	public boolean alwaysPushable(BlockState state, Level level, BlockPos pos, Direction facing, boolean destroy, Direction facing2) {
 		return true;
 	}
+
+	@Redirect(method = "moveBlocks", at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/block/piston/PistonStructureResolver;resolve()Z"))
+	public boolean onMoveResolve(PistonStructureResolver resolver) {
+		if (resolver.resolve()) {
+			((InternalStructureResolver) resolver).resolveBlocksToRefresh();
+			return true;
+		}
+		return false;
+	}
+
+	@Inject(method = "moveBlocks", at = @At(value = "RETURN"), locals = LocalCapture.CAPTURE_FAILHARD)
+	public void onMoveEnd(Level level, BlockPos piston, Direction facing, boolean extending,
+						  CallbackInfoReturnable<Boolean> cir, BlockPos head, PistonStructureResolver resolver) {
+		if (level instanceof ServerLevel) {
+			ServerChunkCache cache = ((ServerLevel) level).getChunkSource();
+			for (BlockPos pos : ((InternalStructureResolver) resolver).getBlocksToRefresh())
+				cache.blockChanged(pos);
+		}
+	}
 }

src/main/java/net/smoofyuniverse/superpiston/mixin/block/PistonStructureResolverMixin.java

@@ -32,38 +32,59 @@
 import net.smoofyuniverse.superpiston.api.structure.calculator.PistonStructureCalculator;
 import net.smoofyuniverse.superpiston.impl.event.PostStructureCalculationEvent;
 import net.smoofyuniverse.superpiston.impl.event.PreStructureCalculationEvent;
+import net.smoofyuniverse.superpiston.impl.internal.InternalStructureResolver;
 import org.spongepowered.api.Sponge;
 import org.spongepowered.api.block.BlockSnapshot;
 import org.spongepowered.api.event.Cause;
 import org.spongepowered.api.util.Direction;
 import org.spongepowered.api.world.server.ServerWorld;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
-import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Mutable;
 import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 import org.spongepowered.common.util.Constants;
 import org.spongepowered.common.util.VecHelper;
 import org.spongepowered.math.vector.Vector3i;
 
+import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 @Mixin(PistonStructureResolver.class)
-public class PistonStructureResolverMixin {
-	@Shadow
+public abstract class PistonStructureResolverMixin implements InternalStructureResolver {
+	private final Set<BlockPos> toRefresh = new HashSet<>();
 	@Final
-	private Level level;
 	@Shadow
+	private Level level;
+	@Mutable
 	@Final
-	private List<BlockPos> toPush;
 	@Shadow
+	private List<BlockPos> toPush;
+	@Mutable
 	@Final
+	@Shadow
 	private List<BlockPos> toDestroy;
+	@Final
+	@Shadow
+	private net.minecraft.core.Direction pushDirection;
 
 	private Direction direction, movement;
 	private BlockSnapshot piston;
+	private boolean resolveCustom = true;
+
+	@Inject(method = "resolve", at = @At("HEAD"), cancellable = true)
+	public void onResolve(CallbackInfoReturnable<Boolean> cir) {
+		if (this.resolveCustom) {
+			SuperPistonTimings.CALCULATION.startTiming();
+			cir.setReturnValue(resolveCustom());
+			SuperPistonTimings.CALCULATION.stopTiming();
+		}
+	}
 
 	@Inject(method = "<init>", at = @At("RETURN"))
 	public void onInit(Level level, BlockPos pos, net.minecraft.core.Direction pistonDirection, boolean extending, CallbackInfo ci) {
@@ -72,21 +93,10 @@ public void onInit(Level level, BlockPos pos, net.minecraft.core.Direction pisto
 		this.movement = extending ? this.direction : this.direction.opposite();
 	}
 
-	/**
-	 * @author Yeregorix
-	 */
-	@Overwrite
-	public boolean resolve() {
-		SuperPistonTimings.CALCULATION.startTiming();
-		boolean r = calculate();
-		SuperPistonTimings.CALCULATION.stopTiming();
-
-		return r;
-	}
-
-	public boolean calculate() {
+	private boolean resolveCustom() {
 		this.toPush.clear();
 		this.toDestroy.clear();
+		this.toRefresh.clear();
 
 		Cause cause = Sponge.server().causeStackManager().currentCause();
 
@@ -127,4 +137,52 @@ public boolean calculate() {
 
 		return structure.isMoveable();
 	}
+
+	private void resolveVanilla() {
+		this.resolveCustom = false;
+		resolve();
+		this.resolveCustom = true;
+	}
+
+	@Shadow
+	public abstract boolean resolve();
+
+	@Override
+	public void resolveBlocksToRefresh() {
+		this.toRefresh.clear();
+
+		// Backup custom blocks
+		List<BlockPos> toPushCustom = this.toPush;
+		List<BlockPos> toDestroyCustom = this.toDestroy;
+		this.toPush = new ArrayList<>();
+		this.toDestroy = new ArrayList<>();
+
+		// Resolve vanilla blocks
+		this.resolveCustom = false;
+		resolve();
+		this.resolveCustom = true;
+
+		// Difference between blocks updated by the client and blocks updated by the server
+		for (BlockPos pos : this.toPush) {
+			this.toRefresh.add(pos);
+			this.toRefresh.add(pos.relative(this.pushDirection));
+		}
+		this.toRefresh.addAll(this.toDestroy);
+		for (BlockPos pos : toPushCustom) {
+			this.toRefresh.remove(pos);
+			this.toRefresh.remove(pos.relative(this.pushDirection));
+		}
+		for (BlockPos pos : toDestroyCustom) {
+			this.toRefresh.remove(pos);
+		}
+
+		// Restore custom blocks
+		this.toPush = toPushCustom;
+		this.toDestroy = toDestroyCustom;
+	}
+
+	@Override
+	public Set<BlockPos> getBlocksToRefresh() {
+		return this.toRefresh;
+	}
 }