Fixed rubberbanding when flying in multiplayer

src/main/java/com/minelittlepony/unicopia/entity/MotionChecker.java

@@ -0,0 +1,5 @@
+package com.minelittlepony.unicopia.entity;
+
+public interface MotionChecker {
+    void setPreventMotionChecks(boolean enabled);
+}

src/main/java/com/minelittlepony/unicopia/mixin/MixinLivingEntity.java

@@ -20,9 +20,9 @@ import com.minelittlepony.unicopia.entity.PonyContainer;
 import com.minelittlepony.unicopia.entity.behaviour.Disguise;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.entity.Equine;
+import com.minelittlepony.unicopia.entity.ItemWielder;
 import com.minelittlepony.unicopia.entity.Jumper;
 import com.minelittlepony.unicopia.entity.Leaner;
-import com.minelittlepony.unicopia.entity.ItemWielder;
 
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.LivingEntity;

src/main/java/com/minelittlepony/unicopia/mixin/MixinServerPlayNetworkHandler.java

@@ -0,0 +1,53 @@
+package com.minelittlepony.unicopia.mixin;
+
+import org.spongepowered.asm.mixin.Mixin;
+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 com.minelittlepony.unicopia.entity.MotionChecker;
+import com.minelittlepony.unicopia.entity.player.Pony;
+
+import net.minecraft.network.NetworkThreadUtils;
+import net.minecraft.network.listener.ServerPlayPacketListener;
+import net.minecraft.network.packet.c2s.play.PlayerMoveC2SPacket;
+import net.minecraft.server.network.ServerPlayNetworkHandler;
+import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.server.world.EntityTrackingListener;
+
+@Mixin(ServerPlayNetworkHandler.class)
+abstract class MixinServerPlayNetworkHandler implements EntityTrackingListener, ServerPlayPacketListener {
+    @Shadow private boolean floating;
+    @Shadow private int floatingTicks;
+
+    private boolean flyingSurvival;
+    private boolean prevMotionChecks;
+
+    @Inject(method = "onPlayerMove(Lnet/minecraft/network/packet/c2s/play/PlayerMoveC2SPacket;)V", at = @At("HEAD"))
+    private void beforePlayerMove(PlayerMoveC2SPacket packet, CallbackInfo info) {
+        ServerPlayerEntity player = ((ServerPlayNetworkHandler)(Object)this).player;
+        NetworkThreadUtils.forceMainThread(packet, this, player.getServerWorld());
+        flyingSurvival = Pony.of(player).getPhysics().isFlyingSurvival;
+
+        if (flyingSurvival) {
+            setPreventMotionChecks(true);
+        }
+    }
+
+    @Inject(method = "onPlayerMove(Lnet/minecraft/network/packet/c2s/play/PlayerMoveC2SPacket;)V", at = @At("RETURN"))
+    private void afterPlayerMove(PlayerMoveC2SPacket packet, CallbackInfo info) {
+        if (flyingSurvival) {
+            setPreventMotionChecks(prevMotionChecks);
+        }
+    }
+
+    private void setPreventMotionChecks(boolean motionChecks) {
+        ServerPlayerEntity player = ((ServerPlayNetworkHandler)(Object)this).player;
+        prevMotionChecks = player.isInTeleportationState();
+        ((MotionChecker)player).setPreventMotionChecks(motionChecks);
+        player.fallDistance = 0;
+        floating = false;
+        floatingTicks = 0;
+    }
+}

src/main/java/com/minelittlepony/unicopia/mixin/MixinServerPlayerEntity.java

@@ -1,11 +1,13 @@
 package com.minelittlepony.unicopia.mixin;
 
 import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 import com.minelittlepony.unicopia.entity.PonyContainer;
+import com.minelittlepony.unicopia.entity.MotionChecker;
 import com.minelittlepony.unicopia.entity.player.Pony;
 
 import net.minecraft.entity.player.PlayerEntity;
@@ -13,12 +15,17 @@ import net.minecraft.screen.ScreenHandlerListener;
 import net.minecraft.server.network.ServerPlayerEntity;
 
 @Mixin(ServerPlayerEntity.class)
-abstract class MixinServerPlayerEntity extends PlayerEntity implements ScreenHandlerListener, PonyContainer<Pony> {
+abstract class MixinServerPlayerEntity extends PlayerEntity implements ScreenHandlerListener, PonyContainer<Pony>, MotionChecker {
     MixinServerPlayerEntity() {super(null, null, 0, null);}
 
+    @Override
+    @Accessor("inTeleportationState")
+    public abstract void setPreventMotionChecks(boolean enabled);
+
     @SuppressWarnings("unchecked")
     @Inject(method = "copyFrom(Lnet/minecraft/server/network/ServerPlayerEntity;Z)V", at = @At("HEAD"))
     private void onCopyFrom(ServerPlayerEntity oldPlayer, boolean alive, CallbackInfo info) {
         get().copyFrom(((PonyContainer<Pony>)oldPlayer).get());
     }
+
 }

src/main/resources/unicopia.mixin.json

@@ -23,6 +23,7 @@
     "MixinPlayerEntity",
     "MixinProjectileEntity",
     "MixinServerPlayerEntity",
+    "MixinServerPlayNetworkHandler",
     "MixinServerWorld",
     "MixinSheepEntity",
     "MixinShulkerEntity",