From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Caleb Bassham Date: Fri, 28 Sep 2018 02:32:19 -0500 Subject: [PATCH] Call player spectator target events and improve implementation Use a proper teleport for teleporting to entities in different worlds. Implementation improvements authored by Spottedleaf Validate that the target entity is valid and deny spectate requests from frozen players. Also, make sure the entity is spawned to the client before sending the camera packet. If the entity isn't spawned clientside when it receives the camera packet, then the client will not spectate the target entity. Co-authored-by: Spottedleaf diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java index 645012ea3590a46773e2bb14e9cafd9e3c695fd4..cb55e38b22330dbc542003841e8140eb6bee01bf 100644 --- a/src/main/java/net/minecraft/server/level/ServerPlayer.java +++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java @@ -1876,14 +1876,58 @@ public class ServerPlayer extends Player { } public void setCamera(@Nullable Entity entity) { + // Paper start - Add PlayerStartSpectatingEntityEvent and PlayerStopSpectatingEntity Event and improve implementation Entity entity1 = this.getCamera(); - this.camera = (Entity) (entity == null ? this : entity); - if (entity1 != this.camera) { - this.connection.send(new ClientboundSetCameraPacket(this.camera)); - this.connection.teleport(this.camera.getX(), this.camera.getY(), this.camera.getZ(), this.getYRot(), this.getXRot(), TeleportCause.SPECTATE); // CraftBukkit + if (entity == null) { + entity = this; + } + + if (entity1 == entity) return; // new spec target is the current spec target + + if (entity == this) { + com.destroystokyo.paper.event.player.PlayerStopSpectatingEntityEvent playerStopSpectatingEntityEvent = new com.destroystokyo.paper.event.player.PlayerStopSpectatingEntityEvent(this.getBukkitEntity(), entity1.getBukkitEntity()); + + if (!playerStopSpectatingEntityEvent.callEvent()) { + return; + } + } else { + com.destroystokyo.paper.event.player.PlayerStartSpectatingEntityEvent playerStartSpectatingEntityEvent = new com.destroystokyo.paper.event.player.PlayerStartSpectatingEntityEvent(this.getBukkitEntity(), entity1.getBukkitEntity(), entity.getBukkitEntity()); + + if (!playerStartSpectatingEntityEvent.callEvent()) { + return; + } + } + // Validate + if (entity != this) { + if (entity.isRemoved() || !entity.valid || entity.level == null) { + MinecraftServer.LOGGER.info("Blocking player " + this + " from spectating invalid entity " + entity); + return; + } + if (this.isImmobile()) { + // use debug: clients might maliciously spam this + MinecraftServer.LOGGER.debug("Blocking frozen player " + this + " from spectating entity " + entity); + return; + } } + this.camera = entity; // only set after validating state + + if (entity != this) { + // Make sure we're in the right place + this.ejectPassengers(); // teleport can fail if we have passengers... + this.getBukkitEntity().teleport(new Location(entity.getCommandSenderWorld().getWorld(), entity.getX(), entity.getY(), entity.getZ(), this.getYRot(), this.getXRot()), TeleportCause.SPECTATE); // Correctly handle cross-world entities from api calls by using CB teleport + + // Make sure we're tracking the entity before sending + ChunkMap.TrackedEntity tracker = ((ServerLevel)entity.level).getChunkSource().chunkMap.entityMap.get(entity.getId()); + if (tracker != null) { // dumb plugins... + tracker.updatePlayer(this); + } + } else { + this.connection.teleport(this.camera.getX(), this.camera.getY(), this.camera.getZ(), this.getYRot(), this.getXRot(), TeleportCause.SPECTATE); // CraftBukkit + } + this.connection.send(new ClientboundSetCameraPacket(entity)); + // Paper end } @Override