When a mob jumps onto a block, it jumps very slowly, and looks too smooth. This also occurs when you hit a mob, and it bounces back very slowly, opposed to bouncing back fast like in versions before.
The only mob that seems unaffected at all by this bug is a beached squid, which, when on land, still gets knocked back quickly, and not slow like the other mobs. This leads me to believe that it has nothing to do with the game's code, but rather only the mobs' code.
It should be noticeable, but many people do not notice it as easily. A great way to notice this bug is by comparing any mob's jump/knockback speed to that of a squid, or go back to 1.7.10, test the mob speed there, and come back to 1.8. You will most definately notice the difference.
This happens regardless of mob gamerules like /doMobSpawning false. This issue is unrelated to MC-58120.
Linked issues
is duplicated by 4
relates to 2
Comments 50
No, it isn't. It's happening on every new world I create in 1.8 pre-2, regardless of domobspawning on or off. All other entities do not lag at all. This is a new issue.
I have changed the video and put annotations in there, since it is describing this bug more correctly:
http://youtu.be/Bdfs8a3UfKg
(Feel free to put the link in the description of the bug if you think it helps describe the issue.)
Thank you, Kumasasa.
I'll take a look, Walden, thanks.
EDIT Just commented on the video, the vid didn't quite show the bug correctly. It did show that old worlds seem to have excessive lag, or at least worlds with a lot of content. I suggest re-doing the video like I said in the comment.
@unknown: Ok, lets continue the discussion in the comments on the video. I am willing to do more extensive testing.
As @fyberoptic has pointed out, this bug is due to the client no longer predicting the position of entities and relying on server packets, which they ssmooth the position accross 3 ticks. There is no easy fix: one fix would, as Jeff did, revert the change made in 1.8 to client prediction: but this would bring back the stutterness caused by conflict between client prediction and server packets. Another solution, which seems more viable to me, is increasing the rate of packets sent by the server, which would eliminate the need for linear interpolation which cause the visual slowness: however, sending entity packets every tick has its own share of issues, but it could be considered for integrated servers (Singleplayer) as no real network traffic is required for packets between the server and the client.
I have tried implementing such fix on a personal mod, where I simply forced the server to send entity move packets every tick instead of using their built-in update interval, and client-side I would disable the linear interpolation and directly set the position: the result looks similar to 1.2.5 SSP mobs, minus the slight (but virtually invisible) latency between Client and Server. However, the downside of this is that a slight tick lag would cause all mob movement to stutter and be unsmooth, but at least it isn't a glaring issue.
This is MC-58120. Will happen in worlds created / openened with 14w2x / 14w3x snapshots. Delete the worlds and create a new one in 1.8