Get location in front of player

How can I get the location just in front of the player? Ideally I'd want to make sure nothing occupies the space as well.

From past experience I'm guessing it has something to do with getting the player camera and the forward vector, but I'm not sure exactly.

Solution

Do something like this, trace around and see what you get a hit on

Jump to solution

Robb•9/27/24, 6:54 PM

look at how TFIT does it for the purposes of the overlay

Robb•9/27/24, 6:54 PM

I do a raycast with a fixed distance from the eyes

SirDigbyOP•9/27/24, 6:55 PM

I don't really need to do a raycast or trace, I'm not trying to target anything

Robb•9/27/24, 6:56 PM

I think the math function that goes into it is the same

D4rk•9/27/24, 6:56 PM

The float scalar is the distance in front of the player

D4rk•9/27/24, 6:57 PM

sorry, missed a piece

SirDigbyOP•9/27/24, 6:57 PM

And that multiplier is the distance? So 500 for 500cm?

D4rk•9/27/24, 6:57 PM

yup

SirDigbyOP•9/27/24, 6:58 PM

Neat

SirDigbyOP•9/27/24, 6:59 PM

Works perfectly

D4rk•9/27/24, 7:00 PM

@Robb (Mods don't work on 1.0) do you think its a good idea to add code snippets like this to the docs, like maybe one page with images and a brief description of what they do?

SirDigbyOP•9/27/24, 7:00 PM

Hmm, now to figure out how to make sure that the spot isn't underground

SSirDigby Hmm, now to figure out how to make sure that the spot isn't underground

D4rk•9/27/24, 7:01 PM

The only way I know of to do this is to trace, and cast hit actor to landscape proxy

DD4rk @Robb (Mods don't work on 1.0) do you think its a good idea to add code snippets...

Robb•9/27/24, 7:01 PM

quite possibly, not sure what the best home for it would be. and it always ends up changing depending on the use case

D4rk•9/27/24, 7:02 PM

yeah, but maybe just for UE specific stuff that gets asked occasionally and would probably never change

SirDigbyOP•9/27/24, 7:02 PM

That's what answer overflow will end up being, right?

DD4rk The only way I know of to do this is to trace, and cast hit actor to landscape p...

SirDigbyOP•9/27/24, 7:09 PM

That doesn't seem to be working when I hit a cliff actor. Are there any other outliers?

SSirDigby That's what answer overflow will end up being, right?

Robb•9/27/24, 7:11 PM

good point. but a docs page should point out that AO exists, and there may still be merit in a "greatest hits" of it

D4rk•9/27/24, 7:11 PM

For hitting the landscape I think its actually LandscapeStreamingProxy, the cliffs are FGCliffActor, but some rocks might be StaticMeshActor or InstancedFoliageActor

Solution

D4rk•9/27/24, 7:14 PM

Do something like this, trace around and see what you get a hit on

SirDigbyOP•9/27/24, 7:19 PM

That's what I ended up doing

DD4rk Do something like this, trace around and see what you get a hit on

Robb•9/27/24, 7:22 PM

why the Visibility channel? I only have guesses about the purpose of most of the channels but I haven't seen that one before

D4rk•9/27/24, 7:23 PM

https://www.unrealengine.com/en-US/blog/collision-filtering

Unreal Engine

Collision Filtering in Unreal Engine 4

Choosing what collides is obviously very important, but it can be tricky, and it’s a problem that we have spent quite a while discussing while developing UE4. The system we have can seem a little complex at first, but it is very powerful and consistent, so I wanted to give a little background on how we arrived at it. We’ll talk about the differe...

D4rk•9/27/24, 7:24 PM

Its the default setting for trace and I didn't change it for the example, but you can get different results by tracing in different channels.

DD4rk sorry, missed a piece

Archengius•9/27/24, 8:04 PM

that is not the correct way to trace from player camera

Archengius•9/27/24, 8:05 PM

it does not account for any camera modifiers or view mode specific modifications to the view

Archengius•9/27/24, 8:07 PM

you want APlayerController::GetPlayerViewPoint

Archengius•9/27/24, 8:10 PM

which does not seem to be BP exposed for some reason, so what you can do instead is Player Controller -> Player Camera Manager -> Get Camera Location/Rotation

Archengius•9/27/24, 8:11 PM

you can also hijack the fact that GetStreamingSourceLocationAndRotationGetStreamingSourceLocationAndRotation just returns the same value as APlayerController::GetPlayerViewPoint and call that function instead

D4rk•9/27/24, 8:17 PM

Thanks, I have noticed that the trace is a little bit off sometimes, this seems to explain it. I'll update all my functions to use this method instead.

Archengius•9/27/24, 8:18 PM

just keep in mind that this location is a few frames behind if you try to check it on the server for a remote client

Archengius•9/27/24, 8:19 PM

if you go through portals it can be behind A LOT

Archengius•9/27/24, 8:19 PM

actually resulted in some bugs in the base game

Robb•9/27/24, 8:20 PM

any suggestions for coping with and/or detecting that it's behind?

Archengius•9/27/24, 8:32 PM

do not expect player camera position to ever be accurate or even representative of the client sided position

Archengius•9/27/24, 8:32 PM

do tracing and any related activities on the client

Archengius•9/27/24, 8:32 PM

only pass resulting actions to the server

Archengius•9/27/24, 8:33 PM

example: xeno zapper actually does camera tracing, overlap detection and VFX on the client

Archengius•9/27/24, 8:33 PM

the only thing that server gets is a list of actors that should get damaged and a location of the impact

Robb•9/27/24, 8:34 PM

so a client side mod could make it possible to hit any loaded creature if it wanted to? not a balance problem for this game, just checking understanding

Archengius•9/27/24, 8:34 PM

yes

Archengius•9/27/24, 8:35 PM

I generally also follow the assumption that the client cannot be trusted, so xeno basher also does server sided timing and validation

Archengius•9/27/24, 8:35 PM

so it will refuse to hit anything more frequently than you can swing it, with a small window to compensate for ping

Get location in front of player

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