Momentum for a First Person Controller in Godot 4

CryptoMares

My First Person Controller (CharacterBody3D) currently has no momentum at all. By the way, I measure my movement speed in the debug panel (hotkey ~) with velocity.length() and when I get pushed by one of the platforms (see the video), my speed stays at 0 while I’m being pushed, which isn’t how it supposed to be. What would be the best way to add a momentum/inertia feature and measure my current speed at all times?

Demo:

Source:
https://github.com/CryptoMares/FPS-Player-Controller

Thanks!

Jesusemora

CryptoMares CharacterBody is KINEMATIC, it is not moved by physics, it is moved by code.
if you want the player to react to physics you need to use a rigidbody.

if you want to measure the speed of a CharacterBody, the best way is to store the global_position in a variable and compare it with the global_position:

var last_pos : Vector3
var curr_speed : float = 0.0

func _ready():
     last_pos = global_position

func _physics_process(delta):
     curr_speed = last_pos.distance_to(global_position)
     last_pos = global_position

I believe you can divide curr_speed by delta to get the speed per second:
curr_speed = last_pos.distance_to(global_position) / delta

CryptoMares

Jesusemora Is there any way to add this kind of behavior to a Kinematic body? Rigid body will introduce a bunch of unwanted behaviours, that will need to be mitigated, I believe. Am I wrong?

Megalomaniak

insert something about tweens and interpolations here

CryptoMares

Megalomaniak I would love to learn how to use tweens for stuff like this. I would like to tween most of my variables, I don't know how though, I'm a newbie.

kuligs2

why not lerp?

CryptoMares

kuligs2 Well, lerp is linear and I would like a curve. Ideally, a custom curve that I can control precisely.

axolotl

You could try to do something physics-like: measure your velocity, and then if no input and touching the ground: change it progressively to zero. If not touching the ground: change it progressively to straight down.

CryptoMares

axolotl That's too advanced for me to figure out on my own right now, unfortunately 🙂

wabbit

I've been working on an answer for a few days. This has been something I've wanted and tried to do for a while now, so I'm happy that my asset was just accepted to the AssetLib! It's called Rigid Character Body 3D, if you're using Godot 4.2 or later you can take a look at it. It's not the greatest thing ever but I think it does a good enough job to get you going on this.
It extends RigidBody3D and adds movement forces and drag which creates a simple and configurable character controller.

kuligs2

wabbit its under GPLv3 licence 🙁

CryptoMares

wabbit That's awesome, thank you! However it's not exactly what I'm would like to achieve, I would like something of an imitation of momentum added specifically to a Kinematic Character Controller.

wabbit

kuligs2 changed it to MIT.

kuligs2

wabbit why? 😃 GPL means that if you use it in your project, the rest of your project has to be published under gpl aswell.. and other stuff.. idk.. but ok 😃