Lenga Engine — Build Games with Modern PHP

Use it when a body should slide, travel, or be driven along a single line instead of moving freely in every direction.

Good Fits

SliderJoint2D is useful for:

elevators
pistons
push/pull rails
moving mechanical platforms

Scene Setup

Add Rigidbody2D to the moving body.
Add SliderJoint2D.
Assign Connected Body if needed.
Set the Axis.
Enable limits if the body should only travel within a range.
Enable the motor if the body should actively move itself along that axis.

Scene View Helps Here

SliderJoint2D is easiest to tune visually.

Use the Scene view to:

place the anchors
drag the axis direction
verify the travel lane before pressing play

That is usually faster than trying to guess a good axis from raw numbers alone.

Use Limits for Bounded Travel

Turn on Use Limits when the body should only move inside a travel window.

Then tune:

Lower Translation
Upper Translation

This is the normal setup for elevators, trap rails, and puzzle sliders.

Use the Motor for Powered Travel

Turn on Use Motor when the joint should actively push along the axis.

Then tune:

Motor Speed
Max Motor Force

Practical Example: Simple Elevator

For a simple moving elevator:

Add SliderJoint2D.
Set the axis to vertical.
Enable limits.
Give it a lower and upper travel range.
Turn on the motor and tune the speed.

That gives you a scene-authored moving platform without needing to script the whole travel path from scratch.

PHP Example

<?php

use Lenga\Engine\Core\Behaviour;
use Lenga\Engine\Core\SliderJoint2D;
use Lenga\Engine\Core\Vector3;

class ElevatorMotor extends Behaviour
{
    public function awake(): void
    {
        $joint = $this->gameObject->getComponent(SliderJoint2D::class);
        if ($joint === null) {
            return;
        }

        $joint->axis = new Vector3(0.0, 1.0, 0.0);
        $joint->useLimits = true;
        $joint->lowerTranslation = 0.0;
        $joint->upperTranslation = 6.0;
        $joint->useMotor = true;
        $joint->motorSpeed = 1.5;
        $joint->maxMotorForce = 2500.0;
    }
}

Use SliderJoint2D