Unity XR realizes interaction (grasping, moving, rotating, transmitting, shooting) -pico

Unity XR Implement interaction （ Grab , Move rotation , delivery , Shooting ）

Preface

Unity XR Provides XR Interaction Toolkit The interactive toolkit is directly in Package Manager Install in / Update can , Simple interaction requirements can be realized 0 Code , Just attach the corresponding script to the handle and object . This demo uses the latest 2.1.0 preview edition , If the version is lower, some scripts may not be available , Please update to the latest version as far as possible .

This demonstration uses Pico XR SDK, In the import SDK Then they will carry one by themselves XR Interaction Toolkit Of 0.9 edition , Please be sure to start from Package Manager Update in , Otherwise, the subsequent options will be greatly different .

PS: After updating to the new version , Many scripts are available in new versions Action-based The way , And the old version Device-based, This blog will start with Device-based Explain , About Unity Use of new version input system , The author will focus on in the next article .

One 、 Creation of handle

• Ray Interactor： A handle template object with rays will be created
• Direct Interactor： A handle template object without rays will be created
• XR Origin(VR): Suggest , Will directly create VR The camera + Two ray handle objects , It is more convenient and can be changed directly on this basis in the future .

Two 、 Grab of handle

1. XR DirectController The handle grabs directly

• Interaction Manager: Interaction management class — The key , Usually with XR Origin Created together , Generally, the creation handle will be directly attached , If there is no mount, you need to go Hireachy Mount the panel manually .
• Interaction Layer Mask : On grasping objects XR Grab Interactable The script also has an attribute of the same name , Only objects Layer Mask Only when it matches the handle can it be grabbed .
• Attack Transform : Grab position of handle , At the same time, the object can also set the grab position , When grasping, the grasping position of the handle will be the same as that of the object , You can configure the appropriate location according to the specific needs .
• Colliding body ： If not using template configuration , It is easy to forget this component by mounting the script by yourself , Only when there is a collision body in direct grasp can we detect the grasping object and carry out the grasping operation , Rays do not need to collide , Just radiographic testing .

2. XR Ray Interactor Handle ray grab

Handle ray capture generally uses the default settings to attract the hit object onto the handle , There is no need to add colliders , Such as Layer Mask And other properties are consistent with the above , I won't repeat .

3. XR Grab Interactable Grab objects

• Interaction Manager/LayerMask/Attack Transform, Several common attributes are XR DirectController Described in , I won't repeat
• Collider： Must have , Grabbing is achieved by collider detection
• Rigibody： Recommended ownership ,VR The effects of grabbing and throwing of grasping objects in the scene are based on their own rigid bodies .
• Interactable Events： It provides a callback for grabbing a series of events , Such as the callback of grabbing objects , Release the callback of the object , Grab the object and press Trigger Key callback and so on , The subsequent shooting function is based on this .

3、 ... and 、 The handle rocker controls movement and rotation

Use the left joystick to control continuous rotation , Take the continuous movement of the right-hand rocker control as an example

According to the picture above , stay XR Origin Add Locomotion System,Continous Turn Provider And so on , Then configure according to the arrow in the above figure .

• Note that these scripts do not have to be placed in XR Origin On the body , Anywhere, but properties must be configured , Put it in XR Origin Easy to manage .
• Continous It's a script that keeps moving and rotating , Controlled by the rocker of the handle , If you want to rotate or move a distance at a time / angle , It can be used Snap Turn/Move, In the lower version of XR Some scripts may not be supported in the interactive package .

Four 、 Handle ray transmission

1. Basic function version

• Basic transmission management class Teleportion Provider You have to add , It is recommended to add them together in XR Origin in

• Handle in charge of transmission , The first must be XR Ray Interactor Ray control , Generally speaking, parabola will be used , Or Bessel curve , About its related parameters, we can search the knowledge of Bezier curve ,Sample Frequency Sampling points will directly affect the smoothness of the curve .

• Reticle It is the indicator after the ray hits the target , It is very suitable as an indicator of the transmission target point , If there is no suitable indicator, it can be simply demonstrated with a sphere .

In addition to the setting of the ray handle , You also need to add Teleportation Area Script （ If you want to only transmit to a fixed point, you can use Anchor, Use consistent ）, Then, when the ray detects the ground that can be transmitted, the ray will turn green , Press by default Trigger Key to achieve transmission .

2. premium

Problems to be improved

1. Only mount the default script , Sometimes it can't meet the needs to a great extent , For example, the transfer function of the general handle will not always have a curve to select the position , We would like it to have a curvilinear rotation position when pressing a key or pushing the rocker , Transfer when releasing the key or rocker .

2. The handle responsible for transmission cannot be mounted at the same time Ray Interactor and Direct Interactor in other words , We can't just mount the script to realize that the handle is usually responsible for direct grabbing , When you want to transmit, you can get the ray selection position transmission .

Aiming at problems 1,2 Scene , The author is usually responsible for direct grabbing with the left handle , Press down A Take the ray selection position transmission of the key as an example , Give a solution .

The basic idea

1. Create two left handle objects , A mount Direct Interactor Responsible for daily grabbing , A mount Ray Interactor Responsible for transmitting .
2. Usual Ray Interactor Scripts will be disabled , Only when you press A Key can be enabled to select the position , When released A The post key code controls the transmission request , Disable the script indicator and so on .

About pressing and lifting the handle keys Down and Up event , If you use an old input system, you can refer to this article https://blog.csdn.net/Q540670228/article/details/123139150, The process of starting and disabling scripts is relatively simple , Only the code that initiates the transmission request when lifting the key is given below .

    // The acquisition of the delivery manager script is omitted 
	public TeleportationProvider provider;
	// Handle in charge of transmission XRRayInteractor Script , The acquisition process is omitted 
	public XRRayInteractor teleportRayInteractor;
	private void LeftAXButtonUpHandler()
    {
    
        // Ray information 
        RaycastHit rayInfo;
        // Judge whether the target point is effective  1. Whether to hit the target  2. Whether they have Teleportation Components 
        bool isValid = teleportRayInteractor.TryGetCurrent3DRaycastHit(out rayInfo);
        isValid = isValid && rayInfo.collider != null &&
                  (rayInfo.collider.GetComponent<TeleportationArea>() != null ||
                   rayInfo.collider.GetComponent<TeleportationAnchor>() != null);
        if (isValid)
        {
    
            // Create a transmission demand and take the location where the ray hits as the destination , Submitted to the provider Transmission queue in .
            TeleportRequest request = new TeleportRequest();
            request.destinationPosition = rayInfo.point;
            provider.QueueTeleportRequest(request);
        }
        
        // Disable related scripts and indicators 
        teleportRayInteractor.enabled = false;
        teleportRayInteractor.GetComponent<XRInteractorLineVisual>().reticle?.SetActive(false);
    }

5、 ... and 、 Handle control shooting

stay VR The game often has the function of picking up guns and shooting , The general design difficulties are

1. Judge whether the object is grabbed , By which handle
2. Whether the handle that grabs this object is pressed Trigger key

stay XR Grab Interactable The script has provided a very intimate event , The trigger conditions are the above two . Use as follows

private XRGrabInteractable grab;
private void Awake()
{
    grab = GetComponent<XRGrabInteractable>();
    // by activated Add a listening function to the event 
    grab.activated.AddListener(GrabHandler);
}

private void GrabHandler(ActivateEventArgs a)
{
	// When the gun is grabbed and pressed Trigger Callback this method after , Trigger firing method .
    Shoot();
}