Unity: VR Head Blocking (Steam VR v2)

Fade color can be changed or disabled to produce a pure wall push back effect on impact.



VRHeadBlocking.cs:

// VR Head Blocking Script (Synaptic Response)
// For use with SteamVR Unity Plugin v2
// Attach to Player -> FollowHead -> HeadCollider and set Tag to "Player"
// Initial Implementation: Scott Lupton (04.18.2020)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Valve.VR;

public class VRHeadBlocking : MonoBehaviour
{     
    public GameObject player;    
    [SerializeField] bool fadeEnabled = true;
    [SerializeField] Color fadeColor = Color.black;

    private int layerMask;
    private Collider[] objs = new Collider[10];
    private Vector3 prevHeadPos;
    private int fadeState = 0;
    private float fadeDuration = .5f;
    private float internalFadeTimer = 0f;    
    private float backupCap = .2f;
    
    private void Start()
    {
        layerMask = 1 << 8;
        layerMask = ~layerMask;

        prevHeadPos = transform.position;                    

        FadeToColor();
        Invoke("FadeFromColor", fadeDuration);
    }

    private void FadeToColor()
    {        
        SteamVR_Fade.Start(Color.clear, 0f);
        SteamVR_Fade.Start(fadeColor, fadeDuration);
    }

    private void FadeFromColor()
    {        
        SteamVR_Fade.Start(fadeColor, 0f);
        SteamVR_Fade.Start(Color.clear, fadeDuration);
    }

    private int DetectHit(Vector3 loc)
    {
            int hits = 0;
            int size = Physics.OverlapSphereNonAlloc(loc, backupCap, objs, layerMask, QueryTriggerInteraction.Ignore);
            for (int i = 0 ; i < size; i++) {
                if (objs[i].tag != "Player") {                    
                    hits++;
                }                
            }
            return hits;
    }
    
    public void Update()
    {        
        if (player != null) {            
        
            // Fade state control
            if (fadeEnabled) {
                internalFadeTimer -= Time.deltaTime;
                if (fadeState == 1 && internalFadeTimer <= 0) {
                    internalFadeTimer = fadeDuration;
                    FadeFromColor();
                    fadeState = 2;
                }
                else if (fadeState == 2 && internalFadeTimer <= 0) fadeState = 0;         
            }
                        
            int hits = DetectHit(transform.position);
            
            // No collision
            if (hits == 0) prevHeadPos = transform.position;                           
                
            // Collision
            else {            

                // Player pushback
                bool notCapped = true;       
                Vector3 headDiff = transform.position - prevHeadPos;
                if (Mathf.Abs(headDiff.x) > backupCap) {
                    if (headDiff.x > 0) headDiff.x = backupCap;
                    else headDiff.x = backupCap * -1;
                    notCapped = false;
                }
                if (Mathf.Abs(headDiff.z) > backupCap) {
                    if (headDiff.z > 0) headDiff.z = backupCap;
                    else headDiff.z = backupCap * -1;
                    notCapped = false;
                }                
                Vector3 adjHeadPos = new Vector3(player.transform.position.x-headDiff.x,
                                                 player.transform.position.y,
                                                 player.transform.position.z-headDiff.z);
                player.transform.SetPositionAndRotation(adjHeadPos, player.transform.rotation);

                // Trigger fade if enabled
                if (fadeEnabled && notCapped && fadeState == 0) {                    
                    internalFadeTimer = fadeDuration;
                    FadeToColor(); 
                    fadeState = 1;                    
                }
            }
        }
    }
}