ARKit-放置物体而不触摸屏幕

Question

使用ARKit，我可以点击表面将3D对象放置在此处。 我也可以移动手指，从而使物体沿表面移动。

如何使物体自动出现并粘在相机前面的表面上，而无需触摸屏幕？

这是通过手指点击放置3D对象的示例脚本：

using System;
using System.Collections.Generic;

namespace UnityEngine.XR.iOS
{
    public class UnityARHitTestExample : MonoBehaviour
    {
        public Transform m_HitTransform;

        bool HitTestWithResultType (ARPoint point, ARHitTestResultType resultTypes)
        {
            List<ARHitTestResult> hitResults = UnityARSessionNativeInterface.GetARSessionNativeInterface ().HitTest (point, resultTypes);
            if (hitResults.Count > 0) {
                foreach (var hitResult in hitResults) {
                    Debug.Log ("Got hit!");
                    m_HitTransform.position = UnityARMatrixOps.GetPosition (hitResult.worldTransform);
                    m_HitTransform.rotation = UnityARMatrixOps.GetRotation (hitResult.worldTransform);
                    Debug.Log (string.Format ("x:{0:0.######} y:{1:0.######} z:{2:0.######}", m_HitTransform.position.x, m_HitTransform.position.y, m_HitTransform.position.z));
                    return true;
                }
            }
            return false;
        }

        // Update is called once per frame
        void Update () {
            if (Input.touchCount > 0 && m_HitTransform != null)
            {
                var touch = Input.GetTouch(0);
                if (touch.phase == TouchPhase.Began || touch.phase == TouchPhase.Moved)
                {
                    var screenPosition = Camera.main.ScreenToViewportPoint(touch.position);
                    ARPoint point = new ARPoint {
                        x = screenPosition.x,
                        y = screenPosition.y
                    };

                    // prioritize reults types
                    ARHitTestResultType[] resultTypes = {
                        ARHitTestResultType.ARHitTestResultTypeExistingPlaneUsingExtent, 
                        // if you want to use infinite planes use this:
                        //ARHitTestResultType.ARHitTestResultTypeExistingPlane,
                        ARHitTestResultType.ARHitTestResultTypeHorizontalPlane, 
                        ARHitTestResultType.ARHitTestResultTypeFeaturePoint
                    }; 

                    foreach (ARHitTestResultType resultType in resultTypes)
                    {
                        if (HitTestWithResultType (point, resultType))
                        {
                            return;
                        }
                    }
                }
            }
        }


    }
}

Answer 1

我在Objective-C中做了类似的事情，因此希望可以为您提供统一的示例。

我的逻辑基本上是，使用轻敲放置对象是基于hitTest函数的，从触摸位置检索到的是提供给它的点。 因此，我只是在屏幕中央以编程方式创建了CGPoint，并在此点运行了hitTest函数。 它是否已挂接到计时器，并且当命中返回对象时，已在其中添加了对象。

CGPoint point = CGPointMake(self.sceneView.frame.size.width / 2, self.sceneView.frame.size.height / 2); //Get a point at the middle of the screen
NSArray <ARHitTestResult *> *hitResults = [_sceneView hitTest:point types:ARHitTestResultTypeFeaturePoint]; //Try to do a AR Hit Test on this point
if ([hitResults count] != 0) { //If have any results
    //Perform desired operation
}