ARKit – 使用世界射线而不是屏幕点进行光线投射 [英] ARKit – Raycasting using a world ray instead of a screen point

问题描述

我想实现类似ARCore 的光线投射方法，它采用世界空间坐标中的任意光线而不是屏幕空间点:

I want to achieve something similar like ARCore's raycast method which takes an arbitrary ray in world space coordinates instead of a screen-space point:

List<HitResult> hitTest (float[] origin3, int originOffset, float[] direction3, int directionOffset)

我看到 ARKit 本身没有那样的方法，但无论如何也许有人有想法！

I see ARKit itself has not that method like that, but in any way maybe someone has an idea!

谢谢.

推荐答案

在 Apple RealityKit 2.0 和 ARKit 4.0 框架中，您可以找到三种主要的 Raycast 方法: ARView Raycast、ARSession Raycast 和 Scene Raycast(或 World Raycast).所有用 Swift 编写的方法:

In Apple RealityKit 2.0 and ARKit 4.0 frameworks you can find three main types of Raycast methods: ARView Raycast, ARSession Raycast and Scene Raycast (or World Raycast). All methods written in Swift:

此实例方法执行光线投射，其中光线从相机中心通过视图中的一个点投射到场景中，并立即返回结果.您可以在 ARKit 中使用这种类型的光线投射.

This instance method performs a ray cast, where a ray is cast into the scene from the center of the camera through a point in the view, and the results are immediately returned. You can use this type of raycast in ARKit.

func raycast(from point: CGPoint, 
        allowing target: ARRaycastQuery.Target, 
              alignment: ARRaycastQuery.TargetAlignment) -> [ARRaycastResult]

此实例方法针对给定原点、方向和长度的光线对场景中的所有几何体执行凸光线投射.

This instance method performs a convex ray cast against all the geometry in the scene for a ray of a given origin, direction, and length.

func raycast(origin: SIMD3<Float>, 
          direction: SIMD3<Float>,
              query: CollisionCastQueryType, 
               mask: CollisionGroup, 
         relativeTo: Entity) -> [CollisionCastHit]

此实例方法随着时间的推移重复光线投射查询，以通知您物理环境中的更新表面.您可以在 ARKit 3.5 中使用这种类型的光线投射.

This instance method repeats a ray-cast query over time to notify you of updated surfaces in the physical environment. You can use this type of raycast in ARKit 3.5.

func trackedRaycast(_ query: ARRaycastQuery, 
              updateHandler: @escaping ([ARRaycastResult]) -> Void) -> ARTrackedRaycast?

这个 RealityKit 的实例方法也执行跟踪光线投射，但这里光线从相机中心通过视图中的一个点投射到场景中.

This RealityKit's instance method also performs a tracked ray cast, but here a ray is cast into the scene from the center of the camera through a point in the view.

func trackedRaycast(from point: CGPoint, 
               allowing target: ARRaycastQuery.Target, 
                     alignment: ARRaycastQuery.TargetAlignment, 
                 updateHandler: @escaping ([ARRaycastResult]) -> Void) -> ARTrackedRaycast?

import RealityKit

let startPosition: SIMD3<Float> = [3,-2,0]
let endPosition: SIMD3<Float> = [10,7,-5]
let query: CollisionCastQueryType = .all
let mask: CollisionGroup = .all

let raycasts: [CollisionCastHit] = arView.scene.raycast(from: startPosition, 
                                                          to: endPosition, 
                                                       query: query,  
                                                        mask: mask, 
                                                  relativeTo: nil)

guard let rayCast: CollisionCastHit = raycasts.first
else { 
    return 
}

代码片段 02:

import ARKit

let query = arView.raycastQuery(from: screenCenter,
                            allowing: .estimatedPlane,
                           alignment: .any)

let raycast = session.trackedRaycast(query) { results in

    if let result = results.first {
        object.transform = result.transform
    } 
}

raycast.stop()

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