ARImageAnchor变换矩阵的坐标与ARPlaneAnchor变换矩阵的区别太大-Java 学习之路

我做的很简单：

垂直平面检测
垂直平面上的图像识别

图像挂在检测到的平面上（在我的墙上） . 在这两种情况下，我都从ARSCNViewDelegate实现 renderer:didAddNode:forAnchor: 函数 . 我站在垂直平面检测和图像识别的地方 .

func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    guard let shipScene = SCNScene(named: "ship.scn"), let shipNode = shipScene.rootNode.childNode(withName: "ship", recursively: false) else { return }
    shipNode.position = SCNVector3(anchor.transform.columns.3.x, anchor.transform.columns.3.y, anchor.transform.columns.3.z)
    sceneView.scene.rootNode.addChildNode(shipNode)
    print(anchor.transform)
}

在垂直平面检测的情况下， anchor 将是 ARPlaneAnchor . 在图像识别的情况下， anchor 将是 ARImageAnchor .

为什么这两个锚点的变换矩阵如此不同？我正在打印 anchor.transform ，我得到了这些结果：

1 .

simd_float4x4([
    [0.941312,  0.0,        -0.337538,  0.0)],
    [0.336284,  -0.0861278, 0.937814,   0.0)],
    [-0.0290714,-0.996284,  -0.0810731, 0.0)],
    [0.191099,  0.172432,   -1.14543,   1.0)]
])

2 .

simd_float4x4([
    [0.361231,  0.10894,    0.926093,   0.0)],
    [-0.919883, -0.121052,  0.373049,   0.0)],
    [0.152743,  -0.986651,  0.0564843,  0.0)],
    [75.4418,   10.9618,    -14.3788,   1.0)]
])

因此，如果我想在检测到的垂直平面上放置一个3D对象，我可以简单地使用 [x = 0.191099, y = 0.172432, z = -1.14543] 作为坐标来设置我的节点的位置（ myNode ），然后使用 sceneView.scene.rootNode.addChildNode(myNode) 将此节点添加到场景中，但是如果我想放置一个3D对象在检测到的图像的锚点，我不能使用 [x = 75.4418, y = 10.9618, z = -14.3788] .

如何在检测到的图像锚点上放置3D对象？我真的不明白ARImageAnchor的变换矩阵 .

1 回答

以下是我使用 func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) 方法的示例：

func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {

    //1. If Out Target Image Has Been Detected Than Get The Corresponding Anchor
    guard let currentImageAnchor = anchor as? ARImageAnchor else { return }

    let x = currentImageAnchor.transform
    print(x.columns.3.x, x.columns.3.y , x.columns.3.z)

    //2. Get The Targets Name
    let name = currentImageAnchor.referenceImage.name!

    //3. Get The Targets Width & Height In Meters
    let width = currentImageAnchor.referenceImage.physicalSize.width
    let height = currentImageAnchor.referenceImage.physicalSize.height

    print("""
    Image Name = \(name)
    Image Width = \(width)
    Image Height = \(height)
    """)

    //4. Create A Plane Geometry To Cover The ARImageAnchor
    let planeNode = SCNNode()
    let planeGeometry = SCNPlane(width: width, height: height)
    planeGeometry.firstMaterial?.diffuse.contents = UIColor.white
    planeNode.opacity = 0.25
    planeNode.geometry = planeGeometry

    //5. Rotate The PlaneNode To Horizontal
    planeNode.eulerAngles.x = -.pi/2

    //The Node Is Centered In The Anchor (0,0,0)
    node.addChildNode(planeNode)


    //6. Create AN SCNBox
    let boxNode = SCNNode()
    let boxGeometry = SCNBox(width: 0.1, height: 0.1, length: 0.1, chamferRadius: 0)

    //7. Create A Different Colour For Each Face
    let faceColours = [UIColor.red, UIColor.green, UIColor.blue, UIColor.cyan, UIColor.yellow, UIColor.gray]
    var faceMaterials = [SCNMaterial]()

    //8. Apply It To Each Face
    for face in 0 ..< 5{
        let material = SCNMaterial()
        material.diffuse.contents = faceColours[face]
        faceMaterials.append(material)
    }
    boxGeometry.materials = faceMaterials
    boxNode.geometry = boxGeometry

    //9. Set The Boxes Position To Be Placed On The Plane (node.x + box.height)
    boxNode.position = SCNVector3(0 , 0.05, 0)

    //10. Add The Box To The Node
    node.addChildNode(boxNode)


}

从我的理解（我当然可能是错误的）你会知道你的位置区域是 referenceImage.physicalSize 的宽度和高度，以米为单位表示：

let width = currentImageAnchor.referenceImage.physicalSize.width
let height = currentImageAnchor.referenceImage.physicalSize.height

因此，您需要在这些边界内扩展您的内容（如果需要适合），假设您希望它看起来覆盖图像 .

回复于 2024-04-23T14:10:28+08:00

ARImageAnchor变换矩阵的坐标与ARPlaneAnchor变换矩阵的区别太大

1 回答

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