在SceneKit中重复平面上的纹理

Question

我有一个32x32 .png图像,我想通过SCNPlane重复.我得到的代码(见下文)导致图像被拉伸以适应平面的大小,而不是重复.

码:

let planeGeo = SCNPlane(width: 15, height: 15)

let imageMaterial = SCNMaterial()
imageMaterial.diffuse.contents = UIImage(named: "art.scnassets/grid.png")

planeGeo.firstMaterial = imageMaterial

let plane = SCNNode(geometry: planeGeo)

plane.geometry?.firstMaterial?.diffuse.wrapS = SCNWrapMode.repeat
plane.geometry?.firstMaterial?.diffuse.wrapT = SCNWrapMode.repeat

Answer 1

我修好了它.似乎图像被放大了.如果我这样做imageMaterial.diffuse.contentsTransform = SCNMatrix4MakeScale(32, 32, 0),图像会重复.

Answer 2

在ARKit中实现平面可视化时,我遇到了同样的问题.我想将检测到的平面可视化为棋盘图案.我通过创建一个名为"PlaneNode" 的自定义SCNNode来修复它,并使用正确配置的SCNMaterial.材质使用wrapS,wrapT = .repeat并根据平面本身的大小正确计算比例.

看起来像这样:

看看下面的代码,内联注释包含解释.

class PlaneNode : SCNNode {

    init(planeAnchor: ARPlaneAnchor) {
        super.init()
        // Create the 3D plane geometry with the dimensions reported
        // by ARKit in the ARPlaneAnchor instance
        let planeGeometry = SCNPlane(width:CGFloat(planeAnchor.extent.x), height:CGFloat(planeAnchor.extent.z))
        // Instead of just visualizing the grid as a gray plane, we will render
        // it in some Tron style colours.
        let material = SCNMaterial()
        material.diffuse.contents = PaintCode.imageOfViewARPlane
        //the scale gives the number of times the image is repeated
        //ARKit givest the width and height in meters, in this case we want to repeat
        //the pattern each 2cm = 0.02m so we divide the width/height to find the number of patterns
        //we then round this so that we always have a clean repeat and not a truncated one
        let scaleX = (Float(planeGeometry.width)  / 0.02).rounded()
        let scaleY = (Float(planeGeometry.height) / 0.02).rounded()
        //we then apply the scaling
        material.diffuse.contentsTransform = SCNMatrix4MakeScale(scaleX, scaleY, 0)
        //set repeat mode in both direction otherwise the patern is stretched!
        material.diffuse.wrapS = .repeat
        material.diffuse.wrapT = .repeat
        //apply material
        planeGeometry.materials = [material];
        //make a node for it
        self.geometry = planeGeometry
        // Move the plane to the position reported by ARKit
        position.x = planeAnchor.center.x
        position.y = 0
        position.z = planeAnchor.center.z
        // Planes in SceneKit are vertical by default so we need to rotate
        // 90 degrees to match planes in ARKit
        transform =  SCNMatrix4MakeRotation(-Float.pi / 2.0, 1.0, 0.0, 0.0);
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func update(planeAnchor: ARPlaneAnchor) {
        guard let planeGeometry = geometry as? SCNPlane else {
            fatalError("update(planeAnchor: ARPlaneAnchor) called on node that has no SCNPlane geometry")
        }
        //update the size
        planeGeometry.width = CGFloat(planeAnchor.extent.x)
        planeGeometry.height = CGFloat(planeAnchor.extent.z)
        //and material properties
        let scaleX = (Float(planeGeometry.width)  / 0.02).rounded()
        let scaleY = (Float(planeGeometry.height) / 0.02).rounded()
        planeGeometry.firstMaterial?.diffuse.contentsTransform = SCNMatrix4MakeScale(scaleX, scaleY, 0)
        // Move the plane to the position reported by ARKit
        position.x = planeAnchor.center.x
        position.y = 0
        position.z = planeAnchor.center.z

    }
}