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
我修好了它。好像图像被放大了。如果我做imageMaterial.diffuse.contentsTransform = SCNMatrix4MakeScale(32, 32, 0)
,图像会重复。
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
}
}