Question

我相信这可能是一个iOS错误，我已经通过Bug Report向Apple报告了这个错误。我会在这里发布，以防我可以使用的一些解决方法，或解释原因。

我想在SceneKit中绘制UIBezierPath的笔划。我使用CGPath copyStrokingWithWidth函数，然后使用给定路径创建SCNShape。

这适用于有2个点的行，但在有3个点的行上，SCNShape不会显示任何内容。我确定只有当lineWidth大于0.1时才会出现这种情况。将lineWidth设置为0.1后，它会完美显示。

let strokeBezierPath = UIBezierPath()
strokeBezierPath.lineWidth = 1
strokeBezierPath.move(to: CGPoint.zero)
strokeBezierPath.addLine(to: CGPoint(x: 10, y: 0))
strokeBezierPath.addLine(to: CGPoint(x: 10, y: 10))
let cgPath = strokeBezierPath.cgPath.copy(
    strokingWithWidth: strokeBezierPath.lineWidth,
    lineCap: strokeBezierPath.lineCapStyle,
    lineJoin: strokeBezierPath.lineJoinStyle,
    miterLimit: strokeBezierPath.miterLimit)

let bezierPath = UIBezierPath(cgPath: cgPath)
let shape = SCNShape(path: bezierPath, extrusionDepth: 1)
shape.firstMaterial?.diffuse.contents = UIColor.blue
let node = SCNNode(geometry: shape)
node.position.z = -40

sceneView.scene.rootNode.addChildNode(node)

这适用于：

只是前2分
线宽0.1
覆盖同一区域的手动绘制贝塞尔曲线路径

将UIBezierPath打印为线宽为0.1（显示）：

<UIBezierPath: 0x1d00b12e0; <MoveTo {0, 0.050000000000000003}>,
 <LineTo {10, 0.050000000000000003}>,
 <LineTo {9.9499999999999993, 10}>,
 <LineTo {10.050000000000001, 10}>,
 <LineTo {10.050000000000001, 0}>,
 <LineTo {0, -0.050000000000000003}>,
 <LineTo {0, 0.050000000000000003}>,
 <Close>

线宽为0.2（不显示）：

<UIBezierPath: 0x1d00b7160; <MoveTo {0, 0.10000000000000001}>,
 <LineTo {10, 0.10000000000000001}>,
 <LineTo {9.9000000000000004, 0}>,
 <LineTo {9.9000000000000004, 10}>,
 <LineTo {10.1, 10}>,
 <LineTo {10.1, 0}>,
 <LineTo {10, -0.10000000000000001}>,
 <LineTo {0, -0.10000000000000001}>,
 <LineTo {0, 0.10000000000000001}>,
 <Close>

Answer 1

   let strokeBezierPath = UIBezierPath()
          strokeBezierPath.lineWidth = 1   
          strokeBezierPath.move(to: CGPoint.zero)
          strokeBezierPath.addLine(to: CGPoint(x: 10, y: 0))
          strokeBezierPath.addLine(to: CGPoint(x: 10, y: 10))

您还没有关闭路径。您将无法挤出两个尚未关闭的线段...因此不会显示任何内容。使用以下命令关闭路径。这将在sceneView中显示您的几何体。

    strokeBezierPath.close()

编辑：Scenekit单位以米为单位。所以要在你面前使用较小的物体。将您的单位和线宽更改为以下内容。这将把物体放在前面1米......而且要小得多，这样你就可以看到更好的了。

let strokeBezierPath = UIBezierPath()
    strokeBezierPath.lineWidth = 0.01
    strokeBezierPath.move(to: CGPoint.zero)
    strokeBezierPath.addLine(to: CGPoint(x: 0.1, y: 0))
    strokeBezierPath.addLine(to: CGPoint(x: 0.1, y: 0.1))
    strokeBezierPath.addLine(to: CGPoint(x: 0.0, y: 0.1))
    strokeBezierPath.addLine(to: CGPoint(x: 0, y: 0))
    strokeBezierPath.close()
    let cgPath = strokeBezierPath.cgPath.copy(
        strokingWithWidth: strokeBezierPath.lineWidth,
        lineCap: strokeBezierPath.lineCapStyle,
        lineJoin: strokeBezierPath.lineJoinStyle,
        miterLimit: strokeBezierPath.miterLimit)

    let bezierPath = UIBezierPath(cgPath: cgPath)
    let shape = SCNShape(path: bezierPath, extrusionDepth: 0.01)
    shape.firstMaterial?.diffuse.contents = UIColor.blue
    let node = SCNNode(geometry: shape)
    node.position.z = -1

    sceneView.scene.rootNode.addChildNode(node)

SCNShape在某些情况下不使用UIBezierPath进行绘制

1 个答案: