Question

我有一个SCNSphere，我希望以屏幕像素（或更准确地说，点数）获得其投影尺寸。

我认为这样做会：

Inno Setup Compiler

然而，这不起作用。 let bounds = endNode.boundingBox let projectedMin = renderer.projectPoint(bounds.min) let projectedMax = renderer.projectPoint(bounds.max) let sizeInPts = CGSize(width: CGFloat(projectedMax.x - projectedMin.x), height: CGFloat(projectedMax.y - projectedMin.y))中的宽度和高度总是偏离。

Answer 1

我认为你应该检查边界框的所有顶点我没有测试这段代码，但我希望它有效。

let (localMin, localMax) = endNode.boundingBox
let min = endNode.convertPosition(localMin, to: nil)
let max = endNode.convertPosition(localMax, to: nil)
let arr = [
    renderer.projectPoint(SCNVector3(min.x, min.y, min.z)),
    renderer.projectPoint(SCNVector3(max.x, min.y, min.z)),
    renderer.projectPoint(SCNVector3(min.x, max.y, min.z)),
    renderer.projectPoint(SCNVector3(max.x, max.y, min.z)),
    renderer.projectPoint(SCNVector3(min.x, min.y, max.z)),
    renderer.projectPoint(SCNVector3(max.x, min.y, max.z)),
    renderer.projectPoint(SCNVector3(min.x, max.y, max.z)),
    renderer.projectPoint(SCNVector3(max.x, max.y, max.z))
]
let minX: CGFloat = arr.reduce(CGFloat.infinity, { $0 > $1.x ? $1.x : $0 })
let minY: CGFloat = arr.reduce(CGFloat.infinity, { $0 > $1.y ? $1.y : $0 })
let minZ: CGFloat = arr.reduce(CGFloat.infinity, { $0 > $1.z ? $1.z : $0 })
let maxX: CGFloat = arr.reduce(-CGFloat.infinity, { $0 < $1.x ? $1.x : $0 })
let maxY: CGFloat = arr.reduce(-CGFloat.infinity, { $0 < $1.y ? $1.y : $0 })
let maxZ: CGFloat = arr.reduce(-CGFloat.infinity, { $0 < $1.z ? $1.z : $0 })

let width = maxX - minX
let height = maxY - minY
let depth = maxZ - minZ

let sizeInPts = CGSize(width: width, height: height)

我将Xcode Playground示例上传到Github。

如何计算SCNNode的大小（以像素为单位）？

1 个答案: