iOS中的3D变换（二）

级别： ★★☆☆☆
标签：「iOS」「Swift」「CATransform3D」「3D变换」
作者： 大成小栈
审校： QiShare团队

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1. 常用的3D变换方法

CATransform3DScale返回通过缩放现有变换构造的变换矩阵，sx/sy/sz即为x方向、y方向和z方向的缩放比例

CATransform3D CATransform3DScale (CATransform3D t, CGFloat sx,
    CGFloat sy, CGFloat sz)

CATransform3DRotate返回通过旋转现有变换构造的变换矩阵，angle代表弧度，x,y,z代表各个轴上旋转的弧度倍数

CATransform3D CATransform3DRotate (CATransform3D t, CGFloat angle,
    CGFloat x, CGFloat y, CGFloat z)

CATransform3DInvert返回反转后的变换矩阵

CATransform3D CATransform3DInvert (CATransform3D t)

CATransform3DTranslate返回实现x/y/z轴上平移相应距离的变换矩阵

CATransform3D CATransform3DTranslate (CATransform3D t, CGFloat tx,
    CGFloat ty, CGFloat tz)

CATransform3DConcat返回同时作用两种变换矩阵的矩阵

CATransform3D CATransform3DConcat (CATransform3D a, CATransform3D b)

几个特殊的变换矩阵
CATransform3DMakeScale/CATransform3DMakeRotation/CATransform3DMakeTranslation同样是作用于原始视图的变换矩阵

/* Returns a transform that translates by '(tx, ty, tz)':
 * t' =  [1 0 0 0; 0 1 0 0; 0 0 1 0; tx ty tz 1]. */

CATransform3D CATransform3DMakeTranslation (CGFloat tx,
    CGFloat ty, CGFloat tz)

/* Returns a transform that scales by `(sx, sy, sz)':
 * t' = [sx 0 0 0; 0 sy 0 0; 0 0 sz 0; 0 0 0 1]. */

CATransform3D CATransform3DMakeScale (CGFloat sx, CGFloat sy,
    CGFloat sz)

/* Returns a transform that rotates by 'angle' radians about the vector
 * '(x, y, z)'. If the vector has length zero the identity transform is
 * returned. */

CATransform3D CATransform3DMakeRotation (CGFloat angle, CGFloat x,
    CGFloat y, CGFloat z)
CATransform3DIdentity[1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1]，人畜无害矩阵，通常用于恢复初始状态

2. 实现一个旋转的三维立方体

import UIKit

class CATransform3DController: UIViewController {

    var animateCube = UIView.init()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.title = "Transform3D"
        self.view.backgroundColor = .white
        self.edgesForExtendedLayout = [UIRectEdge.left, UIRectEdge.right]

        self.testTransform3D()
    }
    
    func testTransform3D() {
        
        let targetRect = CGRect.init(x: 0, y: 0, width: 200, height: 200)
        animateCube.frame = targetRect
        animateCube.center = self.view.center
        self.view.addSubview(animateCube)
        
        let frontView = UIView.init(frame: targetRect)
        frontView.backgroundColor = UIColor.blue.withAlphaComponent(0.25)
        frontView.layer.transform = CATransform3DTranslate(frontView.layer.transform, 0, 0, 100)
        self.animateCube.addSubview(frontView)
        
        let backView = UIView.init(frame: targetRect)
        backView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
        backView.layer.transform = CATransform3DTranslate(backView.layer.transform, 0, 0, -100)
        self.animateCube.addSubview(backView)
        
        let leftView = UIView.init(frame: targetRect)
        leftView.backgroundColor = UIColor.yellow.withAlphaComponent(0.5)
        leftView.layer.transform = CATransform3DTranslate(leftView.layer.transform, -100, 0, 0)
        leftView.layer.transform = CATransform3DRotate(leftView.layer.transform, CGFloat(Double.pi / 2.0), 0, 1, 0)
        self.animateCube.addSubview(leftView)
        
        let rightView = UIView.init(frame: targetRect)
        rightView.backgroundColor = UIColor.purple.withAlphaComponent(0.5)
        rightView.layer.transform = CATransform3DTranslate(rightView.layer.transform, 100, 0, 0)
        rightView.layer.transform = CATransform3DRotate(rightView.layer.transform, CGFloat(Double.pi / 2.0), 0, 1, 0)
        self.animateCube.addSubview(rightView)
        
        let headView = UIView.init(frame: targetRect)
        headView.backgroundColor = UIColor.orange.withAlphaComponent(0.5)
        headView.layer.transform = CATransform3DTranslate(headView.layer.transform, 0, 100, 0)
        headView.layer.transform = CATransform3DRotate(headView.layer.transform, CGFloat(Double.pi / 2.0), 1, 0, 0)
        self.animateCube.addSubview(headView)
        
        let footView = UIView.init(frame: targetRect)
        footView.backgroundColor = UIColor.green.withAlphaComponent(0.5)
        footView.layer.transform = CATransform3DTranslate(footView.layer.transform, 0, -100, 0)
        footView.layer.transform = CATransform3DRotate(footView.layer.transform, CGFloat(Double.pi / 2.0), -1, 0, 0)
        self.animateCube.addSubview(footView)
        
        self.animateCube.layer.borderColor = UIColor.red.cgColor
        self.animateCube.layer.borderWidth = 2.0
        
        //self.animateCube.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)
        
        //var transform3D: CATransform3D = CATransform3DIdentity
        //transform3D.m34 = -1.0 / 500.0
        //self.animateCube.layer.sublayerTransform = transform3D

        weak var weakSelf = self
        let angle = CGFloat(Double.pi) / -360.0
        var transform3D: CATransform3D = CATransform3DIdentity
        let timer = Timer.init(timeInterval: 1.0 / 60.0, repeats: true) { (_) in
            transform3D = CATransform3DRotate(transform3D, angle, 1, 1, 0.5)
            weakSelf!.animateCube.layer.sublayerTransform = transform3D
        }
        RunLoop.current.add(timer, forMode: RunLoop.Mode.common)
    }
}

示例：

旋转的三维立方体

参考文章：https://www.jianshu.com/p/3dd14cfbdc53
感谢！

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