OpenGL ES 案例03：CoreAnimation绘制立方体+旋转

在不会OpenGL ES的情况下，如何利用CoreAnimation实现一个立方体，并旋转，整体效果如下

整体实现的思路如下

主要分为两部分

• ViewDidLoad函数：初始化工作
• update更新：定时器实现旋转

ViewDidLoad函数

初始化工作包含两部分：

• addFaces：添加6个面，通过变换组合成立方体
• addCADisplayLink：添加定时器，并放入runloop

addFaces函数
这部分主要是将6个面作相应的变换添加到容器中

• OC版本

//添加面
- (void)addFaces{
    self.faces = @[_view0, _view1, _view2, _view3, _view4, _view5];
    
//    主view
    CATransform3D perspective = CATransform3DIdentity;
//    核心动画设置透视投影
    perspective.m34 = -1.0 / 500.0;
//    围绕x，y分别旋转，M_PI_4 = π/4，π=180°
//      x:顺时针旋转45°，y：顺时针旋转45°
    perspective = CATransform3DRotate(perspective, -M_PI_4, 1, 0, 0);
    perspective = CATransform3DRotate(perspective, -M_PI_4, 0, 1, 0);
    self.containerView.layer.sublayerTransform = perspective;
    
    //添加face1
//    z轴平移100
//    （除了第一个视图外，其余的视图都是基于第一个视图的位置进行平移+旋转的）
    CATransform3D transform = CATransform3DMakeTranslation(0, 0, 100);
    [self addFace:0 withTransform:transform];
    
////    添加face2 --平移y+旋转y
    transform = CATransform3DMakeTranslation(100, 0, 0);
    transform = CATransform3DRotate(transform, M_PI_2, 0, 1, 0);
    [self addFace:1 withTransform:transform];
//
//     添加face3 -- 平移y+旋转x
    transform = CATransform3DMakeTranslation(0, -100, 0);
    transform = CATransform3DRotate(transform, M_PI_2, 1, 0, 0);
//    [self addFace:2 withTransform:transform];
    
//    添加face4 -- 平移y+旋转x
    transform = CATransform3DMakeTranslation(0, 100, 0);
    transform = CATransform3DRotate(transform, -M_PI_2, 1, 0, 0);
    [self addFace:3 withTransform:transform];

//    添加face5 -- 平移+旋转
    transform = CATransform3DMakeTranslation(-100, 0, 0);
    transform = CATransform3DRotate(transform, -M_PI_2, 0, 1, 0);
    [self addFace:4 withTransform:transform];

//    添加face6 -- 平移z+旋转y
    transform = CATransform3DMakeTranslation(0, 0, -100);
    transform = CATransform3DRotate(transform, M_PI, 0, 1, 0);
    [self addFace:5 withTransform:transform];
}

- (void)addFace: (NSInteger)index withTransform: (CATransform3D)transform
{
//    获取face视图，并将其加入容器中
    UIView *face = self.faces[index];
    [self.containerView addSubview:face];
    
//    将face视图放在容器的中心
    CGSize containerSize = self.containerView.bounds.size;
    face.center = CGPointMake(containerSize.width/2.0, containerSize.height/2.0);
    
//    添加tansform，tansform就是一个矩阵
    face.layer.transform = transform;
}

• Swift版本

fileprivate func addFaces(){
        faces = [view0, view1, view2, view3, view4, view5]
        
//        父view的layer图层
        var perspective: CATransform3D = CATransform3DIdentity
        perspective.m34 = -1.0 / 500.0
        perspective = CATransform3DRotate(perspective, -.pi/4, 1, 0, 0)
        perspective = CATransform3DRotate(perspective, -.pi/4, 0, 1, 0)
        self.containerView.layer.sublayerTransform = perspective
        
//        添加face1
        var transform = CATransform3DMakeTranslation(0, 0, 100)
        self.addFaceWithTransform(0, transform)
        
//        添加face2
        transform = CATransform3DMakeTranslation(100, 0, 0)
        transform = CATransform3DRotate(transform, .pi/2, 0, 1, 0)
        self.addFaceWithTransform(1, transform)
        
//        添加face3
        transform = CATransform3DMakeTranslation(0, -100, 0)
//        transform = CATransform3DRotate(transform, .pi/2, 1, 0, 0)
//        self.addFaceWithTransform(2, transform)
//
//        添加face4
        transform = CATransform3DMakeTranslation(0, 100, 0)
        transform = CATransform3DRotate(transform, -.pi/2, 1, 0, 0)
        self.addFaceWithTransform(3, transform)
//
//        添加face5
        transform = CATransform3DMakeTranslation(-100, 0, 0)
//        transform = CATransform3DRotate(transform, -.pi/2, 0, 1, 0)
        self.addFaceWithTransform(4, transform)
//
////        添加face6
//        transform = CATransform3DMakeTranslation(0, 0, -100)
//        transform = CATransform3DRotate(transform, .pi, 0, 1, 0)
//        self.addFaceWithTransform(5, transform)

    }
    
    private func addFaceWithTransform(_ index: Int, _ transform: CATransform3D){
//        获取face，并加入容器中
        let face = self.faces[index]
        self.containerView.addSubview(face)
        
//        将face视图放入容器的中心
        let containerSize = self.containerView.bounds.size
        face.center = CGPoint(x: containerSize.width/2, y: containerSize.height/2)
        
//        添加transform
        face.layer.transform = transform
        
    }

addCADisplayLink函数
这部分主要初始化定时器，并将定时器加入runloop循环中

• OC版本

//添加定时器
- (void)addCADisplayLink{
    self.angle = 0;
    self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(update)];
    [self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}

• Swift版本

fileprivate func addCADisplayLink(){
    self.displayLink.add(to: RunLoop.main, forMode: .common)
   }

update更新

主要是计算旋转度数，并将容器的子layer围绕任意方向旋转

• OC版本

- (void)update{
    
//    计算旋转度数
    self.angle = (self.angle + 5) % 360;
//    将度数转化为弧度
    float deg = self.angle * (M_PI / 180);
    CATransform3D temp = CATransform3DIdentity;
//    围绕（0.3, 1, 0.7）方向旋转
    temp = CATransform3DRotate(temp, deg, 0.3, 1, 0.7);
//    旋转容器的子layer
    self.containerView.layer.sublayerTransform = temp;
}

• Swift版本

@objc fileprivate func update(){
    self.angle = (self.angle+5).truncatingRemainder(dividingBy: 360)
    let deg = self.angle * (.pi/180)
    var temp = CATransform3DIdentity
    temp = CATransform3DRotate(temp, CGFloat(deg), 0.3, 1, 0.7)
    
    self.containerView.layer.sublayerTransform = temp
   }

完整的代码见github - 09_CoreAnimation_立方体+旋转_OC、09_CoreAnimation_立方体+旋转_Swift，分别提供了OC和Swift版本