1.关于layer层的旋转方向问题
layer层遵守 左手坐标系:x向右,y向下,z朝向自己(左手大拇指顺着z轴指去,握紧拳头其余4指由x轴到y轴)
前提:当旋转角度为正数的时候逆时针旋转,当旋转角度为负数的时候顺时针旋转
永远记着xyz的矢量方向性,如绕z轴旋转就是zxy,x-》y为正,为逆时针方向旋转,反之y-》x就是顺时针
如绕x轴旋转就是xyz,y-》z为正数,为逆时针
如绕y轴旋转就是yzx,z-》x就是正数,为逆时针
注意:(xyz无论怎么交换方向性不变永远x-》y-》z)
当绕z轴旋转,x---》y为逆时针
CATransform3D unit =CATransform3DIdentity;//单位矩阵
unit = CATransform3DRotate(unit,M_PI_4, 0,0, 1);//绕Z轴逆时针旋转
https://img-blog.youkuaiyun.com/20160818002718082?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
unit = CATransform3DRotate(unit,M_PI_4, 1,0, 0);//绕x轴逆时针
unit = CATransform3DRotate(unit,M_PI_4, 0,1, 0);
https://img-blog.youkuaiyun.com/20160818002938286?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
unit = CATransform3DRotate(unit, -M_PI_4,0, 1,0);
https://img-blog.youkuaiyun.com/20160818002956214?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center