IOS构造透视CATransform3D矩阵

CATransform3D CATransform3DMakePerspective(CGPoint center, float disZ){    CATransform3D transToCenter = CATransform3DMakeTranslation(-center.x, -center.y, 0);    CATransform3D transBack = CATransform3DMakeTranslation(center.x, center.y, 0);    CATransform3D scale = CATransform3DIdentity;    scale.m34 = -1.0f/disZ;        return CATransform3DConcat(CATransform3DConcat(transToCenter, scale), transBack);}CATransform3D CATransform3DPerspect(CATransform3D t, CGPoint center, float disZ){    return CATransform3DConcat(t, CATransform3DMakePerspective(center, disZ));}