Question

Simple question. What is the best way to turn a CGPoint into a GLKVector?

These structures are identical so it would be nice to be able to reinterpret_cast or memcpy or something like that. My solution below works but hardly seems optimum. I’m creating a GLKVector2 on the stack assigning each member then returning this as a value which is then assigned to another GLKVector.

It’s not going to break the bank or anything but there must be a neater way to do this?

GLKVector2 Vector2FromPoint(CGPoint point)
{
    GLKVector2 v;
    v.x = point.x;
    v.y = point.y;
    return v;
}

Answer 1

You could try using memcpy in a function like this:

bool vector2ToCGPoint(GLKVector2* s, CGPoint* d) {
    memcpy(d, s, sizeof(*d));
}

but then it is probably better to have:

bool copyVector2ToCGPoint(GLKVector2* s, CGPoint* d) {
     d.x = s.x;
     d.y = s.x;
}

if you really want optimization, you could go for a macro:

#define copyS2D(S,D) (D.x = S.x, D.y = S.y)

so you can do:

CGPoint b;
GLKVector2 a;
vector2FromCGPoint(a, b);

of course, as you know, macros will not be that much type-safe…