NSUndoManager and GLKit

Question

I'm trying to support undo/redo in an iOS app that uses GLKit.

When I try the following:

GLKVector3 currentTranslation = _panningObject.translation;
[[self.undoManager prepareWithInvocationTarget:_panningObject] setTranslation:currentTranslation];

I get a crash:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[NSMethodSignature signatureWithObjCTypes:]: unsupported type encoding spec '(' in '4(_GLKVector3={?=fff}{?=fff}{?=fff}[3f])8''

Any ideas?

Went ahead and made a bug report: Bug ID# 14794394. Sample project is available here: http://files.thermoglobalnuclearwar.com/GLKitBugs.zip — Tom Irving, Aug 21 '13 at 11:04
What's `_panningObject`? You might want to provide just *a wee bit* more information.. — cacau, Mar 18 '14 at 08:50
It's an object with a translation property of type GLKVector3 — Tom Irving, Mar 18 '14 at 17:04
Ok - I suppose changing the `setTranslation:` method to use an Obj-C wrapper would work. It does appear to expect the `GLKVector3` struct to be a proper Obj-C object. — cacau, Mar 21 '14 at 11:44
See the links to the Tweets in my answer. Explains the problem. — Tom Irving, Mar 21 '14 at 12:56
The core of this issue is that `NSMethodSignature`'s `+signatureWithObjCTypes:` method doesn't support union types. More info at http://lists.apple.com/archives/cocoa-dev/2013/Sep/msg00107.html — Slipp D. Thompson, Oct 05 '15 at 23:07

Tom Irving · Answer 1 · 2013-08-21T11:30:56.327

Still got no idea why GLKVector3 won't play nice, but I'm using this as a workaround:

- (void)setObject:(DrawableObject *)object translationX:(CGFloat)x y:(CGFloat)y z:(CGFloat)z {

    GLKVector3 translation = GLKVector3Make(x, y, z);
    GLKVector3 currentTranslation = object.translation;
    [[self.undoManager prepareWithInvocationTarget:self] setObject:object
                                                      translationX:currentTranslation.x y:currentTranslation.y z:currentTranslation.z];

    [object setTranslation:translation];
}

EDIT:

https://twitter.com/bddckr/status/370144778090192896 https://twitter.com/bddckr/status/370145021804425216

NSUndoManager and GLKit

1 Answers1