Long click on a plane => -[SCNNode changeMaterial]: unrecognized selector sent to instance about arkit-by-example HOT 6 OPEN

Here's my workaround.

@interface SCNNode (Damn)
- (void)changeMaterial;
@end

@implementation SCNNode (Damn)
- (void)changeMaterial
{
    NSLog(@"changeMaterial sent to instance of %@",[self class]);
}
@end

from arkit-by-example.

I don't understand your workaround. May you elaborate ? Thanks !

from arkit-by-example.

Some instance of SCNNode is being sent the message changeMaterial that does not implement changeMaterial. Only the subclass Cube implements changeMaterial but the code sending the message isn't checking that the node it is sending changeMaterial is a Cube (or better - respondsToSelector:@selector(changeMaterial)).

So I added a category to SCNNode called changeMaterial that simply logs the message. It is overridden by the method in Cube. So now it is no longer an "error" to send changeMaterial to any SCNNode.

from arkit-by-example.

The problem is that with your solution the user has to click several times on the plane in order to be able to change its material. He has to click until the correct instance (Plane) is returned. This is not satisfying. I don't understand why the plane is not detected reliably when I click on it.

from arkit-by-example.

from arkit-by-example.

If it's not a Cube, check if it's a Plane then call changeMaterial

.......
if ([parentNode isKindOfClass:[Cube class]]) {
[((Cube *)parentNode) changeMaterial];
} else if ([parentNode isKindOfClass:[Plane class]]) {
[((Plane *)parentNode) changeMaterial];
}

I think the hit detection problem is that before hitting a Plane it can hit a feature point

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