Excluding groups

[AntonyDream]

Is it possible to exclude one group of shapes from collision with cpSpaceSegmentQueryFirst without using different layers?

I'm trying to implement laser ray shooting and don't want to hit shooter's shape while it still can collide with other shapes.

[slembcke]

Yes. It's actually the same answer to a slightly different question from this morning here:
viewtopic.php?f=1&t=3076#p12907

You use the "group" property of a shape actually. Your question was so close to answering itself.

[AntonyDream]

Omg, I just thought this property works in opposite way
Thanks for make it clear for me!

By the way, if I ever want to hit only one group except others, what should I use in this case?

[drey08]

[AntonyDream]

[slembcke]

That's a common misconception actually. :-\ While it's intuitive that the layers work the same for queries and collisions, people often think that groups work the opposite way.

@AnthonyDream If you want it to work the other way around, you can always implement the callback based iterator and filter them yourself. The "nearest" and "first" versions of the query functions don't really do anything particularly special**. Zamaster has a good description here: viewtopic.php?f=1&t=3076&p=12916#p12906

** Not exactly true. It's built on the spatial indexing function which work similarly, but make it possible to exit a query early. https://github.com/slembcke/Chipmunk2D/ ... ery.c#L111