Chipmunk 6.0 Beta

[JavierTapulous]

Man it's looking great!, no more crashes and i've been putting it to the test hardcore.

UPDATE: the problem i had was my own. No problems found so far

[slembcke]

@viblio: Oooooh. cpArbiterTotalImpulse()... I misread that as the arbiter normal.

Actually... That turns out it's a bug in both versions. The cpArbiterTotalImpulse() functions don't flip the normal if the collision order is swapped, but they should. You were probably just lucky that it never happened before. I added it to the list of bugs to fix (in both 5 and 6).

[ddeaco]

Glad to hear, the new version is coming along nicely. Over on the cocos2D forums you mentioned a few other ideas you had...

Other current ideas we want to try and work in include support for breakable shapes, bring back proper support for breakable joints, buoyancy, new constraint types (including some for creating top-down vehicles)

And

auto geometry" code for Objective-Chipmunk

I am soon going to be starting work on a new prototype and was interested in the current state of these feature in perticular?

Thanks
David.

[slembcke]

I tried out some ideas for an API for breakable shapes, but it was really tedious as a C API. The breakable joints are still doable, but I felt at some point I had to stop holding back on the release for "just one more feature". So that will probably come soon in a point release. Same with the top down joints.

The auto-geometry stuff works already, it just doesn't have a nice API to wrap it yet. I have some sample code that works with CGImageRefs though. Another example of a feature that I really need to ship instead of sitting on it forever. It's been mostly unchanged for like 6 months now. :-\

[ddeaco]

Thanks for the update, i was really hoping for the topdown joints..

I know its very hard to put an time scale on these things but any ideas when they might happen?

[slembcke]

Well, my first priority at this point is to get Chipmunk 6 documented and shipping. The beta has gone pretty well so far, nobody has really found any major bugs. Then I can start on some enhancements again. I'll be fairly busy for the next 6 weeks or so finishing a contract that our company took on, but I'll have some time this weekend (and probably others). As for when I expect to start having new features going in again? Maybe 2 months? I'd love to work on Chipmunk full time, but it just doesn't make us that much money. :-/

You can still implement breakable joints now fairly easily too. After calling cpSpaceStep(), you can do something like this for each joint you want to break:

Code: Select all

if(cpvlength(cpContraintGetImpulse(joint)) > breakThreshold){
  cpSpaceRemoveConstraint(space, joint);
}

What I was going to do was to add pre and post-step callbacks to constraints so that you could make the process slightly more reusable, but you would still have to do fundamentally the same thing.

[ddeaco]

Thanks for the hint!

One thing that might make some money, a feature GUI full editor that spits out code you can drop into your game... I have seen a few vertex editors but nothing that allows an easy way to setup complex machines.
Thanks David

[viblo]

A small thing I noticed when testing the sleep functions is that a body must be attached to a space before it can sleep, but Im guessing that is by design?

[slembcke]

Rogue bodies don't sleep because they are assumed to be user controlled when they are not added to the space. They even prevent anything jointed to or touching them from sleeping as well. (this is in the docs for rogue bodies)

[viblo]

Ok, as I thought then..
Another thing, cpBodyIsStatic is not included in chipmunk_ffi.h? Shouldn't it be there?

edit: Found another: the asserts in cpBodySleepWithGroup that check if the bodies are sleeping when passed into the method seems wrong? Either the comment or a missing !.