Extend examples

[diarmidmackenzie]

This PR covers:

• breaking out examples into 3 sets, covering Cannon local, Cannon worker & Ammo
• creating equivalent Ammo examples for each Cannon example
• as part of this, implementing Ammo equivalents of the utility compenents used in examples: force-pushable, grab, rain-of-entities.
• enhancement to Ammo driver to support configuration of restitution on bodies.
• enhancement to Ammo driver to support spring constraints
• fixing VR grabbing for both Cannon and Ammo examples
• major rework of docs: break Cannon-specific info into separate CannonDriver.md and make top-level doc even-handed regarding Ammo & Cannon
• document warnings about Cannon Worker having lots of bugs at the moment
• include mention of new C-Frame physx repo, and presentation of physx as an alternative to aframe-physics-system, including some pros & cons

Work on this PR has also uncovered a few issues that it has not resolved - these have been raised separately for future investigation. See issues #7, #8, #9, #10

If you want to see a live staged version of all the changes, ahead of this being merged, you can see that here:
https://diarmidmackenzie.github.io/aframe-physics-system/

[kylebakerio]

throwing this link here, instead of just code comments, so that github hooks it in to that conversation for google and such: n5ro#171

[kylebakerio]

review just on initial read through, haven't tried examples yet.

[kylebakerio]

Love the examples, great work.

I get no reticle on the contraints for ammo page, the way I do on constraints for cannon. Are you aware of that and chose not to do it, or is it an error or oversight? Not a reason to deny the pull request, but nice to have if you were intending it.

[kylebakerio]

Would also be nice if the examples were separated under 'cannon' and 'ammo' categories.

I also feel like the 'attached to cone' in the initial examples for both is pretty awkward... just makes a bad first impression and looks broken. Not saying you should rework that (happy to have it if you are willing), but we should probably do that. Not sure what we should take away from that, but seems like just flipping the cone upside down and having cube on the flat side would be cleaner?

Am I alone in thinking this?

[diarmidmackenzie]

Would also be nice if the examples were separated under 'cannon' and 'ammo' categories.

Did you look at this page?

https://diarmidmackenzie.github.io/aframe-physics-system/examples/

I've realized that this page...
https://diarmidmackenzie.github.io/aframe-physics-system/examples/

... has a link to the non-updated examples here:
https://c-frame.github.io/aframe-physics-system/examples/

So maybe that caused some confusion?

[diarmidmackenzie]

I get no reticle on the contraints for ammo page

https://diarmidmackenzie.github.io/aframe-physics-system/examples/ammo/constraints.html

(see prev. comment, maybe you ended up one one of the non-updated pages due to incorrect absolute link)

[diarmidmackenzie]

I also feel like the 'attached to cone' in the initial examples for both is pretty awkward...

Yes, agreed. I'll try to do something to improve this.

[diarmidmackenzie]

I also feel like the 'attached to cone' in the initial examples for both is pretty awkward...

Yes, agreed. I'll try to do something to improve this.

Just moving the cone 1m to the left so the 2 objects are near to each other but don't intersect or z-fight makes this look a lot better IMO. I still don't love the example, but I'd rather work on new, better examples, than invest in this one any further...

[kylebakerio]

I'm sure the incorrect links were the issue.

Going to the ammo example now, I get a reticle, but I get broken examples.

...then, after pasting this image and being here, and flipping back to the tab in question, suddenly the example are now working.

Interesting. My internet is very slow here today, so that is probably the cause, figured I'll post anyways since it's interesting that that's possible.

[kylebakerio]

Is there anything left pending before this is ready for merge?

[kylebakerio]