Re: [pygame] The Giant - 'cool project I'm working on now' - thread.

[Michael George <mdgeorge@xxxxxxxxxxxxxx>]

The scheme I've been working on is to compute what I call a "shadow", 
which is the set of all points that would cause a collision if you 
placed the object there.  This is a minkowski sum if you're familiar 
with that term.  Then as the mouse moves, I compute the closest point 
that doesn't fall in the shadow.  So my scheme would handle this case by 
finding the closest place where the object fits.  If you press tab in 
the demo I sent out earlier it shows the shadow.

--Mike

DR0ID wrote:
> Hi
>
> Right, a special case I didnt think off (how often does it apply?). 
> Anyway, it is the collision response that has to handle this. How 
> would you handle this case? Slide it along one of the colliding 
> objects until it 'fits'?
>
> ~DR0ID
>
>
>
> Michael George schrieb:
> > I don't think that works.  Consider an object smooshed between two 
> > others.  The collision from the one on the left would have a vector 
> > pointing to the right.  The collision from the one on the right would 
> > have a vector pointing left, and the sum would be zero (unless I'm 
> > misunderstanding).
> >
> > --Mike
> >
> > DR0ID wrote:
> > > Hi
> > >
> > > Well, you can apply the 'axis separating theorem' to a 'multi 
> > > collision (just test all potential colliding objects). As a result 
> > > you get the penetration depth as a vector, which you could sum up to 
> > > get a general direction to move you object (in Murmel I did this, 
> > > IIRC). But probably you know that already.
> > >
> > > ~DR0ID
> > >
> > > Michael George schrieb:
> > > > Thanks for the pointer.  That looks like good stuff and I haven't 
> > > > come across it before.  I don't think it will apply to my game 
> > > > because of the common case where there's a cluster of objects that 
> > > > you need to respond to, but I will definitely read it through in 
> > > > more detail.
> > > >
> > > > --Mike
> > > >
> > > > DR0ID wrote:
> > > > > Hi
> > > > >
> > > > > here is a good tutorial about 2d collision (probably you already 
> > > > > know): http://www.harveycartel.org/metanet/tutorials.html