Re: [Adonthell-devel] eSpacePosition/Velocity

[Kai Sterker]

On Fri, Apr 2, 2010 at 4:15 AM, Tyler Nielsen <address@hidden> wrote:

> Can you give me a quick rundown on what these are?  I see one comment in the
> code that stays:
[...]
> I looks like it's really changing coordinate space also (so that one unit in
> eSpace = one Radius of the object).

That's exactly what it does :-).

> I'm just not sure how this is useful,
> and how you would compare it to another object with different dimensions.

The trick is to make that object undergo the same transformation,
which happens in collision::check_triangle:

    // translate triangle into espace
    triangle3<float> eTriangle = triangle.translate (Radius, offset);

The offset parameter is actually the object's coordinate on the world
map, which is determined in moving::collide_with_objects:

    // ... and check if collision occurs
    shape->collide (collisionData, (*i)->Min-(*i)->get_object()->entire_min());

(That's one of the places you already changed, it seems).


The whole collision stuff doesn't come out of nowhere, however. It's taken from

    http://www.peroxide.dk/papers/collision/collision.pdf

with some more changes and bugfixes from the accompanying forum

    
http://mrgamemaker.yuku.com/topic/368/t/Telemachos-tutorial-Improved-collision-detection-amp-resp.html


Hope that helps,

Kai