Sticking antibodies on a cell

[Julio Jerez]

I was going to say that why not using a compound.

[Pyritie]

Because I wasn't aware of them

I'll see if they're what I need.

[JernejL]

they are THE totally rigid joints that you may want, also constructing them at runtime is usually very fast.

[Pyritie]

Alright, so exams are over so now I can get back to work on this.

I made the compound collision but I got a few problems/questions:

- How do I add an "offset" to parts of the compound collision? My antibodies are small spheres and the cells are big spheres, and when I make a compound collision the small sphere just goes inside the big one. I want the small sphere to stick to the edge of the larger one.
- Both the cell and the antibody have the same collision but they don't "follow" each other as if they were connected. How do I do this?

I'll poke around a bit more and report back if I solve any of my own questions :U

[Pyritie]

bump

[Julio Jerez]

every part on a compound have a offset matrix.

[Pyritie]

where?

[Julio Jerez]

in the shape when you make a sphere the funtion allow fo a matrix offset.

[Pyritie]

so I have to make a sphere collision object with the offset just before creating the compound collision?

What about making the mesh follow around? Or is that just an ogre job?

[Julio Jerez]

To build a compoundg collision first you have to have the parts that will make the compound collision.
The part is and array of convex shapes, each convex shape can face a offset matrix that will translate and rotate the part relative to the center of the compound.
the shape will move with teh body thit is attached to.

[Pyritie]

okay but when I make the antibody, it has to have a regular sphere. Then when it attaches it gets the offset. So I have to make another collision when it attaches. But the only way I can see to set the antibody's Body's collision to the offset one is by creating a new body... am I doing this wrong?

[Julio Jerez]

No, you can just make a new compound and call NewtonSetShape, the othe will be release and destroy.
basically the algorithm is like this

-call GetCollision from the body
-Call GetCollisionInfo of the shape.
-place all the compounds of the old collision into one array
-add the new sphere to the end of the array
-make a compound with thsi new array
-Set this collision to the body.

[Pyritie]

I don't see any GetCollisionInfo. There's GetCollisionPrimitiveType but I get "'MogreNewt.Collision.CollisionPrimitiveType' is inaccessible due to its protection level" when I try to use it.

[Julio Jerez]

void NewtonCollisionGetInfo (const NewtonCollision* collision, NewtonCollisionInfoRecord* collisionInfo);

[Pyritie]

Hm, still not there. I'll ask someone on the OgreNewt forums where they moved it to.