Spatial newton body search

[JernejL]

Newton must have a internal structure, which is efficient for AABB body searches in order to perform collision checks as fast as it does.

I wonder, could that functionality be exposed to users? i'm having a real problem lately finding bodies in proximity of points (very slow performance issue), what i need is something like..

int NewtonBodiesInAABB(startpoint, endpoint, prefiltercallback, storehere, maxstorelength)

And it would return number of bodies actually found in that AABB (minus prefilter - prefiltering would work similar to how the raycast callback's works).

Could you please add something like this to newton?

[Julio Jerez]

but it isnt' that what Bodie is AABB does, can you elaborate better?

[JernejL]

I just need a list of bodies that their central points or AABBs intresect a particular AABB, so i can later perform more precise distance checks on them - in order to know which bodies are in range of explosions, fires and radius triggers in my game.

Currently i have to compare every body at every particle, which slows down terribly when i reach a lot of particles (> 3000), this is the slowest part of my game, and i would spend another week implementing R-tree or something similar unless i could use newton's spatial body management from newton to get this information, which it probably has internally.

[Julio Jerez]

can you give me and example? I am still confuse GetBodyInAABB returns the bodies that intesert the AABB.
but that is what you are describing you wna the funtion to do.

[JernejL]

Oh wow, i didn't know there was already a NewtonWorldForEachBodyInAABBDo

Kinda explains why i shouldn't be coding at 5 AM anymore

[JernejL]

A question for julio - before i try and figure it out by brute force:

Does NewtonWorldForEachBodyInAABBDo use body AABB check Vs provided AABB, or does it use the provided AABB and checks against a body centre point?

[Julio Jerez]

it checks the aabb you provide, against the AABB of the bodies

[JernejL]

Ok cool, i wrote the wiki page for it: NewtonWorldForEachBodyInAABBDo so it is documented better.

[JernejL]

The NewtonWorldForEachBodyInAABBDo is amazing, i started using it everywhere.

I use it now to integrate my particle system with the engine better (searching for neighbouring objects on which particles have effects such as explosions, fire, etc..), it's much faster than what i wrote previously (simple distance comparison loops for each entity vs each particle).

What algorythm does this function use internally that it is so fast? i'm guessing a kind of R-tree? well whatever it uses.. it is really fast!

[Julio Jerez]

Newton uses a mutl resulution grid for broad phase collision.

remember is version 2.14 the prototype nwo takes the user data callback.

[JernejL]

Newton uses a mutl resulution grid for broad phase collision.

remember is version 2.14 the prototype nwo takes the user data callback.

Yep i'm already using 2.14 with the new userdata param in callback, and it works great