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Quote: Original post by zedzThis implies that you apply a force to every single one of your 500 objects, every physics timestep?
All my objects will be awake thus have to be tested.
Quote: ATM cpu time consumed byMine goes more like this: Particles, Graphics, Physics, and lastly AI.
-AI largest slice
-physics
-particles
-render setup
Quote: Original post by zedzQuote: but the main disadvantage I find with box2d is that their is no separation between the physics and collision detection systems so if you don't need every object to interact with every other object your going to waste a lot of cpu power filtering out useless collision infowhich sounds like I cant have various collision materials, eg objA == matA && objB == matA dont worry about colliding
Quote: Original post by zedz
Actually Im quite pleased as I dont have to spend time to integrate this into my game :)
Quote: I think Kaze was referring to the fact that you have to actually have an active, physical body as part of the world to test against with whatever minor overhead that involvesok like having a linesegmenttest for say particles
Quote: Mine goes more like this: Particles, Graphics, Physics, and lastly AI.the opposite to me, AI is top for me because X number of aliens have to pay attention to what other aliens are doing (boids) + when theres lots this can potentially become expensive (in fact I had to rewrite part of my scenegraph to deal with this)
Quote: Original post by EasilyConfused
Not at all - Box2D has a built in system (that can also be easily overridden if you need to) to specify collision filters. I think Kaze was referring to the fact that you have to actually have an active, physical body as part of the world to test against with whatever minor overhead that involves. Filtering to ignore collisions between different types objects is pretty easy.
Quote: Original post by KazeQuote: Original post by EasilyConfused
Not at all - Box2D has a built in system (that can also be easily overridden if you need to) to specify collision filters. I think Kaze was referring to the fact that you have to actually have an active, physical body as part of the world to test against with whatever minor overhead that involves. Filtering to ignore collisions between different types objects is pretty easy.
You can filter the collisions but I'm pretty sure filtering is all it is and it doesn't optimize the groups in any way.
for example if you 3 groups
A: for terrain
B: for creatures
C: for particle effects
where particles ignores bodies and both terrain and particles ignore other terrain and particles respectively
even if creating and filtering the collision info for one object is insignificant it not going to take long before
(A + B + C)^ 2
gets a lot bigger than
(A*B) + B^2+ (A*C)
Quote: I am wondering why you don't discuss this on the Box2D forum and prefer a more general place like GameDev.net instead.
