[ODE] ODE is massively slow

[David McClurg]

put all your terrain geoms (the 16 boxes) in a geom "group" so they do not self-collide.

-----Original Message-----
From: Chris Brodie [mailto:Chris.Brodie@macquarie.com]
Sent: Friday, 31 January 2003 9:20 AM
To: 'ode@q12.org'
Subject: [ODE] ODE is massively slow


...now that I have your attention, on to the details.

I've just finished integrating ODE in to my engine. I have a number of problems, the most obvious is that with a simple test case of 16 static geomBox's. My ingame profiling system tells me that 60% of my games time is spent on :	

dSpaceCollide(m_Space, 0, &ProximityTest);

Of that 60% the proximity test measures 16%. The proximity test is essentially just what we have in the BuggyTest. My system is a 1.2g Celeron, 384mb 133 ram with a GF2. My build was debug running a release ODE.lib.

I have a terrain, as a simple test case, I decided to just place a geombox around each one and tumble a handful of cubes down the hill. Very primitive test. I'm not using any triangle collider at all yet. The terrain consists of 4 * 4 boxes of varying heights based on the terrain patch's extents. Therefore each box shares sides with other boxes. I didn't get as far as adding the dynamics objects.

Now since all objects are associated with the default space (0) I would asume that no collisions would be detected, but I get 136 calls to proximity test per second with an step rate of 0.05 (20fps).

The docs say:
"In other words, how can you create a body that doesn't move, but that interacts with other bodies? The answer is to create a geom only, without the corresponding rigid body object."
So to create my box's all I call is :

Terrain.cpp
NewTile->Geom = dCreateBox(CDynamics::GetInstance().GetSpace(), NewTile->BoundingBox.GetWidth(), NewTile->BoundingBox.GetHeight(), NewTile->BoundingBox.GetDepth());

I've check the coordinates, they don't overlap or anything, but as I see it, it's a static object and should be free from collision tests. I use a hash space created as follows:

Dynamics.cpp
m_Space = dHashSpaceCreate(0);
dHashSpaceSetLevels (m_Space, 2, 16);

Any idea's on why this is happening? From whats I've noticed inserting a static object in the world appears to produce the same amount of collision work as a geom linked to a body.

Many thanks,

Chris


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