Basic test program

[perkins]

So I'm trying to get a basic test program to work, just a world with a single object that moves, using 64 bit linux. NewtonBodySetTransformCallback seems to work, the function I register with it gets called once an update. NewtonBodySetForceAndTorqueCallback does not seem to work. I notice it is commented out in some of the tutorials, has it been replaced? Or am I just not setting something up properly... Anyway, here is the code: http://pastebin.com/AaEPh6cm

compiled via
gcc $PWD/libNewton.so -o tst -lstdc++ -lpthread -lrt tst.c
run via
LD_LIBRARY_PATH=$PWD ./tst


It outputs

0
In transformCallback
1
In transformCallback
In transformCallback
In transformCallback
In transformCallback

Note that forceAndTorqueCallback does not get called.

Also, NewtonBodyGetForce and NewtonBodyGetVelocity give 0 for both the force and the velocity. I know I must be missing something obvious, but I would appreciate some pointers on what to do differently.

[perkins]

It seems that the body is going to seelp, even though autosleep is off. I do see that the NewtonBodySetForce only works from withint ForceAndTorqueCallback, but I still don't understand why the body is falling asleep without ever calling forceAndTorqueCallback and with autosleep off...

[JoeJ]

Sounds like you forgot to set the force tourque callback at body creation - NewtonBodySetForceAndTorqueCallback (body, funcPtr) ?
Thus no force, velocity and sleep.
For me turning off autosleep only works properly when i call it from within force tourque callback, otherwise obies ignored my setting and kept falling to sleep, which is confusing.

[Julio Jerez]

you created a kinematic body but you are using as if it was dynamic

Code: Select all

 NewtonWorld* world= NewtonCreate();
 NewtonCollision *collision=NewtonCreateBox(world, 10, 10, 10, 1, 0);
 NewtonBody *box=NewtonCreateKinematicBody(world, collision, matrix);
 NewtonBodySetMassMatrix(box, 1, 1, 1, 1);

kinematic bodies sleep 100% of the time because they are not part of the dynamics updates,
they only particulate on a dynamcis update as contact generators when other dynamic bodies collide with them.
try making it a body dynamics
NewtonBody *box=NewtonCreateDynmaicBody(world, collision, matrix);

[perkins]

Ah, that seems rather obvious now, and thanks Joe for mentioning the sleep only working from within the callback. I should be off and running now