problem with Bullet in latest build

Compiling or Editing the Panda Source
1

I built panda today with this command

makepanda/makepanda.py --verbose --everything --threads 6 --optimize 3 --installer --no-ffmpeg --no-fftw --use-bullet

But when running this sample (from manual) python code

import direct.directbase.DirectStart
from panda3d.core import Vec3
from panda3d.bullet import BulletWorld
from panda3d.bullet import BulletPlaneShape
from panda3d.bullet import BulletRigidBodyNode
from panda3d.bullet import BulletBoxShape
 
base.cam.setPos(0, -10, 0)
base.cam.lookAt(0, 0, 0)
 
# World
world = BulletWorld()
world.setGravity(Vec3(0, 0, -9.81))
 
# Plane
shape = BulletPlaneShape(Vec3(0, 0, 1), 1)
node = BulletRigidBodyNode('Ground')
node.addShape(shape)
np = render.attachNewNode(node)
np.setPos(0, 0, -2)
world.attachRigidBody(node)
 
# Box
shape = BulletBoxShape(Vec3(0.5, 0.5, 0.5))
node = BulletRigidBodyNode('Box')
node.setMass(1.0)
node.addShape(shape)
np = render.attachNewNode(node)
np.setPos(0, 0, 2)
world.attachRigidBody(node)
model = loader.loadModel('models/box.egg')
model.flattenLight()
model.reparentTo(np)
 
# Update
def update(task):
  dt = globalClock.getDt()
  world.doPhysics(dt)
  return task.cont
 
taskMgr.add(update, 'update')
base.run()

the box is freezed without falling.
The last time I built panda (on 2015-03-21, commit ba65298) all worked fine.

2

I use the 1.9.0 official build so my solution may not apply to your case.

I had a similar issue (Bullet objects were not moving whereas they were in 1.8.1 with the same code) and I found out that I should update the Bullet world by defining substeps in 1.9.0 :

So instead of : world.doPhysics(dt), try : world.doPhysics(dt, 5, 1.0/180.0)

3

I just checked in a fix - it was a problem in calculating the default values of arguments in the Python bindings. The workaround is to explicitly specify the values, like doPhysics(dt, 1, 1.0/60.0) (the defaults).

Thanks to both!