def test_ConstructionInfo_to_RigidBody(self):
"""
Verify that the initial motion state is transferred correctly to the
RigidBody.
"""
mass = 10
pos = Vec3(1, 2, 3)
rot = Quaternion(0, 1, 0, 0)
t = Transform(rot, pos)
ms = DefaultMotionState(t)
cs = EmptyShape()
inert = Vec3(1, 2, 4)
# Compile the Rigid Body parameters.
ci = RigidBodyConstructionInfo(mass, ms, cs, Vec3(2, 4, 6))
assert ci.localInertia == Vec3(2, 4, 6)
ci.localInertia = inert
assert ci.localInertia == inert
# Construct the rigid body and delete the construction info.
body = RigidBody(ci)
del ci
# Verify that the object is at the correct position and has the correct
# mass and inertia.
t = body.getMotionState().getWorldTransform()
assert t.getOrigin() == pos
assert t.getRotation() == rot
assert body.getInvMass() == 1 / mass
assert body.getInvInertiaDiagLocal() == Vec3(1, 0.5, 0.25)
def getRB(pos=Vec3(0, 0, 0), cshape=SphereShape(1), bodyID=0):
"""
Return a Rigid Body plus auxiliary information (do *not* delete; see
note below).
.. note:: Do not delete the tuple until the end of the test
because it may lead to memory access violations. The reason is that a
rigid body requires several indepenent structures that need to remain
in memory.
"""
t = Transform(Quaternion(0, 0, 0, 1), pos)
ms = DefaultMotionState(t)
mass = 1
# Build construction info and instantiate the rigid body.
ci = RigidBodyConstructionInfo(mass, ms, cshape)
rb = RigidBody(ci, bodyID)
# Ensure the body remains activated.
rb.forceActivationState(4)
return rb
def getRB(pos=Vec3(0, 0, 0), cshape=SphereShape(1)):
"""
Return a Rigid Body plus auxiliary information (do *not* delete; see
note below).
.. note:: Do not delete the tuple until the end of the test
because it may lead to memory access violations. The reason is that a
rigid body requires several indepenent structures that need to remain
in memory.
"""
t = Transform(Quaternion(0, 0, 0, 1), pos)
ms = DefaultMotionState(t)
mass = 1
# Build construction info and instantiate the rigid body.
ci = RigidBodyConstructionInfo(mass, ms, cshape)
return RigidBody(ci)
def runSimulation(sim):
# Create the collision shapes for the ball and ground.
cs_ball = SphereShape(1)
cs_ground = StaticPlaneShape(Vec3(0, 1, 0), 1)
# Create a Rigid Body for the static (ie mass=0) Ground.
q0 = Quaternion(0, 0, 0, 1)
ms = DefaultMotionState(Transform(q0, Vec3(0, -1, 0)))
ci = RigidBodyConstructionInfo(0, ms, cs_ground)
rb_ground = RigidBody(ci, bodyID=1)
del ms, ci
# Create a Rigid body for the dynamic (ie mass > 0) Ball.
ms = DefaultMotionState(Transform(q0, Vec3(0, 5, 0)))
inertia = cs_ball.calculateLocalInertia(1)
ci = RigidBodyConstructionInfo(1, ms, cs_ball, inertia)
rb_ball = RigidBody(ci, bodyID=2)
del ms, inertia, ci
# Ensure that Bullet never deactivates the objects.
rb_ground.forceActivationState(4)
rb_ball.forceActivationState(4)
# Add both bodies to the simulation.
sim.addRigidBody(rb_ground)
sim.addRigidBody(rb_ball)
# Sanity check: the ball must be at position y=5
pos = rb_ball.getMotionState().getWorldTransform().getOrigin()
pos = pos.topy()
assert pos[1] == 5
# Step the simulation long enough for the ball to fall down and
# come to rest on the plane.
for ii in range(10):
sim.stepSimulation(1, 100)
# Verify that the y-position of the ball is such that the ball
# rests on the plane.
pos = rb_ball.getMotionState().getWorldTransform().getOrigin()
return pos.topy()
from azBullet import DefaultMotionState, Transform
from azBullet import RigidBody, RigidBodyConstructionInfo
sim = azBullet.BulletBase()
sim.setGravity(Vec3(0, -10, 0))
# Create a collision shape for the Ball and for the Ground.
ballShape = SphereShape(1)
groundShape = StaticPlaneShape(Vec3(0, 1, 0), 1)
# Create a Rigid Body for the Ground based on the collision shape.
mass = 0
groundRigidBodyState = DefaultMotionState(
Transform(Quaternion(0, 0, 0, 1), Vec3(0, -1, 0)))
ci = RigidBodyConstructionInfo(mass, groundRigidBodyState, groundShape)
groundRigidBody = RigidBody(ci)
groundRigidBody.setRestitution(1.0)
sim.addRigidBody(groundRigidBody)
del mass, ci
# Create a Rigid body for the Ball based on its collision shape. Let Bullet do
# the heavy lifting and compute the mass and inertia for us.
fallRigidBodyState = DefaultMotionState(
Transform(Quaternion(0, 0, 0, 1), Vec3(0, 20, 0)))
mass = 1
fallInertia = ballShape.calculateLocalInertia(mass)
ci = RigidBodyConstructionInfo(
mass, fallRigidBodyState, ballShape, fallInertia)
fallRigidBody = RigidBody(ci)
fallRigidBody.setRestitution(0.5)
sim.addRigidBody(fallRigidBody)
inertia, principal = cs.calculatePrincipalAxisTransform(masses)
print('\nCenter of Mass: ', principal.getOrigin().topy())
print('Inertia Values: ', inertia)
print('Inertia Principal Axis: ', principal.getRotation().topy())
del t1, t2, csSphere
# Construct the rigid body for the compound shape based on the just computed
# inertia tensor.
print('\nTotal Mass: {}'.format(sum(masses)))
ci = azBullet.RigidBodyConstructionInfo(
sum(masses),
azBullet.DefaultMotionState(principal),
cs,
inertia,
)
body = RigidBody(ci)
# Add the body with its compound shape to the simulation.
sim.addRigidBody(body)
del masses, ci
# Apply an initial force and torque (only valid for the first simulation step
# because Bullet will clear all the forces afterwards).
body.clearForces()
body.applyCentralForce(Vec3(*(0, 1, 0)))
# body.applyTorque(Vec3(*(0, 1, 0)))
# Step the simulation and print the position of the Ball.
for ii in range(10):
wt = body.getMotionState().getWorldTransform()
pos = wt.getOrigin().topy()
# Instantiate the Bullet simulation.
sim = azBullet.BulletBase()
sim.setGravity(Vec3(0, -10, 0))
# Create the collision shape for Ball and Ground.
ballShape = SphereShape(1)
groundShape = StaticPlaneShape(Vec3(0, 1, 0), 1)
# Create the rigid body for the Ground. Since it is a static body its mass must
# be zero.
mass = 0
groundRigidBodyState = DefaultMotionState(
Transform(Quaternion(0, 0, 0, 1), Vec3(0, -1, 0)))
ci = RigidBodyConstructionInfo(mass, groundRigidBodyState, groundShape)
groundRigidBody = RigidBody(ci)
groundRigidBody.setRestitution(1.0)
sim.addRigidBody(groundRigidBody)
del mass, ci
# Create the rigid body for the Ball. Since it is a dynamic body we need to
# specify mass and inertia. The former we need to do ourselves but Bullet can
# do the heavy lifting for the Inertia and compute it for us.
fallRigidBodyState = DefaultMotionState(
Transform(Quaternion(0, 0, 0, 1), Vec3(0, 20, 0)))
mass = 1
fallInertia = ballShape.calculateLocalInertia(mass)
ci = RigidBodyConstructionInfo(mass, fallRigidBodyState, ballShape,
fallInertia)
fallRigidBody = RigidBody(ci)
fallRigidBody.setRestitution(0.5)
