def test_particle_birth_rate():
# Tests a system with a standard birth rate of 0.5, that it is
# indeed birthing at that rate. It serves as a control for the
# next test as well.
system = Particles("testSystem", 2)
system.set_render_parent(NodePath(PandaNode("test")))
system.set_spawn_render_node_path(NodePath(PandaNode("test")))
assert system.get_birth_rate() == 0.5
assert system.get_tics_since_birth() == 0
assert system.get_living_particles() == 0
system.update(0.6)
assert system.get_living_particles() == 1
system.update(0.5)
assert system.get_living_particles() == 2
# Should still be 2, since the pool size was 2.
system.update(0.5)
assert system.get_living_particles() == 2
def test_particle_soft_start():
# Create a particle effect and a particle system.
# The effect serves to test the Python-level "soft_start" method,
# while the system serves to test the C++-level "soft_start" method
# (via the associated Python "soft_start" method)
effect = ParticleEffect()
system = Particles("testSystem", 10)
# Setup some dummy nodes, since it seems to want them
system.set_render_parent(NodePath(PandaNode("test")))
system.set_spawn_render_node_path(NodePath(PandaNode("test")))
# Add the system to the effect
effect.add_particles(system)
# Re-assign the system, just to make sure that we have the
# right object.
system = effect.get_particles_list()[0]
# First, standard "soft_start"--i.e. without either changing
# the birth-rate or applying a delay. This should work as it
# used to.
effect.soft_start()
assert system.get_birth_rate() == 0.5
# Now, check that the pre-existing single-parameter soft-start,
# which alters the birth-rate, still does so.
system.soft_start(1)
assert system.get_birth_rate() == 1
# Next, birth-delaying.
# Run a standard soft-start, then check that the birth-timer
# is zero, as used to be the case on running this command.
effect.soft_start()
assert system.get_tics_since_birth() == 0
# Run an delayed soft-start via the system, then check that the
# birth-timer has the assigned value, and that the birth-rate is
# unchanged.
# (We pass in a birth-rate ("br") of -1 because the related code
# checks for a birth-rate greater than 0, I believe. This allows
# us to change the delay without affecting the birth-rate.)
system.soft_start(br=-1, first_birth_delay=-2)
assert system.get_birth_rate() == 1
assert system.get_tics_since_birth() == 2
# Now, run a delayed soft-start via the effect, and
# again check that the birth-timer has changed as intended,
# and the birth-rate hasn't changed at all.
effect.soft_start(firstBirthDelay=0.25)
assert system.get_birth_rate() == 1
assert system.get_tics_since_birth() == -0.25
# Update the system, advancing it far enough that it should
# have birthed a particle if not for the delay, but not
# so far that it should have birthed a particle >with<
# the delay. Check thus that no particles have been birthed.
system.update(1)
assert system.get_living_particles() == 0
# Update the system again, this time far enough that with the
# delay it should have birthed just one particle, and
# then check that this is the case.
system.update(1)
assert system.get_living_particles() == 1