Particle trajectory smoothing: where to do the simulation?
- by nkint
I have a particle system in which I have particles that are moving to a target and the new targets are received via network. The list of new target are some noisy coordinates of a moving target stored in the server that I want to smooth in the client.
For doing the smoothing and the particle I wrote a simple particle engine with standard euler integration model.
So, my pseudo code is something like that:
# pseudo code
class Particle:
def update():
# do euler motion model integration:
# if the distance to the target is more than a limit
# add a new force to the accelleration
# seeking the target,
# and add the accelleration to velocity
# and velocity to the position
positionHistory.push_back(position);
if history.length > historySize :
history.pop_front()
class ParticleEngine:
particleById = dict() # an associative array
# where the keys are the id
# and particle istances are sotred as values
# this method is called each time a new tcp packet is received and parsed
def setNetTarget(int id, Vec2D new_target):
particleById[id].setNewTarget(new_target)
# this method is called each new frame
def draw():
for p in particleById.values:
p.update()
beginVertex(LINE_STRIP)
for v in p.positionHistory:
vertex(v.x, v.y)
endVertex()
The new target that are arriving are noisy but setting some accelleration/velocity parameters let the particle to have a smoothed trajectories.
But if a particle trajectory is a circle after a while the particle position converge to the center (a normal behaviour of euler integration model).
So I decided to change the simulation and use some other interpolation (spline?) or smooth method (kalman filter?) between the targets. Something like:
switch( INTERPOLATION_MODEL ):
case EULER_MOTION: ...
case HERMITE_INTERPOLATION: ...
case SPLINE_INTERPOLATION: ...
case KALMAN_FILTER_SMOOTHING: ...
Now my question: where to write the motion simulation / trajectory interpolation? In the Particle? So I will have some Particle subclass like ParticleEuler, ParticleSpline, ParticleKalman, etc..? Or in the particle engine?
