/// \param elapsedTime Amount of time that has elapsed (in seconds) since last update
void ParticleEffect::update(float elapsedTime)
{
m_fElapsedTime = elapsedTime; // store time in class composition in case
// other update functions need it
killParticles(); // cull old particles
birthParticles(); // create new particles
for(int i=0; i<m_nLiveParticleCount; i++)
{
Particle *part = &(m_Particles[m_drawOrder[i]]);
// Here we use v = v + gt - vdt where v is velocity, g is gravity and d is
// drag. This is a bad approximation but it works.
// We also use p = p + vt, again this is a bad approximation, but fast
part->velocity +=
(m_vecGravity - part->velocity * part->drag) * m_fElapsedTime;
part->position += part->velocity * m_fElapsedTime;
}
// call additional update functions
for(UpdateFuncIter iter = m_UpdateFunc.begin(); iter != m_UpdateFunc.end(); iter++)
{
(*this.*(*iter))(); // really ugly looking code to call all relevant update functions
}
}
void ParticleField::Update() {
updateForces();
updateParticles();
killParticles();
spawnParticles();
}
