void ParticleEmitter::update(float elapsedTime)
{
if (!isActive())
{
return;
}
// Calculate the time passed since last update.
float elapsedSecs = elapsedTime * 0.001f;
if (_started && _emissionRate)
{
// Calculate how much time has passed since we last emitted particles.
_timeRunning += elapsedTime;
// How many particles should we emit this frame?
GP_ASSERT(_timePerEmission);
unsigned int emitCount = (unsigned int)(_timeRunning / _timePerEmission);
if (emitCount)
{
if ((int)_timePerEmission > 0)
{
_timeRunning = fmod(_timeRunning, (double)_timePerEmission);
}
emitOnce(emitCount);
}
}
GP_ASSERT(_node && _node->getScene() && _node->getScene()->getActiveCamera());
const Frustum& frustum = _node->getScene()->getActiveCamera()->getFrustum();
// Now update all currently living particles.
GP_ASSERT(_particles);
for (unsigned int particlesIndex = 0; particlesIndex < _particleCount; ++particlesIndex)
{
Particle* p = &_particles[particlesIndex];
p->_energy -= elapsedTime;
if (p->_energy > 0L)
{
if (p->_rotationSpeed != 0.0f && !p->_rotationAxis.isZero())
{
Matrix::createRotation(p->_rotationAxis, p->_rotationSpeed * elapsedSecs, &_rotation);
_rotation.transformPoint(p->_velocity, &p->_velocity);
_rotation.transformPoint(p->_acceleration, &p->_acceleration);
}
// Particle is still alive.
p->_velocity.x += p->_acceleration.x * elapsedSecs;
p->_velocity.y += p->_acceleration.y * elapsedSecs;
p->_velocity.z += p->_acceleration.z * elapsedSecs;
p->_position.x += p->_velocity.x * elapsedSecs;
p->_position.y += p->_velocity.y * elapsedSecs;
p->_position.z += p->_velocity.z * elapsedSecs;
if (!frustum.intersects(p->_position))
{
p->_visible = false;
continue;
}
p->_angle += p->_rotationPerParticleSpeed * elapsedSecs;
// Simple linear interpolation of color and size.
float percent = 1.0f - ((float)p->_energy / (float)p->_energyStart);
p->_color.x = p->_colorStart.x + (p->_colorEnd.x - p->_colorStart.x) * percent;
p->_color.y = p->_colorStart.y + (p->_colorEnd.y - p->_colorStart.y) * percent;
p->_color.z = p->_colorStart.z + (p->_colorEnd.z - p->_colorStart.z) * percent;
p->_color.w = p->_colorStart.w + (p->_colorEnd.w - p->_colorStart.w) * percent;
p->_size = p->_sizeStart + (p->_sizeEnd - p->_sizeStart) * percent;
// Handle sprite animations.
if (_spriteAnimated)
{
if (!_spriteLooped)
{
// The last frame should finish exactly when the particle dies.
float percentSpent = 0.0f;
for (unsigned int i = 0; i < p->_frame; i++)
{
percentSpent += _spritePercentPerFrame;
}
p->_timeOnCurrentFrame = percent - percentSpent;
if (p->_frame < _spriteFrameCount - 1 &&
p->_timeOnCurrentFrame >= _spritePercentPerFrame)
{
++p->_frame;
}
}
else
{
// _spriteFrameDurationSecs is an absolute time measured in seconds,
// and the animation repeats indefinitely.
p->_timeOnCurrentFrame += elapsedSecs;
if (p->_timeOnCurrentFrame >= _spriteFrameDurationSecs)
{
p->_timeOnCurrentFrame -= _spriteFrameDurationSecs;
++p->_frame;
if (p->_frame == _spriteFrameCount)
{
p->_frame = 0;
}
}
}
}
}
else
{
// Particle is dead. Move the particle furthest from the start of the array
// down to take its place, and re-use the slot at the end of the list of living particles.
if (particlesIndex != _particleCount - 1)
{
_particles[particlesIndex] = _particles[_particleCount - 1];
}
--_particleCount;
}
}
}
void ParticleEmitter::update(float elapsedTime)
{
if (!isActive())
return;
// Cap particle updates at a maximum rate. This saves processing
// and also improves precision since updating with very small
// time increments is more lossy.
static double runningTime = 0;
runningTime += elapsedTime;
if (runningTime < PARTICLE_UPDATE_RATE_MAX)
return;
float elapsedMs = runningTime;
runningTime = 0;
float elapsedSecs = elapsedMs * 0.001f;
if (_started && _emissionRate)
{
// Calculate how much time has passed since we last emitted particles.
_emitTime += elapsedMs; //+= elapsedTime;
// How many particles should we emit this frame?
GP_ASSERT(_timePerEmission);
unsigned int emitCount = (unsigned int)(_emitTime / _timePerEmission);
if (emitCount)
{
if ((int)_timePerEmission > 0)
{
_emitTime = fmod((double)_emitTime, (double)_timePerEmission);
}
emitOnce(emitCount);
}
}
// Now update all currently living particles.
GP_ASSERT(_particles);
for (unsigned int particlesIndex = 0; particlesIndex < _particleCount; ++particlesIndex)
{
Particle* p = &_particles[particlesIndex];
p->_energy -= elapsedMs;
if (p->_energy > 0L)
{
if (p->_rotationSpeed != 0.0f && !p->_rotationAxis.isZero())
{
Matrix::createRotation(p->_rotationAxis, p->_rotationSpeed * elapsedSecs, &_rotation);
_rotation.transformPoint(p->_velocity, &p->_velocity);
_rotation.transformPoint(p->_acceleration, &p->_acceleration);
}
// Particle is still alive.
p->_velocity.x += p->_acceleration.x * elapsedSecs;
p->_velocity.y += p->_acceleration.y * elapsedSecs;
p->_velocity.z += p->_acceleration.z * elapsedSecs;
p->_position.x += p->_velocity.x * elapsedSecs;
p->_position.y += p->_velocity.y * elapsedSecs;
p->_position.z += p->_velocity.z * elapsedSecs;
p->_angle += p->_rotationPerParticleSpeed * elapsedSecs;
// Simple linear interpolation of color and size.
float percent = 1.0f - ((float)p->_energy / (float)p->_energyStart);
p->_color.x = p->_colorStart.x + (p->_colorEnd.x - p->_colorStart.x) * percent;
p->_color.y = p->_colorStart.y + (p->_colorEnd.y - p->_colorStart.y) * percent;
p->_color.z = p->_colorStart.z + (p->_colorEnd.z - p->_colorStart.z) * percent;
p->_color.w = p->_colorStart.w + (p->_colorEnd.w - p->_colorStart.w) * percent;
p->_size = p->_sizeStart + (p->_sizeEnd - p->_sizeStart) * percent;
// Handle sprite animations.
if (_spriteAnimated)
{
if (!_spriteLooped)
{
// The last frame should finish exactly when the particle dies.
float percentSpent = 0.0f;
for (unsigned int i = 0; i < p->_frame; i++)
{
percentSpent += _spritePercentPerFrame;
}
p->_timeOnCurrentFrame = percent - percentSpent;
if (p->_frame < _spriteFrameCount - 1 &&
p->_timeOnCurrentFrame >= _spritePercentPerFrame)
{
++p->_frame;
}
}
else
{
// _spriteFrameDurationSecs is an absolute time measured in seconds,
// and the animation repeats indefinitely.
p->_timeOnCurrentFrame += elapsedSecs;
if (p->_timeOnCurrentFrame >= _spriteFrameDurationSecs)
{
p->_timeOnCurrentFrame -= _spriteFrameDurationSecs;
++p->_frame;
if (p->_frame == _spriteFrameCount)
{
p->_frame = 0;
}
}
}
}
}
else
{
// Particle is dead. Move the particle furthest from the start of the array
// down to take its place, and re-use the slot at the end of the list of living particles.
if (particlesIndex != _particleCount - 1)
{
_particles[particlesIndex] = _particles[_particleCount - 1];
}
--_particleCount;
}
}
}
