SimpleEmitterUpdate.cpp

void SimpleEmitter::update( const float dt )
{
	for ( uint i = 0 ; i < this->particles.size() ; ++i )
	{
		// subtract from the particles lifetime
		this->particles[i].lifetime -= dt;

		// if the lifetime is below 0 respawn the particle
		if ( this->particles[i].lifetime <= 0.0f )
		{
			this->particles[i].position = lstd_random_between( vec3( -1.0f ) , vec3( 1.0f ) );
			this->particles[i].lifetime = lstd_random_between( 1.0f , 2.0f );
		}

		// move the particle down depending on the delta time
		this->particles[i].position -= vec3( 0.0f , dt*2.0f , 0.0f );

		// update the position buffer
		this->positions[i*4+0] = this->particles[i].position[0];
		this->positions[i*4+1] = this->particles[i].position[1];
		this->positions[i*4+2] = this->particles[i].position[2];
		this->positions[i*4+3] = this->particles[i].lifetime;
	}
}