void update_particle(int i) {
if(tinymt32_generate_float01(&rndstate) < 0.4F) {
particles[i].dx += random_in_rangef(-JITTER, JITTER);
particles[i].dy += random_in_rangef(-JITTER, JITTER);
}
// gravitate towards goal
particles[i].dx += -(particles[i].position.x - particles[i].grav_center.x)/particles[i].power;
particles[i].dy += -(particles[i].position.y - particles[i].grav_center.y)/particles[i].power;
// stop swarming if goal reached
if (particles[i].swarming) {
float dx, dy;
dx = particles[i].position.x - particles[i].grav_center.x;
dy = particles[i].position.y - particles[i].grav_center.y;
if (((dx*dx)+(dy*dy)) < GOAL_DISTANCE) {
particles[i].swarming = false;
}
}
// damping
particles[i].dx *= 0.999F;
particles[i].dy *= 0.999F;
// snap to max
float speed;
if (particles[i].swarming)
speed = SWARM_SPEED;
else
speed = MAX_SPEED;
if(particles[i].dx > speed) particles[i].dx = speed;
if(particles[i].dx < -speed) particles[i].dx = -speed;
if(particles[i].dy > speed) particles[i].dy = speed;
if(particles[i].dy < -speed) particles[i].dy = -speed;
particles[i].position.x += particles[i].dx;
particles[i].position.y += particles[i].dy;
// update size
// when we're showing the time, don't blink like you normally would
if(showing_time == 0) {
if((abs(particles[i].size - MIN_SIZE) < 0.001F) && (tinymt32_generate_float01(&rndstate) < 0.0008F)) {
particles[i].goal_size = MAX_SIZE;
}
if(abs(particles[i].size - MAX_SIZE) < 0.001F) {
particles[i].goal_size = MIN_SIZE;
}
}
particles[i].ds += -(particles[i].size - particles[i].goal_size)/random_in_rangef(1000.0F, 5000.0F);
if(abs(particles[i].size - particles[i].goal_size) > 0.01) {
particles[i].size += particles[i].ds;
}
if(particles[i].size > MAX_SIZE) particles[i].size = MAX_SIZE;
if(particles[i].size < MIN_SIZE) particles[i].size = MIN_SIZE;
}
float
nv_rand(void)
{
int thread_id = nv_omp_thread_id();
NV_ASSERT(thread_id < NV_RAND_THREAD_MAX);
return tinymt32_generate_float01(&g_state[thread_id]);
}
float random_in_rangef(float min, float max) {
return min + (float)(tinymt32_generate_float01(&rndstate) * ((max - min)));
}
int random_in_range(int min, int max) {
return min + (int)(tinymt32_generate_float01(&rndstate) * ((max - min) + 1));
}
