void
psNewParticle(PSparticle* p, float dt)
{
if (type == PS_WATERFALL) {
p->velocity[0] = -2*(drand48()-0.0);
p->velocity[1] = 0;
p->velocity[2] = 0.5*(drand48()-0.0);
p->position[0] = 0;
p->position[1] = 2;
p->position[2] = 0;
p->previous[0] = p->position[0];
p->previous[1] = p->position[1];
p->previous[2] = p->position[2];
p->dampening = 0.45*drand48();
p->alive = 1;
} else if (type == PS_FOUNTAIN) {
p->velocity[0] = 2*(drand48()-0.5);
p->velocity[1] = 5;
p->velocity[2] = 2*(drand48()-0.5);
p->position[0] = -0.1;
p->position[1] = 0.9;
p->position[2] = 0;
p->previous[0] = p->position[0];
p->previous[1] = p->position[1];
p->previous[2] = p->position[2];
p->dampening = 0.35*drand48();
p->alive = 1;
}
psTimeStep(p, 2*dt*drand48());
}
void
idle(void)
{
static int i, j;
static int living = 0; /* index to end of live particles */
static float dt;
static float last = 0;
dt = timedelta();
frame_time += dt;
#if 1
/* slow the simulation if we can't keep the frame rate up around
10 fps */
if (dt > 0.1) {
slow_down = 1.0/(100*dt);
} else if (dt < 0.1) {
slow_down = 1;
}
#endif
dt *= slow_down;
/* resurrect a few particles */
for (i = 0; i < flow*dt; i++) {
psNewParticle(&particles[living], dt);
living++;
if (living >= num_particles)
living = 0;
}
for (i = 0; i < num_particles; i++) {
psTimeStep(&particles[i], dt);
/* collision with sphere? */
if (draw_spheres) {
for (j = 0; j < draw_spheres; j++) {
psCollideSphere(&particles[i], &spheres[j]);
}
}
/* collision with ground? */
if (particles[i].position[1] <= 0) {
psBounce(&particles[i], dt);
}
/* dead particle? */
if (particles[i].position[1] < 0.1 &&
fequal(particles[i].velocity[1], 0)) {
particles[i].alive = 0;
}
}
glutPostRedisplay();
}
void
psNewParticle(PSparticle* p, float dt)
{
if (type == PS_WATERFALL) {
p->velocity[0] = -2*(drand48()-0.0);
p->velocity[1] = 0;
p->velocity[2] = 0.5*(drand48()-0.0); //presetting the particle with certain speed in x and z coods. Y cood is handled by gravity (above func)
p->position[0] = 0; //setting arbitary position
p->position[1] = 2;
p->position[2] = 0;
p->previous[0] = p->position[0];
p->previous[1] = p->position[1];
p->previous[2] = p->position[2];
p->dampening = 0.45*drand48();
p->alive = 1;
}
psTimeStep(p, 2*dt*drand48()); // giving "gravity" by specifying the gravity in Y cood
}
