void
plStepParticleSystem(PLparticles *ps, float dt)
{
assert(ps != NULL);
if (ps->enabled == false) return;
size_t activeParticles = 0;
for (size_t i = 0 ; i < ps->particleCount ; ++i) {
if (ps->particles[i].active) {
ps->particles[i].p += vf3_s_mul(ps->particles[i].v, dt) + vf3_s_mul(ps->obj->v, dt);
ps->particles[i].age += dt;
activeParticles++;
if (ps->particles[i].age > ps->particles[i].lifeTime) {
ps->particles[i].active = false;
int_array_push(&ps->freeParticles, i);
activeParticles --;
}
}
}
// Auto disable
if (ps->autoDisable) {
if (activeParticles == 0) {
ps->enabled = false;
}
return;
}
// Not off or disabled, emitt new particles
float newPartCount = ps->emissionRate * dt * (1.0 + rand_percent(10));
float intPart;
float frac = modff(newPartCount, &intPart);
unsigned newParticles = (unsigned) intPart;
// The fraction is handled with randomisation
int rval = random() % 128;
if ((float)rval/128.0f < frac) newParticles ++;
for (unsigned i = 0 ; i < newParticles ; ++i) {
if (ps->freeParticles.length > 0) {
int i = int_array_remove(&ps->freeParticles, 0);
ps->particles[i].active = true;
ps->particles[i].age = 0.0;
// Adjust lifetime by +-20 %
ps->particles[i].lifeTime = ps->lifeTime + ps->lifeTime * rand_percent(20);
ps->particles[i].p = v_q_rot(ps->p, ps->obj->q);
ps->particles[i].v = v_q_rot(ps->v * vf3_set(rand_percent(10), rand_percent(10), rand_percent(10)), ps->obj->q);
ps->particles[i].rgb = ps->rgb;
} else {
break;
}
}
}
float3
pl_compute_gravity(pl_astrobody_t *a, pl_object_t *b)
{
float3 dist = lwc_dist(&b->p, &a->obj.p);
double r12 = vf3_abs_square(dist);
float3 ndist = vf3_normalise(dist);
float3 f12 = vf3_s_mul(ndist,
//-PL_G * (a->obj.m.m * b->m.m / r12));
-a->GM * b->m.m / r12);
assert(isfinite(dist.x));
assert(isfinite(dist.y));
assert(isfinite(dist.z));
assert(isfinite(ndist.x));
assert(isfinite(ndist.y));
assert(isfinite(ndist.z));
assert(isfinite(r12));
assert(isfinite(f12.x));
assert(isfinite(f12.y));
assert(isfinite(f12.z));
return f12;
}
void
pl_sys_update_current_pos(pl_system_t *sys, double dt)
{
if (sys->parent) {
double t = sim_time_get_jd();
if (sys->orbitalBody->tUpdate > 0) {
lwc_translate3fv(&sys->orbitalBody->obj.p,
vf3_s_mul(sys->orbitalBody->obj.v, dt));
sys->orbitalBody->tUpdate --;
} else {
float3 newPos = plOrbitPosAtTime(sys->orbitalBody->kepler,
sys->parent->orbitalBody->GM,
t*PL_SEC_PER_DAY);
float3 nextPos = plOrbitPosAtTime(sys->orbitalBody->kepler,
sys->parent->orbitalBody->GM,
t*PL_SEC_PER_DAY + (double)sys->orbitalBody->orbitFixationPeriod * dt);
float3 vel = vf3_s_div(vf3_sub(nextPos, newPos),
(double)sys->orbitalBody->orbitFixationPeriod * dt);
sys->orbitalBody->obj.p = sys->parent->orbitalBody->obj.p;
lwc_translate3fv(&sys->orbitalBody->obj.p, newPos);
sys->orbitalBody->obj.v = sys->parent->orbitalBody->obj.v + vel;
// Reset tUpdate;
sys->orbitalBody->tUpdate = sys->orbitalBody->orbitFixationPeriod;
}
sys->orbitalBody->obj.q = plSideralRotationAtTime(sys->orbitalBody, t);
} else {
lwc_set(&sys->orbitalBody->obj.p, 0.0, 0.0, 0.0);
}
}
void
plMassRotateQ(PLmass *m, quaternion_t q)
{
float3x3 mat;
q_mf3_convert(mat, q);
plMassRotateM(m, mat);
}
void
plMassAdd(PLmass * restrict md, const PLmass * restrict ms)
{
float recip = 1.0f / (md->m + ms->m);
float3 a = vf3_s_mul(md->cog, md->m);
float3 b = vf3_s_mul(ms->cog, ms->m);
float3 c = vf3_add(a, b);
md->cog = vf3_s_mul(c, recip);
md->m += ms->m;
for (int i = 0 ; i < 3 ; ++ i) {
md->I[i] = vf3_add(md->I[i], ms->I[i]);
}
mf3_inv2(md->I_inv, md->I);
}
void
plMassMod(PLmass *m, float newMass)
{
