prediction progress

src/common.h

@@ -488,7 +488,6 @@ struct string32 {
 };
 
 #define UID(hi, lo) (struct uid) { .v = U128((hi), (lo)) }
-#define UID0 (struct uid) { 0 }
 struct uid {
     union {
         u128 v;
@@ -499,6 +498,7 @@ struct uid {
     };
 };
 INLINE b32 uid_eq(struct uid a, struct uid b) { return u128_eq(a.v, b.v); }
+INLINE b32 uid_is_zero(struct uid uid) { return u128_eq(uid.v, U128(0, 0)); }
 
 struct image_rgba {
     u32 width;

src/sim.c

@@ -332,6 +332,8 @@ struct sim_snapshot *sim_snapshot_alloc(struct sim_client *client, struct sim_sn
         root->handle = SIM_ENT_ROOT_HANDLE;
         root->valid = true;
         root->is_root = true;
+        root->mass_unscaled = F32_INFINITY;
+        root->inertia_unscaled = F32_INFINITY;
         ++ss->num_ents_allocated;
         ++ss->num_ents_reserved;
     } else {

src/sim_ent.c

@@ -99,7 +99,7 @@ void sim_ent_release_raw(struct sim_ent *ent)
     }
 
     /* Release uid */
-    sim_ent_set_uid(ent, UID0);
+    sim_ent_set_uid(ent, UID(0, 0));
 
     /* Release */
     ++ent->handle.gen;
@@ -174,7 +174,7 @@ void sim_ent_set_uid(struct sim_ent *ent, struct uid uid)
     struct uid old_uid = ent->uid;
 
     /* Release old from lookup */
-    if (!uid_eq(old_uid, UID0)) {
+    if (!uid_is_zero(old_uid)) {
         u64 hash = hash_from_uid(old_uid);
         struct sim_ent_bucket *bucket = &buckets[hash % num_uid_buckets];
         struct sim_ent *prev = sim_ent_nil();
@@ -203,7 +203,7 @@ void sim_ent_set_uid(struct sim_ent *ent, struct uid uid)
     }
 
     /* Insert new uid into lookup */
-    if (!uid_eq(uid, UID0)) {
+    if (!uid_is_zero(uid)) {
         u64 hash = hash_from_uid(uid);
         struct sim_ent_bucket *bucket = &buckets[hash % num_uid_buckets];
         struct sim_ent *last = sim_ent_from_handle(ss, bucket->last);
@@ -223,7 +223,7 @@ struct sim_ent *sim_ent_from_uid(struct sim_snapshot *ss, struct uid uid)
 {
     struct sim_ent *res = sim_ent_nil();
     u64 num_buckets = ss->num_uid_buckets;
-    if (num_buckets > 0 && !uid_eq(uid, UID0)) {
+    if (num_buckets > 0 && !uid_is_zero(uid)) {
         u64 hash = hash_from_uid(uid);
         struct sim_ent_bucket *bucket = &ss->uid_buckets[hash % num_buckets];
         for (struct sim_ent *e = sim_ent_from_handle(ss, bucket->first); e->valid; e = sim_ent_from_handle(ss, e->next_in_uid_bucket)) {

src/sim_ent.h

@@ -387,6 +387,11 @@ INLINE b32 sim_ent_is_valid_and_active(struct sim_ent *ent)
     return ent->valid && sim_ent_has_prop(ent, SIM_ENT_PROP_ACTIVE);
 }
 
+INLINE b32 sim_ent_should_simulate(struct sim_ent *ent)
+{
+    return !sim_ent_has_prop(ent, SIM_ENT_PROP_SYNC_DST);
+}
+
 /* ========================== *
  * Ent functions
  * ========================== */