optimizations + bugfixes

* Bombs explode on damage/explosion
* Orbits spell fixed
* Performance: implemented shared component indexes,
compiled Lua caching, and updates only for changed projectile fields.
Also removed accumulating hidden entity slots.

src/gun/projectiles.cpp

@@ -24,6 +24,20 @@ constexpr double kDeg = 3.14159265358979323846 / 180.0;
 
 } // namespace
 
+std::string ProjectileSim::script_definition_key(const EntityDef& entity) {
+    std::string state = entity.tags;
+    for (const auto& c : entity.comps) {
+        state += c.type;
+        if (c.type == "VariableStorageComponent") continue;
+        for (const auto& [key, value] : c.attrs) {
+            // _ng_next and _ng_img_t are emitter clocks, not changes to its effect definition.
+            if (key.rfind("_ng_", 0) == 0 || key == "mWhoShot" || key == "mEntityThatShot" || key == "mShooterHerdId" || key.rfind("mVelocity", 0) == 0) continue;
+            state += key + "=" + value + ";";
+        }
+    }
+    return entity.path + "#script" + std::to_string(std::hash<std::string>()(state));
+}
+
 const ProjDef* ProjectileSim::def(const std::string& file) {
     auto it = defs_.find(file);
     if (it != defs_.end()) return &it->second;
@@ -41,6 +55,7 @@ void ProjectileSim::disable_gpu_lua() {
 
 // The entity has components the GPU does not simulate (CellEater, MagicConvertMaterial, area effects, scripts...): the host keeps a runtime twin of the projectile
 static bool host_runs(const EntityDef& e, bool gpu_script = false) {
+    if (!e.all("DamageModelComponent").empty()) return true;
     for (const char* rich : {"CellEaterComponent", "MagicConvertMaterialComponent", "GameAreaEffectComponent", "AreaDamageComponent", "LightningComponent", "LaserEmitterComponent", "MaterialSeaSpawnerComponent", "TeleportProjectileComponent", "EnergyShieldComponent", "ExplosionComponent", "LooseGroundComponent", "ArcComponent", "LightningComponent", "BlackHoleComponent", "MaterialSuckerComponent"})
         if (!e.all(rich).empty()) return true;
     if (!gpu_script) for (const EntityComponent* lc : e.all("LuaComponent")) for (const auto& kv : lc->attrs) if (kv.first.rfind("script_", 0) == 0 && !kv.second.empty()) return true;
@@ -94,7 +109,11 @@ const ProjDef* ProjectileSim::def_from(const std::string& file, const EntityDef&
     std::istringstream tags(entity.tags);std::string tag;
     while(std::getline(tags,tag,',')) {
         auto begin=tag.find_first_not_of(' '), end=tag.find_last_not_of(' ');
-        if(begin!=std::string::npos&&tag.substr(begin,end-begin+1)=="projectile")d.query_projectile=true;
+        if(begin!=std::string::npos) {
+            const auto token = tag.substr(begin,end-begin+1);
+            if(token=="projectile")d.query_projectile=true;
+            if(token=="orbit_projectile")d.orbiting=true;
+        }
     }
     unsigned velocity_count=0;
     for(const auto* component:entity.all("VelocityComponent"))if(component->get("_enabled","1")!="0")++velocity_count;
@@ -160,6 +179,11 @@ const ProjDef* ProjectileSim::def_from(const std::string& file, const EntityDef&
         d.friendly_fire = attr(pc, "friendly_fire", 0) != 0;
         d.dont_hit_player = attr(pc, "dont_hit_player", 0) != 0;
         d.collide_with_shooter_frames = (int)attr(pc, "collide_with_shooter_frames", -1);   // (-1: never hits its shooter)
+        if (d.orbiting) {
+            d.friendly_fire = true;
+            d.dont_hit_player = false;
+            d.collide_with_shooter_frames = 6;
+        }
         d.physics = !e->all("PhysicsBodyComponent").empty();
         if (d.physics) d.on_collision_die = false;
         d.explode_on_death = attr(pc, "on_death_explode", 0) != 0 || attr(pc, "on_lifetime_out_explode", 0) != 0;