/* * 2D Game Engine * ECS.cpp: * Based on pikuma.com 2D game engine in C++ and Lua course * Copyright (c) 2021 986-Studio. All rights reserved. * * Created by Manoƫl Trapier on 11/02/2021. */ #include #include #include /* Entity */ uint32_t IComponent::nextId = 0; /* TODO: this should be moved to the header file for optimisation purposes */ uint32_t Entity::getId() const { return this->id; } void Entity::kill() { this->registry->killEntity(*this); } void Entity::tag(const std::string &tag) { this->registry->tagEntity(*this, tag); } bool Entity::hasTag(const std::string &tag) const { return this->registry->entityHasTag(*this, tag); } void Entity::group(const std::string &groupName) { this->registry->groupEntity(*this, groupName); } bool Entity::belongsToGroup(const std::string &groupName) const { return this->registry->entityBelongsToGroup(*this, groupName); } /* System */ void System::addEntity(Entity entity) { this->entities.push_back(entity); } void System::removeEntity(Entity entity) { this->entities.erase(std::remove_if(this->entities.begin(), this->entities.end(), [&entity](Entity other) { return other.getId() == entity.getId(); }), this->entities.end()); } std::vector System::getSystemEntities() const { return this->entities; } const Signature& System::getComponentSignature() const { return this->componentSignature; } Entity Registry::createEntity() { uint32_t entityId; if (this->freeIds.empty()) { entityId = this->numEntities++; } else { entityId = this->freeIds.front(); this->freeIds.pop_front(); } Entity entity(entityId); entity.registry = this; this->entitiesToBeAdded.insert(entity); if (entityId >= this->entityComponentSignatures.size()) { this->entityComponentSignatures.resize(entityId + 1); } Logger::Info("Entity created with id = %d", entityId); return entity; } void Registry::killEntity(Entity entity) { Logger::Info("Entity #%d flagged for killing", entity.getId()); this->entitiesToBeKilled.insert(entity); } void Registry::addEntityToSystems(Entity entity) { const auto entityId = entity.getId(); const auto entityComponentSignature = this->entityComponentSignatures[entityId]; for(auto &system: this->systems) { const auto systemComponentSignature = system.second->getComponentSignature(); bool isInterested = (entityComponentSignature & systemComponentSignature) == systemComponentSignature; if (isInterested) { system.second->addEntity(entity); } } } void Registry::removeEntityFromSystems(Entity entity) { for (auto &system: this->systems) { system.second->removeEntity(entity); } } void Registry::update() { /* Add pending entities */ for(auto entity: this->entitiesToBeAdded) { this->addEntityToSystems(entity); } this->entitiesToBeAdded.clear(); for(auto entity: this->entitiesToBeKilled) { this->removeEntityFromSystems(entity); this->entityComponentSignatures[entity.getId()].reset(); for(auto pool: this->componentPools) { if (pool != nullptr) { pool->removeEntityFromPool(entity.getId()); } } this->freeIds.push_back(entity.getId()); this->removeEntityTag(entity); this->removeEntityGroup(entity); } this->entitiesToBeKilled.clear(); } void Registry::tagEntity(Entity entity, const std::string &tag) { this->entityPerTag.emplace(tag, entity); this->tagPerEntity.emplace(entity.getId(), tag); } bool Registry::entityHasTag(Entity entity, const std::string &tag) const { if (this->tagPerEntity.find(entity.getId()) == this->tagPerEntity.end()) { return false; } return this->entityPerTag.find(tag)->second == entity; } Entity Registry::getEntityByTag(const std::string &tag) const { return this->entityPerTag.at(tag); } void Registry::removeEntityTag(Entity entity) { auto taggedEntity = this->tagPerEntity.find(entity.getId()); if (taggedEntity != this->tagPerEntity.end()) { auto tag = taggedEntity->second; this->entityPerTag.erase(tag); this->tagPerEntity.erase(taggedEntity); } } void Registry::groupEntity(Entity entity, const std::string &groupName) { this->entitiesPerGroup.emplace(groupName, std::set()); this->entitiesPerGroup[groupName].emplace(entity); this->groupPerEntity.emplace(entity.getId(), groupName); } bool Registry::entityBelongsToGroup(Entity entity, const std::string &groupName) const { if (this->entitiesPerGroup.find(groupName) == this->entitiesPerGroup.end()) { return false; } auto groupEntities = this->entitiesPerGroup.at(groupName); return groupEntities.find(entity) != groupEntities.end(); } std::vector Registry::getEntitiesByGroup(const std::string &groupName) const { auto &setOfEntities = this->entitiesPerGroup.at(groupName); return std::vector(setOfEntities.begin(), setOfEntities.end()); } void Registry::removeEntityGroup(Entity entity) { auto groupedEntity = this->groupPerEntity.find(entity.getId()); if (groupedEntity != this->groupPerEntity.end()) { auto group = this->entitiesPerGroup.find(groupedEntity->second); if (group != this->entitiesPerGroup.end()) { auto entityInGroup = group->second.find(entity); if (entityInGroup != group->second.end()) { group->second.erase(entityInGroup); } } groupPerEntity.erase(groupedEntity); } }