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Refactor ecs::entity_container & add documentation

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This commit is contained in:
Nikita Lisitsa 2023-08-22 22:36:04 +03:00
parent c1991cbb57
commit 82682c0317
2 changed files with 116 additions and 79 deletions
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164
libs/ecs/include/psemek/ecs/entity_container.hpp
View file

@ -15,93 +15,37 @@ namespace psemek::ecs
struct entity_container
{
// Create an entity with the specified components
// NB: equivalent to create() followed by a
// series of attach() calls, but faster
template <typename ... Components>
entity_handle create(Components && ... components)
{
detail::component_uuid_holder<Components...> uuids;
detail::component_mask mask = component_index_.make_component_mask(uuids.get());
entity_handle create(Components && ... components);
auto insert_result = table_container_.insert<Components...>(mask, uuids.get());
auto table = insert_result.first;
bool created = insert_result.second;
// Check if an entity handle refers to an active entity
// UB if the handle wasn't obtained by a create() call
bool alive(entity_handle const & entity) const;
if (created)
{
query_cache_container_.apply([table](detail::query_cache & cache){
cache.add(table);
}, mask);
}
// Destroy an entity
// UB if the handle wasn't obtained by a create() call
// or if the entity was already destroyed
void destroy(entity_handle const & entity);
auto id = entity_list_.create(table, table->row_count());
entity_handle handle{id, entity_list_.get_entities()[id].epoch};
[[maybe_unused]] entity_accessor accessor = get(handle);
table->push_row(id);
((accessor.get<Components>() = std::move(components)), ...);
return handle;
}
bool alive(entity_handle const & entity) const
{
return entity_list_.get_entities()[entity.id].epoch == entity.epoch;
}
void destroy(entity_handle const & entity)
{
// Swap with the last row in that table
auto entities = entity_list_.get_entities();
auto & data = entities[entity.id];
auto table_entity_ids = data.table->get_entity_ids();
data.table->swap_rows(data.row, table_entity_ids.size() - 1);
data.table->pop_row();
auto swap_id = table_entity_ids[data.row];
auto & swap_data = entities[swap_id];
swap_data.row = data.row;
entity_list_.destroy(entity.id);
}
// Get an entity accessor for an entity
// UB if the handle wasn't obtained by a create() call
// or if the entity isn't active
entity_accessor get(entity_handle const & entity);
// Create a query cache that can be used for the
// apply() call to speed it up
template <typename ... Components>
query_cache cache()
{
detail::component_uuid_holder<Components...> uuids;
detail::component_mask mask = component_index_.make_component_mask(uuids.get());
auto result = query_cache_container_.create(mask, uuids.get());
table_container_.apply([&](detail::table & table){
result->add(&table);
}, mask);
return result;
}
query_cache cache();
// Apply a function to all entities having the specified
// components. The function signature is void(entity_handle, components...)
// An optional query cache can be supplied to speed up the call
// UB if the cache wasn't created with the exact same component sequence
template <typename ... Components, typename Function>
void apply(Function && function, query_cache cache = {})
{
if (!cache)
cache = this->cache<Components...>();
for (auto const & entry : cache->tables)
{
detail::static_apply_helper<Components...> apply_helper(entry.table->get_entity_ids(), entity_list_.get_entities());
for (std::size_t i = 0; i < sizeof...(Components); ++i)
apply_helper.pointers[i] = entry.table->get_component_pointers()[entry.column_ids[i]];
for (std::size_t i = 0; i < apply_helper.size(); ++i)
{
apply_helper.apply(function);
apply_helper.advance();
}
}
}
entity_accessor get(entity_handle const & entity)
{
auto const & data = entity_list_.get_entities()[entity.id];
return {data.table, data.row};
}
void apply(Function && function, query_cache cache = {});
private:
detail::entity_list entity_list_;
@ -110,4 +54,66 @@ namespace psemek::ecs
detail::query_cache_container query_cache_container_;
};
template <typename ... Components>
entity_handle entity_container::create(Components && ... components)
{
detail::component_uuid_holder<Components...> uuids;
detail::component_mask mask = component_index_.make_component_mask(uuids.get());
auto insert_result = table_container_.insert<Components...>(mask, uuids.get());
auto table = insert_result.first;
bool created = insert_result.second;
if (created)
{
query_cache_container_.apply([table](detail::query_cache & cache){
cache.add(table);
}, mask);
}
auto id = entity_list_.create(table, table->row_count());
entity_handle handle{id, entity_list_.get_entities()[id].epoch};
[[maybe_unused]] entity_accessor accessor = get(handle);
table->push_row(id);
((accessor.get<Components>() = std::move(components)), ...);
return handle;
}
template <typename ... Components>
query_cache entity_container::cache()
{
detail::component_uuid_holder<Components...> uuids;
detail::component_mask mask = component_index_.make_component_mask(uuids.get());
auto result = query_cache_container_.create(mask, uuids.get());
table_container_.apply([&](detail::table & table){
result->add(&table);
}, mask);
return result;
}
template <typename ... Components, typename Function>
void entity_container::apply(Function && function, query_cache cache)
{
if (!cache)
cache = this->cache<Components...>();
for (auto const & entry : cache->tables)
{
detail::static_apply_helper<Components...> apply_helper(entry.table->get_entity_ids(), entity_list_.get_entities());
for (std::size_t i = 0; i < sizeof...(Components); ++i)
apply_helper.pointers[i] = entry.table->get_component_pointers()[entry.column_ids[i]];
for (std::size_t i = 0; i < apply_helper.size(); ++i)
{
apply_helper.apply(function);
apply_helper.advance();
}
}
}
}

31
libs/ecs/source/entity_container.cpp Normal file
View file

@ -0,0 +1,31 @@
#include <psemek/ecs/entity_container.hpp>
namespace psemek::ecs
{
bool entity_container::alive(entity_handle const & entity) const
{
return entity_list_.get_entities()[entity.id].epoch == entity.epoch;
}
void entity_container::destroy(entity_handle const & entity)
{
// Swap with the last row in that table
auto entities = entity_list_.get_entities();
auto & data = entities[entity.id];
auto table_entity_ids = data.table->get_entity_ids();
data.table->swap_rows(data.row, table_entity_ids.size() - 1);
data.table->pop_row();
auto swap_id = table_entity_ids[data.row];
auto & swap_data = entities[swap_id];
swap_data.row = data.row;
entity_list_.destroy(entity.id);
}
entity_accessor entity_container::get(entity_handle const & entity)
{
auto const & data = entity_list_.get_entities()[entity.id];
return {data.table, data.row};
}
}