quakeforge/include/QF/ecs/entity.h
Bill Currie 6701f921a4 [ecs] Add a function to safely get a component
It returns null if the entity is invalid or doesn't have the component.
Useful when the component is optional.
2023-07-04 16:48:15 +09:00

142 lines
3.7 KiB
C

/*
entity.h
ECS entity management
Copyright (C) 2022 Bill Currie <bill@taniwha.org>
Author: Bill Currie <bill@taniwha.org>
Date: 2022/10/07
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifndef __QF_ecs_entity_h
#define __QF_ecs_entity_h
/** \defgroup ecs_entity Entity Component System Entities
\ingroup ecs
*/
///@{
#define ENT_IDBITS 20
#define nullent (~0u)
#define ENTINLINE GNU89INLINE inline
ENTINLINE int ECS_EntValid (uint32_t id, ecs_registry_t *reg);
ENTINLINE uint32_t Ent_Index (uint32_t id);
ENTINLINE uint32_t Ent_Generation (uint32_t id);
ENTINLINE uint32_t Ent_NextGen (uint32_t id);
ENTINLINE int Ent_HasComponent (uint32_t ent, uint32_t comp,
ecs_registry_t *reg);
ENTINLINE void *Ent_GetComponent (uint32_t ent, uint32_t comp,
ecs_registry_t *reg);
ENTINLINE void *Ent_SafeGetComponent (uint32_t ent, uint32_t comp,
ecs_registry_t *reg);
ENTINLINE void *Ent_SetComponent (uint32_t ent, uint32_t comp,
ecs_registry_t *registry, const void *data);
#undef ENTINLINE
#ifndef IMPLEMENT_ECS_ENTITY_Funcs
#define ENTINLINE GNU89INLINE inline
#else
#define ENTINLINE VISIBLE
#endif
ENTINLINE uint32_t
Ent_Index (uint32_t id)
{
return id & ((1 << ENT_IDBITS) - 1);
}
ENTINLINE uint32_t
Ent_Generation (uint32_t id)
{
return id & ~((1 << ENT_IDBITS) - 1);
}
ENTINLINE uint32_t
Ent_NextGen(uint32_t id)
{
return id + (1 << ENT_IDBITS);
}
ENTINLINE int
ECS_EntValid (uint32_t id, ecs_registry_t *reg)
{
uint32_t ind = Ent_Index (id);
return ind < reg->num_entities && reg->entities[ind] == id;
}
ENTINLINE int
Ent_HasComponent (uint32_t ent, uint32_t comp, ecs_registry_t *reg)
{
ecs_pool_t *pool = &reg->comp_pools[comp];
uint32_t ind = pool->sparse[Ent_Index (ent)];
return ind < pool->count && pool->dense[ind] == ent;
}
ENTINLINE void *
Ent_GetComponent (uint32_t ent, uint32_t comp, ecs_registry_t *reg)
{
const component_t *component = &reg->components.a[comp];
uint32_t ind = reg->comp_pools[comp].sparse[Ent_Index (ent)];
byte *data = reg->comp_pools[comp].data;
return data + ind * component->size;
}
ENTINLINE void *
Ent_SafeGetComponent (uint32_t ent, uint32_t comp, ecs_registry_t *reg)
{
if (!ECS_EntValid (ent, reg) || !Ent_HasComponent (ent, comp, reg)) {
return 0;
}
const component_t *component = &reg->components.a[comp];
uint32_t ind = reg->comp_pools[comp].sparse[Ent_Index (ent)];
byte *data = reg->comp_pools[comp].data;
return data + ind * component->size;
}
void *Ent_AddComponent (uint32_t ent, uint32_t comp, ecs_registry_t *registry);
void Ent_RemoveComponent (uint32_t ent, uint32_t comp,
ecs_registry_t *registry);
ENTINLINE void *
Ent_SetComponent (uint32_t ent, uint32_t comp, ecs_registry_t *registry,
const void *data)
{
void *dst = Ent_AddComponent (ent, comp, registry);
if (data) {
return Component_CopyElements (&registry->components.a[comp],
dst, 0, data, 0, 1);
} else {
return Component_CreateElements (&registry->components.a[comp],
dst, 0, 1);
}
}
#undef ENTINLINE
///@}
#endif//__QF_ecs_entity_h