120 lines
6.7 KiB
C
120 lines
6.7 KiB
C
// haloopdy - 2024
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// A super simple, all macro-driven ecs implementation.
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// Macros create a struct and associated functions to build
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// a simple, lightweight ecs implementation
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#ifndef __HALOO3D_ECS2_H
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#define __HALOO3D_ECS2_H
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#include <stdint.h>
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#ifndef ECS_MAXENTITIES
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#define ECS_MAXENTITIES 1024
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#endif
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#define ECS_MAXCTYPES 63 // uint64 bits minus one
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typedef uint64_t ecs_cid;
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typedef int ecs_eid;
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#define ECS_START(name) \
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typedef struct { \
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ecs_cid entities[ECS_MAXENTITIES]; \
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ecs_eid entitytop;
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#define ECS_END(name) \
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} \
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name; \
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static void name##_init(name *_ecs) { memset(_ecs, 0, sizeof(name)); } \
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static ecs_eid name##_newentity(name *_ecs, ecs_cid basecomponents) { \
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for (int i = 0; i < ECS_MAXENTITIES; i++) { \
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ecs_eid id = _ecs->entitytop++; \
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if (_ecs->entities[id] == 0) { \
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_ecs->entities[id] = (1ULL << ECS_MAXCTYPES) | basecomponents; \
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return id; \
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} \
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} \
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return -1; \
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} \
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static void name##_deleteentity(name *_ecs, ecs_eid eid) { \
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if (eid >= 0 && eid < ECS_MAXENTITIES) \
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_ecs->entities[eid] = 0; \
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} \
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static int name##_match(name *_ecs, ecs_eid _eid, ecs_cid _comps) { \
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ecs_cid _realcomps = (1ULL << ECS_MAXCTYPES) | _comps; \
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return (_ecs->entities[_eid] & _realcomps) == _realcomps; \
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}
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#define ECS_COMPONENT(type) type c_##type[ECS_MAXENTITIES];
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#define ECS_CID(type, id) \
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const int type##_id = id; \
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const ecs_cid type##_fl = (1ULL << id);
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// Set the given entity to have the given component (by type). Follow this
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// macro immediately with the struct initializer
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#define ECS_SETCOMPONENT(_ecs, eid, type) \
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(_ecs)->entities[eid] |= type##_fl; \
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(_ecs)->c_##type[eid] = (type)
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// Add a system function which automatically calls your given function with
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// pre-pulled items from the entity component arrays. The new function is
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// named the same as the old one, just with _run appeneded
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#define ECS_SYSTEM1(ecsname, fname, type1) \
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void fname##_run(ecsname *_ecs, ecs_eid eid) { \
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ecs_cid _ecsflags = type1##_fl; \
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if (ecsname##_match(_ecs, eid, _ecsflags)) { \
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fname(_ecs->c_##type1 + eid); \
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} \
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}
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// Add a system function which automatically calls your given function with
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// pre-pulled items from the entity component arrays. The new function is
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// named the same as the old one, just with _run appeneded
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#define ECS_SYSTEM2(ecsname, fname, type1, type2) \
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void fname##_run(ecsname *_ecs, ecs_eid eid) { \
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ecs_cid _ecsflags = type1##_fl | type2##_fl; \
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if (ecsname##_match(_ecs, eid, _ecsflags)) { \
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fname(_ecs->c_##type1 + eid, _ecs->c_##type2 + eid); \
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} \
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}
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// Add a system function which automatically calls your given function with
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// pre-pulled items from the entity component arrays. The new function is
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// named the same as the old one, just with _run appeneded
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#define ECS_SYSTEM3(ecsname, fname, type1, type2, type3) \
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void fname##_run(ecsname *_ecs, ecs_eid eid) { \
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ecs_cid _ecsflags = type1##_fl | type2##_fl | type3##_fl; \
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if (ecsname##_match(_ecs, eid, _ecsflags)) { \
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fname(_ecs->c_##type1 + eid, _ecs->c_##type2 + eid, \
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_ecs->c_##type3 + eid); \
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} \
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}
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// Add a system function which automatically calls your given function with
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// pre-pulled items from the entity component arrays. The new function is
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// named the same as the old one, just with _run appeneded
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#define ECS_SYSTEM4(ecsname, fname, type1, type2, type3, type4) \
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void fname##_run(ecsname *_ecs, ecs_eid eid) { \
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ecs_cid _ecsflags = type1##_fl | type2##_fl | type3##_fl | type4##_fl; \
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if (ecsname##_match(_ecs, eid, _ecsflags)) { \
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fname(_ecs->c_##type1 + eid, _ecs->c_##type2 + eid, \
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_ecs->c_##type3 + eid, _ecs->c_##type4 + eid); \
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} \
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}
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// Add a system function which automatically calls your given function with
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// pre-pulled items from the entity component arrays. The new function is
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// named the same as the old one, just with _run appeneded
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#define ECS_SYSTEM5(ecsname, fname, type1, type2, type3, type4, type5) \
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void fname##_run(ecsname *_ecs, ecs_eid eid) { \
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ecs_cid _ecsflags = \
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type1##_fl | type2##_fl | type3##_fl | type4##_fl | type5##_fl; \
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if (ecsname##_match(_ecs, eid, _ecsflags)) { \
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fname(_ecs->c_##type1 + eid, _ecs->c_##type2 + eid, \
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_ecs->c_##type3 + eid, _ecs->c_##type4 + eid, \
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_ecs->c_##type5 + eid); \
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} \
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}
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#endif
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