Created
December 2, 2023 16:14
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flecs - C lifeclcye hooks example
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#include <flecs.h> | |
#include <stdio.h> | |
typedef struct Data { | |
int x; | |
} Data; | |
typedef struct Test { | |
Data* ptr; | |
} Test; | |
ECS_COMPONENT_DECLARE(Test); | |
ECS_CTOR(Test, ptr, { | |
ptr->ptr = ecs_os_malloc(sizeof(Data)); | |
ptr->ptr->x = 0; // Default value | |
printf("ctor: %d\n", ptr->ptr->x); | |
}) | |
ECS_DTOR(Test, ptr, { | |
printf("dtor: %d\n", ptr->ptr->x); | |
ecs_os_free(ptr->ptr); | |
}) | |
ECS_MOVE(Test, dst, src, { | |
printf("move: %d->%d\n", src->ptr->x, dst->ptr->x); | |
dst->ptr = src->ptr; | |
// Clear the pointer in src since it's been moved tp dst and we | |
// don't want to free it when `src` ges destroyed | |
src->ptr = NULL; | |
}) | |
void testRemoved(ecs_iter_t *it) { | |
Test *test = ecs_field(it, Test, 1); | |
for (int i = 0; i < it->count; i++) { | |
printf("on_remove: %d\n", test[i].ptr->x); | |
} | |
} | |
void testSet(ecs_iter_t *it) { | |
Test *test = ecs_field(it, Test, 1); | |
for (int i = 0; i < it->count; i++) { | |
printf("on_set: %d\n", test[i].ptr->x); | |
} | |
} | |
void ecs_copy_illegal(void *dst, const void *src, int32_t c, const ecs_type_info_t *ti) { | |
ecs_abort(ECS_INVALID_OPERATION, "invalid copy assignment for %s", ti->name); | |
} | |
int main(int argc, char *argv[]) { | |
ecs_world_t *ecs = ecs_init(); | |
ECS_COMPONENT_DEFINE(ecs, Test); | |
ecs_set_hooks(ecs, Test, { | |
.ctor = ecs_ctor(Test), | |
.dtor = ecs_dtor(Test), | |
.move = ecs_move(Test), | |
.copy = ecs_copy_illegal, // Prevent Test from being copied so that they never share the same pointer | |
.on_remove = testRemoved, | |
.on_set = testSet | |
}); | |
ecs_entity_t entity = ecs_new_id(ecs); | |
Test* test = ecs_emplace(ecs, entity, Test); // Emplace the component, this doesn't call the ctor allowing us to initialize the data in the table directly | |
Data* ptr = ecs_os_malloc(sizeof(Data)); | |
ptr->x = 1; | |
test->ptr = ptr; | |
ecs_modified(ecs, entity, Test); // Tell the ECS that we are done with modifying the component | |
// Modify the data in the component without doing any copy/move | |
test = ecs_get_mut(ecs, entity, Test); | |
test->ptr->x = 2; | |
ecs_modified(ecs, entity, Test); | |
ecs_remove(ecs, entity, Test); // testRemoved called for {2} | |
// Since the component was previously removed this will call the constructor to initialize the | |
// default value in the table, and then return that. | |
test = ecs_get_mut(ecs, entity, Test); | |
test->ptr->x = 3; | |
ecs_modified(ecs, entity, Test); | |
ecs_defer_begin(ecs); | |
ecs_remove(ecs, entity, Test); | |
test = ecs_get_mut(ecs, entity, Test); | |
test->ptr->x = 4; | |
ecs_modified(ecs, entity, Test); | |
ecs_defer_end(ecs); | |
ecs_fini(ecs); // testRemoved called for {4} | |
} |
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