Files
PixelDefense/engine/libs/flecs/examples/c/entities/basics/src/main.c

62 lines
1.8 KiB
C

#include <basics.h>
#include <stdio.h>
typedef struct {
double x, y;
} Position;
int main(int argc, char *argv[]) {
ecs_world_t *ecs = ecs_init_w_args(argc, argv);
ECS_COMPONENT(ecs, Position);
ECS_TAG(ecs, Walking);
// Create an entity with name Bob
ecs_entity_t bob = ecs_set_name(ecs, 0, "Bob");
// The set operation finds or creates a component, and sets it.
ecs_set(ecs, bob, Position, {10, 20});
// The add operation adds a component without setting a value. This is
// useful for tags, or when adding a component with its default value.
ecs_add(ecs, bob, Walking);
// Get the value for the Position component
const Position *ptr = ecs_get(ecs, bob, Position);
printf("{%f, %f}\n", ptr->x, ptr->y);
// Overwrite the value of the Position component
ecs_set(ecs, bob, Position, {20, 30});
// Create another named entity
ecs_entity_t alice = ecs_set_name(ecs, 0, "Alice");
ecs_set(ecs, alice, Position, {10, 20});
ecs_add(ecs, alice, Walking);
// Print all the components the entity has. This will output:
// Position, Walking, (Identifier,Name)
char *str = ecs_type_str(ecs, ecs_get_type(ecs, alice));
printf("[%s]\n", str);
ecs_os_free(str);
// Remove tag
ecs_remove(ecs, alice, Walking);
// Iterate all entities with Position
ecs_iter_t it = ecs_term_iter(ecs, &(ecs_term_t){ .id = ecs_id(Position) });
while (ecs_term_next(&it)) {
Position *p = ecs_field(&it, Position, 1);
for (int i = 0; i < it.count; i ++) {
printf("%s: {%f, %f}\n", ecs_get_name(ecs, it.entities[i]),
p[i].x, p[i].y);
}
}
return ecs_fini(ecs);
// Output
// {10.000000, 20.000000}
// [Position, Walking, (Identifier,Name)]
// Alice: {10.000000, 20.000000}
// Bob: {20.000000, 30.000000}
}