#define WORLD_MAX_ENTITIES 5000

enum {
	ENTITY_NONE,
	ENTITY_BALL
};

struct entity_ball {
	vec2 pos;
	vec2 vel;
};

union entity_union {
	struct entity_ball ball;
};

struct entity {
	int kind;
	union entity_union e;
};

struct world;

struct world *dp_world_create();
void dp_world_free(struct world *);

int dp_world_create_entity(struct world *, int kind);
struct entity *dp_world_find_entity(struct world *, int entity_id);
int dp_world_remove_entity(struct world *, int entity_id);

int dp_world_tick(struct world *, double delta);