#define COLLIDES(sprite) ((sprite)->flags & COLLIDE)
-Sprite *free_sprites[N_TYPES]; // lists of free sprites, by type.
+extern Sprite *free_sprites[N_TYPES]; // lists of free sprites, by type.
void do_collision(Sprite *a, Sprite *b);
void collisions(void);
uint32_t area;
// ROCK extras
int type;
+ int life;
};