#define     MAX_PNTLIST_VERTICES    16

typedef struct {
    float   x;
    float   y;
} vec_2d;

typedef struct {

    vec_2d  pos;                                // position
    vec_2d  vel;                                // velocity
    vec_2d  acc;                                // acceleration

    vec_2d  com;                                // center of mass

    vec_2d  pnt_list[MAX_PNTLIST_VERTICES;      // point list
    int     pnt_list_num;                       // number of points

    int     rot;                                // rotation

} obj_polygon;