/**
* @brief Gets the distance from the Vec2.
*
* @usage my_vec:dist() -- Gets length of the vector (distance from origin).
* @usage my_vec:dist( your_vec ) -- Gets distance from both vectors (your_vec - my_vec).
*
* @luaparam v Vector to act as origin.
* @luaparam v2 Vector to get distance from, uses origin (0,0) if not set.
* @luareturn The distance calculated.
* @luafunc dist( v, v2 )
*/
static int vectorL_distance( lua_State *L )
{
LuaVector *v1, *v2;
double dist;
/* Get self. */
v1 = luaL_checkvector(L,1);
/* Get rest of parameters. */
v2 = NULL;
if (lua_gettop(L) > 1) {
v2 = luaL_checkvector(L,2);
}
/* Get distance. */
if (v2 == NULL)
dist = vect_odist(&v1->vec);
else
dist = vect_dist(&v1->vec, &v2->vec);
/* Return the distance. */
lua_pushnumber(L, dist);
return 1;
}
/**
* @brief The AI of seeker missiles.
*
* @param w Weapon to do the thinking.
* @param dt Current delta tick.
*/
static void think_seeker( Weapon* w, const double dt )
{
double diff;
double vel;
Pilot *p;
int effect;
Vector2d v;
double t;
if (w->target == w->parent) return; /* no self shooting */
p = pilot_get(w->target); /* no null pilot_nstack */
if (p==NULL) {
weapon_setThrust( w, 0. );
weapon_setTurn( w, 0. );
return;
}
/* Handle by status. */
switch (w->status) {
case WEAPON_STATUS_OK:
if (w->lockon < 0.)
w->status = WEAPON_STATUS_LOCKEDON;
break;
case WEAPON_STATUS_LOCKEDON: /* Check to see if can get jammed */
if ((p->jam_range != 0.) && /* Target has jammer and weapon is in range */
(vect_dist(&w->solid->pos,&p->solid->pos) < p->jam_range)) {
/* Check to see if weapon gets jammed */
if (RNGF() < p->jam_chance - w->outfit->u.amm.resist) {
w->status = WEAPON_STATUS_JAMMED;
/* Give it a nice random effect */
effect = RNG(0,3);
switch (effect) {
case 0: /* Stuck in left loop */
weapon_setTurn( w, w->outfit->u.amm.turn );
break;
case 1: /* Stuck in right loop */
weapon_setTurn( w, -w->outfit->u.amm.turn );
break;
default: /* Blow up. */
w->timer = -1.;
break;
}
}
else /* Can't get jammed anymore */
w->status = WEAPON_STATUS_UNJAMMED;
}
/* Purpose fallthrough */
case WEAPON_STATUS_UNJAMMED: /* Work as expected */
/* Smart seekers take into account ship velocity. */
if (w->outfit->u.amm.ai == 2) {
/* Calculate time to reach target. */
vect_cset( &v, p->solid->pos.x - w->solid->pos.x,
p->solid->pos.y - w->solid->pos.y );
t = vect_odist( &v ) / w->outfit->u.amm.speed;
/* Calculate target's movement. */
vect_cset( &v, v.x + t*(p->solid->vel.x - w->solid->vel.x),
v.y + t*(p->solid->vel.y - w->solid->vel.y) );
/* Get the angle now. */
diff = angle_diff(w->solid->dir, VANGLE(v) );
}
/* Other seekers are stupid. */
else {
diff = angle_diff(w->solid->dir, /* Get angle to target pos */
vect_angle(&w->solid->pos, &p->solid->pos));
}
/* Set turn. */
weapon_setTurn( w, CLAMP( -w->outfit->u.amm.turn, w->outfit->u.amm.turn,
10 * diff * w->outfit->u.amm.turn ));
break;
case WEAPON_STATUS_JAMMED: /* Continue doing whatever */
/* Do nothing, dir_vel should be set already if needed */
break;
default:
WARN("Unknown weapon status for '%s'", w->outfit->name);
break;
}
/* Limit speed here */
vel = MIN(w->outfit->u.amm.speed, VMOD(w->solid->vel) + w->outfit->u.amm.thrust*dt);
vect_pset( &w->solid->vel, vel, w->solid->dir );
/*limit_speed( &w->solid->vel, w->outfit->u.amm.speed, dt );*/
}
