[Freeciv-Dev] Re: (PR#4701) autoattack oddities esp. with cruise missiles

["Andy Smith" <andy@xxxxxxxxxxxxxx>]

On Sun, Jul 27, 2003 at 12:17:38PM -0700, Per I. Mathisen wrote:
> > So I suggest:
> >
> > 1. auto-attack should make sure that your own unit can engage the enemy
> >  unit at all, as a big fix.
> >
> > 2. As a game option, auto-attack should only operate on enemy units
> >  that can currently be seen by the player.  I say as an option
> >  because I can see how this greatly reduces the power of
> >  auto-attack and maybe some people desire the previous behaviour?
> 
> No, this should not be an option. Auto-attack that attacks units the
> player cannot see is clearly a bug.

[...]

> Yes, please write patches for these bugs.

How's this?  Appears to work:

4: doing autoattack for Cruise Missile (25/27) in Cirith Ungol, range 36(36), 
city_options 15
4: found enemy unit/stack at 13,20
4: defender is Destroyer
4: can't see Destroyer at (13,20)
4: found enemy unit/stack at 27,26
4: defender is Fighter
4: Cruise Missile at (25,27) cannot attack Fighter at (27,26)
4: found enemy unit/stack at 31,26
4: defender is Helicopter
4: chosen target=Helicopter [10/3/6] (31/26)

> If you look hard, I am sure you can find plenty more bugs in this
> code. It has always been pretty bad, and nobody has fixed or
> cleaned up this code in several years.

Will do.


--- freeciv-cvs/server/autoattack.c     2003-07-17 19:56:51.000000000 +0100
+++ freeciv-patched/server/autoattack.c 2003-07-29 07:00:37.000000000 +0100
@@ -44,6 +44,7 @@
 #include "unit.h"
 
 #include "gotohand.h"
+#include "maphand.h"
 #include "plrhand.h"
 #include "srv_main.h"
 #include "unithand.h"
@@ -111,6 +112,39 @@
     }
 
     /*
+     * Make sure the player can see both the location and the unit at that
+     * location, before allowing an auto-attack.  Without this, units attack
+     * into locations they cannot see, and maybe submarines are made
+     * erroneously visible too.
+     */
+    if (!map_get_known_and_seen(x, y, pplayer)
+       || !player_can_see_unit_at_location(pplayer, enemy, x, y)) {
+      freelog(LOG_DEBUG, "can't see %s at (%d,%d)", unit_name(enemy->type),
+             x, y);
+      continue;
+    }
+
+    /*
+     * is this the correct function to use here?  c_u_a_u_a_t() seems to assume
+     * that attacker is in an adjacent tile but I do not think it matters.
+     *
+     * On the other hand, we already checked everything that this function
+     * checks, except for missiles trying to attack air units, so perhaps we
+     * should just do that check here?  But doing a final sanity check to make
+     * sure our attacker can engage the enemy at all seems safest.
+     *
+     * Without this check, missiles are made useless for auto-attack as they
+     * get triggered by fighters and bombers and end up being wasted when they
+     * cannot engage.
+     */
+    if (!can_unit_attack_unit_at_tile(punit, enemy, x, y)) {
+      freelog(LOG_DEBUG, "%s at (%d,%d) cannot attack %s at (%d,%d)",
+             unit_name(punit->type), punit->x, punit->y,
+             unit_name(enemy->type), x, y);
+      continue;
+    }
+
+    /*
      *  perhaps there is a better algorithm in the ai-package -- fisch
      */
     score = (unit_type(enemy)->defense_strength + (enemy->hp / 2)