FR 2797173:

* When hovering the cursor/cross-hair over a visible monster which has
  a blocked line of fire, describe the monster as having a blocked
  line of fire.

* If a player tracer beam is fired at a visble monster or square which has
  a blocked line of fire, warn the player about it and allow the player
  to cancel.


git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@9845 c06c8d41-db1a-0410-9941-cceddc491573

2 files changed, 51 insertions, 1 deletions

diff --git a/crawl-ref/source/beam.cc b/crawl-ref/source/beam.cc
index 5f86991643..78cd63f25e 100644
--- a/crawl-ref/source/beam.cc
+++ b/crawl-ref/source/beam.cc
@@ -1792,6 +1792,41 @@ void bolt::hit_wall()
     const dungeon_feature_type feat = grd(pos());
     ASSERT( grid_is_solid(feat) );
 
+    if (is_tracer && YOU_KILL(thrower) && flavour != BEAM_DIGGING
+        && flavour <= BEAM_LAST_REAL && pos() != target  && pos() != source
+        && !affects_nothing && bounces == 0 && reflections == 0
+        && see_grid(target) && !grid_is_solid(grd(target)))
+    {
+        // Okay, with all those tests passed, this is probably an instance
+        // of the player manually targetting something whose line of fire
+        // is blocked, even though its line of sight isn't blocked.  Give
+        // a warning about this fact.
+        std::string prompt = "Your line of fire to ";
+        const monsters* mon = monster_at(target);
+
+        if (mon && you.can_see(mon))
+            prompt += mon->name(DESC_NOCAP_THE);
+        else
+        {
+            prompt += "the targeted "
+                    + feature_description(target, false, DESC_PLAIN, false);
+        }
+
+        prompt += " is blocked by "
+                + feature_description(pos(), false, DESC_NOCAP_A, false);
+
+        prompt += ". Continue anyway?";
+
+        if (!yesno(prompt.c_str(), false, 'n'))
+        {
+            beam_cancelled = true;
+            finish_beam();
+            return;
+        }
+
+        // Well, we warned them.
+    }
+
     if (affects_wall(feat))
         affect_wall();
     else if (is_bouncy(feat) && !in_explosion_phase)
diff --git a/crawl-ref/source/directn.cc b/crawl-ref/source/directn.cc
index 5f6aa57fc9..7959b19807 100644
--- a/crawl-ref/source/directn.cc
+++ b/crawl-ref/source/directn.cc
@@ -958,7 +958,8 @@ bool _dist_ok(const dist& moves, int range, targ_mode_type mode,
     return (true);
 }
 
-static bool _blocked_ray(const coord_def &where)
+static bool _blocked_ray(const coord_def &where,
+                         dungeon_feature_type* feat = NULL)
 {
     ray_def ray;
     find_ray(you.pos(), where, true, ray, 0, true);
@@ -967,7 +968,11 @@ static bool _blocked_ray(const coord_def &where)
     while (ray.pos() != where)
     {
         if (grd(ray.pos()) <= DNGN_MINMOVE)
+        {
+            if (feat != NULL)
+                *feat = grd(ray.pos());
             return (true);
+        }
         ray.advance_through(where);
     }
     return (false);
@@ -3114,6 +3119,16 @@ static std::string _get_monster_desc(const monsters *mon)
     else if (mons_enslaved_soul(mon))
         text += pronoun + " is a disembodied soul.\n";
 
+    dungeon_feature_type blocking_feat;
+    if (_blocked_ray(mon->pos(), &blocking_feat))
+    {
+        text += "Your line of fire to " + lowercase_string(pronoun)
+              + " is blocked by "
+              + feature_description(blocking_feat, NUM_TRAPS, false,
+                                    DESC_NOCAP_A)
+              + "\n";
+    }
+
     text += _mon_enchantments_string(mon);
     return text;
 }