beam.cc: seeing clouds polymorphed

Seeing a cloud changed by a polymorph beam will give a message (with a
different message for one you're standing in), and will also make the
effect of the beam obvious.

1 files changed, 22 insertions, 1 deletions

diff --git a/crawl-ref/source/beam.cc b/crawl-ref/source/beam.cc
index 2942a600d8..8a10cc4531 100644
--- a/crawl-ref/source/beam.cc
+++ b/crawl-ref/source/beam.cc
@@ -3174,7 +3174,28 @@ void bolt::affect_place_clouds()
         cloud_type& ctype = env.cloud[cloudidx].type;
         // Polymorph randomly changes clouds in its path
         if (flavour == BEAM_POLYMORPH)
-            ctype = static_cast<cloud_type>(1 + random2(8));
+        {
+            cloud_type new_type = static_cast<cloud_type>(1 + random2(8));
+
+            if (new_type == ctype)
+                return;
+
+            if (p == you.pos())
+            {
+                mprf("The %s you are in turns into %s!",
+                     cloud_name(ctype).c_str(), cloud_name(new_type).c_str());
+                obvious_effect = true;
+            }
+            else if (you.see_cell(p))
+            {
+                mprf("A cloud of %s turns into %s.",
+                     cloud_name(ctype).c_str(), cloud_name(new_type).c_str());
+                obvious_effect = true;
+            }
+
+            ctype = new_type;
+            return;
+        }
 
         // fire cancelling cold & vice versa
         if ((ctype == CLOUD_COLD