4 files changed, 15 insertions, 2 deletions
diff --git a/crawl-ref/source/cloud.cc b/crawl-ref/source/cloud.cc
index 43fc2ee1c6..8ecfa7b158 100644
--- a/crawl-ref/source/cloud.cc
+++ b/crawl-ref/source/cloud.cc
@@ -264,3 +264,12 @@ void place_cloud(int cl_type, int ctarget_x,
         }
     }
 }                               // end place_cloud();
+
+bool is_opaque_cloud(unsigned char cloud_idx)
+{
+    if ( cloud_idx == EMPTY_CLOUD )
+        return false;
+    const int ctype = env.cloud[cloud_idx].type;
+    return ( ctype == CLOUD_BLACK_SMOKE ||
+             (ctype >= CLOUD_GREY_SMOKE && ctype <= CLOUD_STEAM) );
+}
diff --git a/crawl-ref/source/cloud.h b/crawl-ref/source/cloud.h
index 65cb2db888..94b25834c6 100644
--- a/crawl-ref/source/cloud.h
+++ b/crawl-ref/source/cloud.h
@@ -24,4 +24,6 @@ void place_cloud(int cl_type, int ctarget_x, int ctarget_y, int cl_range,
 
 void manage_clouds(void);
 
+bool is_opaque_cloud(unsigned char cloud_idx);
+
 #endif
diff --git a/crawl-ref/source/enum.h b/crawl-ref/source/enum.h
index 65112200c4..47863dcb21 100644
--- a/crawl-ref/source/enum.h
+++ b/crawl-ref/source/enum.h
@@ -533,7 +533,7 @@ enum cloud_type
     CLOUD_MIASMA,
     CLOUD_BLACK_SMOKE,
     CLOUD_MIST,
-    CLOUD_RANDOM = 98, 
+    CLOUD_RANDOM = 98,
     CLOUD_DEBUGGING = 99    //   99: used once as 'nonexistent cloud' {dlb}
 };
 
diff --git a/crawl-ref/source/view.cc b/crawl-ref/source/view.cc
index 5f855bb9da..5a8ec55e06 100644
--- a/crawl-ref/source/view.cc
+++ b/crawl-ref/source/view.cc
@@ -35,6 +35,7 @@
 #include "externs.h"
 
 #include "command.h"
+#include "cloud.h"
 #include "clua.h"
 #include "debug.h"
 #include "delay.h"
@@ -1667,7 +1668,8 @@ void losight(FixedArray < unsigned int, 19, 19 > &sh,
                     continue;
 
                 // if this cell is opaque...
-                if ( grid_is_opaque(gr[realx][realy]))
+                if ( grid_is_opaque(gr[realx][realy]) ||
+                     is_opaque_cloud(env.cgrid[realx][realy]) )
                 {
                     // then block the appropriate rays
                     for ( unsigned int i = 0; i < num_words; ++i )