Tornado: alter the rules for "short translocation".

You cannot move a tornado to a place where it did not reach yet.

Outside of that range, check if a new tornado can possibly intersect with
the area the old one reached, and impose a cooldown if yes.

Also, clear the cooldown if you went farther away.

1 files changed, 53 insertions, 16 deletions

diff --git a/crawl-ref/source/spl-tornado.cc b/crawl-ref/source/spl-tornado.cc
index 825b8081d4..e3bc6e3a7b 100644
--- a/crawl-ref/source/spl-tornado.cc
+++ b/crawl-ref/source/spl-tornado.cc
@@ -194,6 +194,23 @@ static int _rdam(int rage)
         return rage * 10 - 50;
 }
 
+static int _tornado_age(const actor *caster)
+{
+    if (caster->props.exists("tornado_since"))
+        return you.elapsed_time - caster->props["tornado_since"].get_int();
+    return 100; // for permanent tornadoes
+}
+
+// time needed to reach the given radius
+static int _age_needed(int r)
+{
+    if (r <= 0)
+        return 0;
+    if (r > TORNADO_RADIUS)
+        return INT_MAX;
+    return sqr(r) * 5 / 4;
+}
+
 void tornado_damage(actor *caster, int dur)
 {
     if (!dur)
@@ -210,9 +227,7 @@ void tornado_damage(actor *caster, int dur)
     noisy(25, org, caster->mindex());
     WindSystem winds(org);
 
-    int age = 100; // for permanent tornadoes
-    if (caster->props.exists("tornado_since"))
-        age = you.elapsed_time - caster->props["tornado_since"].get_int();
+    int age = _tornado_age(caster);
     ASSERT(age >= 0);
 
     std::vector<actor*>        move_act;   // victims to move
@@ -234,7 +249,7 @@ void tornado_damage(actor *caster, int dur)
             ++count_i;
         }
         // effective age at radius r
-        int rage = age - sqr(r) * 5 / 4;
+        int rage = age - _age_needed(r);
         /* Not just "portion of time affected":
                           **
                         **
@@ -447,21 +462,43 @@ void cancel_tornado(bool tloc)
 
 void tornado_move(const coord_def &p)
 {
-    if (!you.duration[DUR_TORNADO])
+    if (!you.duration[DUR_TORNADO] && !you.duration[DUR_TORNADO_COOLDOWN])
         return;
 
+    int age = _tornado_age(&you);
     int dist2 = (you.pos() - p).abs();
-    if (dist2 > sqr(TORNADO_RADIUS) + 1)
-        cancel_tornado(true);
-    else if (dist2 > 2)
+    if (dist2 <= 2)
+        return;
+
+    int dist = 0;
+    while (dist * dist + 1 < dist2)
+        dist++;
+
+    if (!you.duration[DUR_TORNADO])
     {
-        int dist = 0;
-        while (dist * dist + 1 < dist2)
-            dist++;
-        dist--;
-        if (dist > 0)
-            dprf("Tloc penalty: reducing tornado by %d turns", dist);
-        you.duration[DUR_TORNADO] = std::max(1,
-                     you.duration[DUR_TORNADO] - dist * 10);
+        if (age < _age_needed(dist - TORNADO_RADIUS))
+            you.duration[DUR_TORNADO_COOLDOWN] = 0;
+        return;
     }
+
+    if (age > _age_needed(dist))
+    {
+        // check for actual wind too, not just the radius
+        WindSystem winds(you.pos());
+        if (winds.has_wind(p))
+        {
+            // blinking/cTele inside an already windy area
+            dprf("Tloc penalty: reducing tornado by %d turns", dist - 1);
+            you.duration[DUR_TORNADO] = std::max(1,
+                         you.duration[DUR_TORNADO] - (dist - 1) * 10);
+            return;
+        }
+    }
+
+    cancel_tornado(true);
+
+    // there's an intersection between the area of the old tornado, and what
+    // a new one could possibly grow into
+    if (age > _age_needed(dist - TORNADO_RADIUS))
+        you.duration[DUR_TORNADO_COOLDOWN] = random_range(25, 35);
 }