frost module: during winter, some oceans freeze over

res/e3a/ships.xml

@@ -22,6 +22,8 @@
     <coast terrain="plain"/>
     <coast terrain="swamp"/>
     <coast terrain="desert"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="1" maxsize="10" reqsize="1">
       <requirement type="log" quantity="1"/>
     </construction>
@@ -83,6 +85,8 @@
   <ship name="catamaran" range="7" storm="0.25" damage="1.00" cabins="22" cargo="10000" cptskill="7" minskill="1" sumskill="20" opensea="yes">
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="8" maxsize="30" reqsize="1">
       <requirement type="mallorn" quantity="1"/>
       <requirement type="money" quantity="100"/>
@@ -93,6 +97,8 @@
   <ship name="cog" range="4" storm="0.50" damage="1.00" cabins="50" cargo="200000" cptskill="4" minskill="1" sumskill="20" opensea="yes">
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="4" maxsize="100" reqsize="1">
       <requirement type="log" quantity="1"/>
     </construction>
@@ -101,6 +107,8 @@
   <ship name="caravel" range="4" storm="0.50" damage="1.00" cabins="150" cargo="600000" cptskill="6" minskill="1" sumskill="30" opensea="yes">
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="6" maxsize="300" reqsize="1">
       <requirement type="log" quantity="1"/>
     </construction>
@@ -111,6 +119,8 @@
     <modifier type="defense" value="+2"/>
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="5" maxsize="100" reqsize="1">
       <requirement type="log" quantity="1"/>
       <requirement type="money" quantity="10"/>
@@ -121,6 +131,8 @@
     <modifier type="defense" value="+2"/>
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="7" maxsize="300" reqsize="1">
       <requirement type="log" quantity="1"/>
       <requirement type="money" quantity="10"/>
@@ -133,6 +145,8 @@
     <modifier type="tactics" factor="2.00"/>
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="5" maxsize="100" reqsize="1">
       <requirement type="log" quantity="1"/>
       <requirement type="money" quantity="10"/>
@@ -144,6 +158,8 @@
     <modifier type="tactics" factor="2.00"/>
     <coast terrain="ocean"/>
     <coast terrain="plain"/>
+    <coast terrain="iceberg_sleep"/>
+    <coast terrain="iceberg"/>
     <construction skill="shipcraft" minskill="7" maxsize="300" reqsize="1">
       <requirement type="log" quantity="1"/>
       <requirement type="money" quantity="10"/>

scripts/e3a/frost.lua

@@ -0,0 +1,36 @@
+module('frost', package.seeall)
+
+local function is_winter(turn)
+    local season = get_season(turn)
+    return season == "calendar::winter"
+end
+
+local function freeze(r)
+    for i, rn in ipairs(r.adj) do
+        -- each region has a chance to freeze
+        if rn.terrain=="ocean" and math.mod(rng_int(), 100)<20 then
+            rn.terrain = "iceberg_sleep"
+        end
+    end
+end
+
+local function thaw(r)
+    r.terrain = "ocean"
+end
+
+function update()
+    local turn = get_turn()
+    if is_winter(turn) then
+        for r in regions() do
+            if r.terrain=="glacier" then
+                freeze(r)
+            end
+        end
+    else if is_winter(turn-1) then
+        for r in regions() do
+            if r.terrain=="iceberg_sleep" then
+                thaw(r)
+            end
+        end
+    end
+end

scripts/eressea/main.lua

@@ -1,4 +1,5 @@
 require "multis"
+require "e3a.frost"
 
 function apply_fixes()
   local turn = get_turn()
@@ -48,6 +49,7 @@ function process(orders)
   update_embassies()
   update_guards()
   update_scores()
+  frost.update()
 
   local localechange = { de = { "ii" } }
   change_locales(localechange)