add sand (found near water) and glass

data/entities.yaml

@@ -216,6 +216,24 @@
   properties: [portable]
   capabilities: [float]
 
+- name: sand
+  display:
+    attr: copper
+    char: '░'
+  description:
+  - A substance composed mostly of tiny rocks and mineral particles.  It
+    tends to be found near water, and can be used in a furnace to make glass.
+  properties: [portable, growable]
+  growth: [0,0]
+
+- name: glass
+  display:
+    attr: entity
+    char: '□'
+  description:
+  - A pane of a brittle, clear substance, made from melting sand in a furnace.
+  properties: [portable]
+
 - name: bit (0)
   display:
     attr: entity

data/recipes.yaml

@@ -108,6 +108,13 @@
   required:
   - [1, furnace]
 
+- in:
+  - [1, sand]
+  out:
+  - [1, glass]
+  required:
+  - [1, furnace]
+
 - in:
   - [32, gear]
   - [6, copper wire]

src/Swarm/Game/WorldGen.hs

@@ -66,6 +66,7 @@ testWorld2 baseSeed (Coords ix@(r, c)) =
     | h `mod` 10 == 0 = (StoneT, Just "rock")
     | otherwise = (StoneT, Nothing)
   genBiome Big Soft Natural
+    | abs (sample ix pn1) < 0.1 = (DirtT, Just "sand")
     | even (r + c) = (DirtT, Just "wavy water")
     | otherwise = (DirtT, Just "water")
   genBiome Small Soft Natural