remove deprecated module(), better README

README.md

@@ -11,33 +11,35 @@ The heightmap module uses the diamond-square algorithm to generate cloud or plas
 Usage
 -----
 
-    -- import module
-    require "heightmap"
+```lua
+-- import module
+local heightmap = require "heightmap"
 
-    -- create 32x32 heightmap
-    map = heightmap.create(32, 32)
+-- create 32x32 heightmap
+map = heightmap.create(32, 32)
 
-    -- examine each height value
-    for x = 0, map.w do
+-- examine each height value
+for x = 0, map.w do
     for y = 0, map.h do
         print(map[x][y])
     end
-    end
+end
 
-    -- define a custom height function
-    -- (reusing the default but scaling it)
-    function f(map, x, y, d, h)
+-- define a custom height function
+-- (reusing the default but scaling it)
+function f(map, x, y, d, h)
     return 2 * heightmap.defaultf(map, x, y, d, h)
-    end
+end
 
-    -- use it to create a larger non-square heightmap
-    map = heightmap.create(100, 200, f)
+-- use it to create a larger non-square heightmap
+map = heightmap.create(100, 200, f)
 
-    -- create a map with normalized range of -1 to 1
-    map = heightmap.create(150, 300, -1, 1)
+-- create a map with normalized range of -1 to 1
+map = heightmap.create(150, 300, -1, 1)
 
-    -- use the custom height function and normalize with a range of 10 to 20
-    map = heightmap.create(200, 200, f, 10, 20)
+-- use the custom height function and normalize with a range of 10 to 20
+map = heightmap.create(200, 200, f, 10, 20)
+```
 
 How it Works
 ------------

heightmap/heightmap.lua

@@ -3,8 +3,6 @@
 
 local max, random = math.max, math.random
 
-module(...)
-
 -- Find power of two sufficient for size
 local function pot(size)
     local pot = 2
@@ -88,13 +86,13 @@ end
 -- d is depth (from size to 1 by powers of two)
 -- h is mean height at map[x][y] (from square/diamond of radius d)
 -- returns h' which is used to set map[x][y]
-function defaultf(map, x, y, d, h)
+local function defaultf(map, x, y, d, h)
     return h + (random()-0.5)*d
 end
 
 -- Create a heightmap using the specified height function (or default)
 -- map[x][y] where x from 0 to map.w and y from 0 to map.h
-function create(width, height, f)
+local function create(width, height, f)
     f = f and f or defaultf
     -- make heightmap
     local map = diamondsquare(pot(max(width, height)), f)
@@ -104,3 +102,8 @@ function create(width, height, f)
     map.w, map.h = width, height
     return map
 end
+
+return {
+    defaultf = defaultf,
+    create = create
+}