Optimization pass for number of tokens used - eliminate unnecessary tables, constants.

mapgen.lua

@@ -2,8 +2,8 @@
 
 function init_mapgen()
    uid_seed = 2229 -- arbitrarily chosen number
-   block_size = 64
-   biome_size = 128
+   -- block_size = 64
+   -- biome_size = 128
 
    -- Metadata for different biomes
    -- frequencies don't have to add up to 100, but they should by convention
@@ -29,10 +29,6 @@ function init_mapgen()
    -- so the biome_metadata array needs to have its entries appear consistently.
    biome_list = {"grassland", "forest", "desert"}
 
-   init_biomes()
-end
-
-function init_biomes()
    -- this is the frequency list for the biomes themselves
    biome_metadata = {}
 
@@ -66,31 +62,33 @@ end
 
 -- generates a unique identifier for a position
 -- uses srand() and rand() to get an unpredictable value (is this too slow?)
-function generate_uid(pos)
-   srand((pos[1] + uid_seed) * (pos[2] + (uid_seed^2)))
-   return flr(rnd(-1))
+-- the two seed values are randomly chosen. Change them and change the world.
+function generate_uid(pos_x, pos_y)
+   srand((pos_x + 2229) * (pos_y + 12295))
+   return flr(rnd(0xffff))
 end
 
 -- given an {x,y} position, calculates the aligned starting position for the
 -- biome that position is in.
-function calculate_biome_pos(pos)
-   return {flr(pos[1] / biome_size), flr(pos[2] / biome_size)}
+-- biomes are currently defined to be 128x128
+function calculate_biome_pos(pos_x, pos_y)
+   return flr(pos_x / 128), flr(pos_y / 128)
 end
 
 -- determines which biome a given world map position should be,
 -- returns the object out of the biome_data table
-function get_biome_name(pos)
-   local biome_pos = calculate_biome_pos(pos)
-   local uid = generate_uid(biome_pos)
+function get_biome_name(pos_x, pos_y)
+   local biome_pos_x, biome_pos_y = calculate_biome_pos(pos_x, pos_y)
+   local uid = generate_uid(biome_pos_x, biome_pos_y)
    return biome_metadata[(uid % #biome_metadata) + 1]
 end
 
 -- determine what sprite to render for a given position.
 -- todo: this needs the ability to have a list of 'changed' tiles to check against.
-function get_tile(pos)
-   local biome_name = get_biome_name(pos)
+function get_tile(pos_x, pos_y)
+   local biome_name = get_biome_name(pos_x, pos_y)
    local biome = biome_data[biome_name]
-   local uid = generate_uid(pos)
+   local uid = generate_uid(pos_x, pos_y)
 
    return biome["tile_lookup"][(uid % #biome["tile_lookup"]) + 1]
 end
@@ -100,10 +98,10 @@ end
 -- writes block_size x block_size tiles
 -- after a call to generate_map you should always center the camera/player over the map, i.e.
 -- camera at { (block_size / 2) - 8, (block_size / 2) - 8 }
-function generate_map(start)
-   for x=0,block_size-1 do
-      for y=0,block_size-1 do
-         mset(x, y, get_tile({start[1]+x, start[2]+y}))
+function generate_map(start_x, start_y)
+   for x=0,63 do
+      for y=0,63 do
+         mset(x, y, get_tile(start_x+x, start_y+y))
       end
    end
 end