Implement multiple biomes.

infimap.p8

@@ -5,14 +5,14 @@ __lua__
 #include player.lua
 #include main.lua
 __gfx__
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@@ -70,5 +70,5 @@ __gfx__
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 00000000000000000000000000000000000000000000000000000000000000000000000000077000000700000000700000000000000000000777700000077770
 __gff__
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mapgen.lua

@@ -3,8 +3,9 @@
 function init_mapgen()
    uid_seed = 2229 -- arbitrarily chosen number
    block_size = 64
+   biome_size = 128
 
-   -- Sprite ratios for different biomes, of the form { "biome_name": {frequency, sprite index} ... } }
+   -- Metadata for different biomes
    -- frequencies don't have to add up to 100, but they should by convention
    --
    -- Sprites are:
@@ -14,31 +15,58 @@ function init_mapgen()
    --  * 5 - red flowers
    --  * 6 - pink flowers
    --  * 7 - mushrooms
-   biomes = { grassland = { {40, 2}, {28, 5}, {28, 6}, {3, 3}, {1, 4} },
+   --  * 8 - big mushroom
-              forest = { {55, 2}, {25, 4}, {5, 3}, {5, 5}, {5, 7}, {5, 6} },
+   --  * 9 - sand
-            }
+   --  * 10 - cactus with flower
+   --  * 11 - pebbles
+   --  * 12 - rock
+   --  * 13 - cactus
+   biome_data = {
+      grassland = {
+         biome_frequency = 75,
+         tile_frequencies = { {40, 2}, {28, 5}, {28, 6}, {3, 3}, {1, 4} }
+      },
+      forest = {
+         biome_frequency = 20,
+         tile_frequencies = { {60, 2}, {20, 4}, {5, 3}, {5, 5}, {4, 7}, {5, 6}, {1, 8} }
+      },
+      desert = {
+         biome_frequency = 5,
+         tile_frequencies = { {80, 9}, {10, 11}, {6, 13}, {3, 12}, {1, 10} },
+      }
+   }
 
-   build_biome("forest")
+   init_biomes()
 end
 
--- use biome1 if mix == false
+function init_biomes()
-function build_biome(biome1, biome2, mix)
+   -- this is the frequency list for the biomes themselves
-   if mix == true then
+   biome_metadata = {}
-   else
-      frequencies = biomes[biome1]
-   end
 
-   -- global variable used for lookup during mapgen
+   for k,v in pairs(biome_data) do
-   -- build_biome() writes the biome_lookup table such
+      -- add the biome's name N times to the biome metadata 'hat'
-   -- that biome_lookup[uid] returns a sprite index,
+      for i=1,v["biome_frequency"] do
-   -- weighted by the frequency information for current biome.
+         add(biome_metadata, k)
-   biome_lookup = {}
+      end
-   for i=1,#frequencies do
+
-      local tuple=frequencies[i]
+      build_biome(k, v)
+   end
+end
+
+-- build the lookup table for a given biome, based on the biome_meta data for
+-- that string.
+function build_biome(biome_name, data)
+   local meta_frequencies = data["tile_frequencies"]
+   local tile_lookup = {}
+
+   for i=1,#meta_frequencies do
+      local tuple = meta_frequencies[i]
       for j=1,tuple[1] do
-         add(biome_lookup, tuple[2])
+         add(tile_lookup, tuple[2])
       end
    end
+
+   data["tile_lookup"] = tile_lookup
 end
 
 -- generates a unique identifier for a position
@@ -48,9 +76,22 @@ function generate_uid(pos)
    return flr(rnd(-1))
 end
 
--- determine what sprite to render for a given position
+-- determines which biome a given world map position should be,
+-- returns the object out of the biome_data table
+function get_biome(pos)
+   local biome_pos = {flr(pos[1] / biome_size), flr(pos[2] / biome_size)}
+   local uid = generate_uid(biome_pos)
+   local biome_name = biome_metadata[(uid % #biome_metadata) + 1]
+   return biome_data[biome_name]
+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)
-   return biome_lookup[(generate_uid(pos) % #biome_lookup) + 1]
+   local biome = get_biome(pos)
+   local uid = generate_uid(pos)
+
+   return biome["tile_lookup"][(uid % #biome["tile_lookup"]) + 1]
 end
 
 -- generate the map and writes to the map area from 0 - block_size,

player.lua

@@ -1,5 +1,5 @@
--- this module assumes all objects and the player are
+-- This module assumes all objects and the player are 1x1 sprite in size.
--- 1x1 sprite in size. larger sprites are not currently supported
+-- Larger sprites will probably work for objects, but not for the player.
 --
 -- exported variables:
 --   player_pos # integer tuple {x,y}. absolute position of the player on the
@@ -10,10 +10,6 @@
 --              #   each element can be -1 (up or left), 0 (neutral),
 --              #   or 1 (down or right)
 --
--- exported constants:
---   player_lookup # used internally to look up the sprite to render for a
---                 #   given facing
---
 -- functions:
 --   init_player({x,y}) # call this in _init(). Sets player starting position,
 --                      #   assumes the top-left of the pico-8 map is currently
@@ -23,14 +19,9 @@
 --   draw_player()      # call in _draw(). Draws the player sprite.
 
 function init_player(start_pos)
-   -- camera_pos is the relative coordinate of the camera
-   -- on the currently generated map chunk. player_pos is
-   -- the *absolute* world coordinates of the player.
    player_pos = start_pos
    camera_pos = {start_pos[1]-8, start_pos[2]-8}
 
-   -- [1] is vertical facing, [2] is horizontal, -1 is up/left, 0 is neutral,
-   -- and 1 is down/right
    facing = {1, 0}
 
    -- this is a constant for looking up player sprites by facing