Large refactor to avoid the need to use map() and camera() - the new approach just re-calculates the local world and allows us to scroll 'smoothly' forever.

mapgen.lua

@@ -1,114 +0,0 @@
---- Procedural generation methods
-
-function init_mapgen()
-   uid_seed = 2229 -- arbitrarily chosen number
-
-   -- Metadata for different biomes
-   -- tile_frequencies tuples are {frequency, sprite_index}, see index_map.md
-   -- frequencies by convention add up to 1000, but this is arbitrary, the
-   -- only concern is the space consumed by the resulting tables.
-   biome_data = {
-      meadow = {
-         biome_frequency = 20,
-         tile_frequencies = { {525, 2}, {200, 5}, {200, 6}, {55, 18}, {19, 3}, {1, 4} }
-      },
-      grassland = {
-         biome_frequency = 55,
-         tile_frequencies = { {500, 2}, {345, 18}, {4, 3}, {1, 4}, {100, 5}, {50, 6} }
-      },
-      forest = {
-         biome_frequency = 20,
-         tile_frequencies = { {600, 2}, {200, 4}, {50, 3}, {50, 5}, {40, 7}, {59, 6}, {1, 8} }
-      },
-      desert = {
-         biome_frequency = 5,
-         tile_frequencies = { {800, 9}, {109, 11}, {60, 13}, {30, 12}, {1, 10} },
-      }
-   }
-
-   -- Why is this hard-coded separately from the biome_data? glad you asked.
-   -- Lua's pairs() function appears not to guarantee a consistent return order,
-   -- and we want our world to be deterministically generated,
-   -- so the biome_metadata array needs to have its entries appear consistently.
-   biome_list = {"grassland", "meadow", "forest", "desert"}
-
-   -- this is the frequency list for the biomes themselves
-   biome_metadata = {}
-
-   for i=1,#biome_list do
-      local biome = biome_list[i]
-
-      -- add the biome's name N times to the biome metadata 'hat'
-      for i=1,biome_data[biome].biome_frequency do
-         add(biome_metadata, biome)
-      end
-
-      build_biome(biome, biome_data[biome])
-   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(tile_lookup, tuple[2])
-      end
-   end
-
-   data.tile_lookup = tile_lookup
-end
-
--- generates a unique identifier for a position
--- uses srand() and rand() to get an unpredictable value (is this too slow?)
--- 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.
--- 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_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.
--- pos_x and pos_y are global coordinates.
-function get_tile(pos_x, pos_y)
-   -- lookup changes in the change buffer
-   local modded_sprite = mod_buffer[get_mod_key(pos_x, pos_y)]
-   if (modded_sprite) return modded_sprite
-
-   local biome_name = get_biome_name(pos_x, pos_y)
-   local biome = biome_data[biome_name]
-   local uid = generate_uid(pos_x, pos_y)
-
-   return biome.tile_lookup[(uid % #biome.tile_lookup) + 1]
-end
-
--- generate the map and writes to the map area from 0 - block_size,
--- assuming 'start' as the top-left corner of the map area to generate.
--- 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_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