68 lines
2.0 KiB
Lua
68 lines
2.0 KiB
Lua
--- Procedural generation methods
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function init_mapgen()
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uid_seed = 2229 -- arbitrarily chosen number
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block_size = 64
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-- Sprite ratios for different biomes, of the form { "biome_name": {frequency, sprite index} ... } }
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-- frequencies don't have to add up to 100, but they should by convention
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--
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-- Sprites are:
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-- * 2 - grass
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-- * 3 - bush
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-- * 4 - tree
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-- * 5 - red flowers
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-- * 6 - pink flowers
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-- * 7 - mushrooms
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biomes = { grassland = { {40, 2}, {28, 5}, {28, 6}, {3, 3}, {1, 4} },
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forest = { {50, 2}, {40, 4}, {5, 3}, {4, 5}, {1, 7} } }
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build_biome("forest")
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end
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-- use biome1 if mix == false
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function build_biome(biome1, biome2, mix)
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if mix == true then
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else
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frequencies = biomes[biome1]
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end
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-- global variable used for lookup during mapgen
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-- build_biome() writes the biome_lookup table such
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-- that biome_lookup[uid] returns a sprite index,
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-- weighted by the frequency information for current biome.
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biome_lookup = {}
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for i=1,#frequencies do
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local tuple=frequencies[i]
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for j=1,tuple[1] do
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add(biome_lookup, tuple[2])
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end
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end
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end
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-- generates a unique identifier for a position
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-- uses srand() and rand() to get an unpredictable value (is this too slow?)
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function generate_uid(pos)
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srand((pos[1] + uid_seed) * (pos[2] + (uid_seed^2)))
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return flr(rnd(-1))
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end
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-- determine what sprite to render for a given position
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function get_tile(pos)
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return biome_lookup[(generate_uid(pos) % #biome_lookup) + 1]
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end
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-- generate the map and writes to the map area from 0 - block_size,
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-- assuming 'start' as the top-left corner of the map area to generate.
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-- writes block_size x block_size tiles
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-- after a call to generate_map you should always center the camera/player over the map, i.e.
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-- camera at { (block_size / 2) - 8, (block_size / 2) - 8 }
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function generate_map(start)
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for x=0,block_size-1 do
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for y=0,block_size-1 do
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mset(x, y, get_tile({start[1]+x, start[2]+y}))
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end
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end
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end
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