declassify some projects

heavbiome/main.lua

@@ -0,0 +1,93 @@
+local map = {}
+local w = 300
+local h = 300
+local seed = 349259
+require("perlin") -- not mine.
+-- it uses globals. spiteful, but i do not care enough about code quality for this.
+
+
+local biomecols = {
+    empty      = {0.5, 0.5, 0.5},
+    forest     = {  0, 0.5,   0},
+    rainforest = {  0, 0.5, 0.5},
+    ocean      = {  0,   0,   1},
+    plains     = {  0,   1,   0},
+    desert     = {  1,   1,   0},
+}
+
+local PERSISTENCE = 0.3
+local ITERS = 4
+local function oct_noise(x, y, seed, gen)
+    local total = 0
+    local frequency = 1
+    local amplitude = 1
+    local norm = 0
+    for i = 1, ITERS do
+        total = total + gen:noise(x * frequency, y * frequency, seed + i) * amplitude
+        norm = norm + amplitude
+        frequency = frequency * 2
+        amplitude = amplitude * PERSISTENCE
+    end
+    return total
+end
+
+local sf = 1/20 -- scaling factor.
+local function pick_biome(x, y, gen)
+    local islandicity = gen:noise(x*sf/10, y*sf/10, 302382359)/2+1/2
+    islandicity = math.min(math.max(0,islandicity*3),1)
+    local mainland_modifier = gen:noise(x*sf/20, y*sf/20, 302382359)/2
+    local is_ocean = gen:noise(x*sf/4, y*sf/4, 555575)/2+1/2 + gen:noise(x*sf, y*sf, 555575)/(25-islandicity*10) + mainland_modifier
+    local humidity = oct_noise(x*sf/2, y*sf/2, 10000, gen)/2+1/2
+    local temp = oct_noise(x*sf/6, y*sf/6, 20000, gen)/2+1/2
+    --return { is_ocean, humidity, temp }
+    --
+    if is_ocean > 0.45 then return "ocean" end
+    if is_ocean > 0.43 and humidity < 0.6 then return "desert" end -- coast?
+    if temp > 0.75 then return "desert" end
+    if humidity < 0.5 then
+        if temp > 0.5 then
+            return "desert"
+        else
+            return "plains"
+        end
+    else
+        if humidity > 0.75 then
+            return "rainforest"
+        else
+            if temp < 0.6 then
+                return "forest"
+            else
+                return "plains"
+            end
+        end
+    end
+    return "empty"
+    --]]
+end
+
+function love.load()
+    local noise = perlin(seed)
+    local gen = noise
+    for x=1, w do
+        map[x] = {}
+        for y=1, h do
+            map[x][y] = 0
+        end
+    end
+    for x=1, w do
+        for y=1, h do
+            local biome = pick_biome(x, y, noise)
+            --map[x][y] = biome
+            map[x][y] = biomecols[biome]
+        end
+    end
+end
+
+function love.draw()
+    for x=1, w do
+        for y=1, h do
+            love.graphics.setColor(unpack(map[x][y]))
+            love.graphics.rectangle("fill",x*2, y*2, 2, 2)
+        end
+    end
+end

heavbiome/perlin.lua

@@ -0,0 +1,134 @@
+local defaultSeed = 1337
+
+local dot_product = {
+  [0x0]=function(x,y,z) return  x + y end,
+  [0x1]=function(x,y,z) return -x + y end,
+  [0x2]=function(x,y,z) return  x - y end,
+  [0x3]=function(x,y,z) return -x - y end,
+  [0x4]=function(x,y,z) return  x + z end,
+  [0x5]=function(x,y,z) return -x + z end,
+  [0x6]=function(x,y,z) return  x - z end,
+  [0x7]=function(x,y,z) return -x - z end,
+  [0x8]=function(x,y,z) return  y + z end,
+  [0x9]=function(x,y,z) return -y + z end,
+  [0xA]=function(x,y,z) return  y - z end,
+  [0xB]=function(x,y,z) return -y - z end,
+  [0xC]=function(x,y,z) return  y + x end,
+  [0xD]=function(x,y,z) return -y + z end,
+  [0xE]=function(x,y,z) return  y - x end,
+  [0xF]=function(x,y,z) return -y - z end
+}
+
+local grad = function(hash, x,y,z)
+  return dot_product[hash % 0x10](x,y,z)
+end
+
+local fade = function(t)
+  return t * t * t * (t * (t * 6 - 15) + 10)
+end
+
+local lerp = function(t,a,b)
+  return a + t * (b - a)
+end
+
+local generatePermutation = function(seed)
+  math.randomseed(seed)
+
+  local permutation = {0}
+
+  for i=1,255 do
+    table.insert(permutation,math.random(1,#permutation+1),i)
+  end
+
+  local p = {}
+
+  for i=0,255 do
+    p[i] = permutation[i+1]
+    p[i+256] = permutation[i+1]
+  end
+
+  return p
+end
+
+perlin = {}
+perlin.__index = perlin
+
+perlin.noise = function(self,x,y,z)
+  y = y or 0
+  z = z or 0
+
+  local xi = math.floor(x) % 0x100
+  local yi = math.floor(y) % 0x100
+  local zi = math.floor(z) % 0x100
+
+  x = x - math.floor(x)
+  y = y - math.floor(y)
+  z = z - math.floor(z)
+
+  local u = fade(x)
+  local v = fade(y)
+  local w = fade(z)
+
+  local A, AA, AB, AAA, ABA, AAB, ABB, B, BA, BB, BAA, BBA, BAB, BBB
+  A   = self.p[xi  ] + yi
+  AA  = self.p[A   ] + zi
+  AB  = self.p[A+1 ] + zi
+  AAA = self.p[ AA ]
+  ABA = self.p[ AB ]
+  AAB = self.p[ AA+1 ]
+  ABB = self.p[ AB+1 ]
+
+  B   = self.p[xi+1] + yi
+  BA  = self.p[B   ] + zi
+  BB  = self.p[B+1 ] + zi
+  BAA = self.p[ BA ]
+  BBA = self.p[ BB ]
+  BAB = self.p[ BA+1 ]
+  BBB = self.p[ BB+1 ]
+
+  return lerp(w,
+    lerp(v,
+      lerp(u,
+        grad(AAA,x,y,z),
+        grad(BAA,x-1,y,z)
+      ),
+      lerp(u,
+        grad(ABA,x,y-1,z),
+        grad(BBA,x-1,y-1,z)
+      )
+    ),
+    lerp(v,
+      lerp(u,
+        grad(AAB,x,y,z-1), grad(BAB,x-1,y,z-1)
+      ),
+      lerp(u,
+        grad(ABB,x,y-1,z-1), grad(BBB,x-1,y-1,z-1)
+      )
+    )
+  )
+end
+
+setmetatable(perlin,{
+  __call = function(self,seed)
+    seed = seed or defaultSeed
+
+    return setmetatable({
+      seed = seed,
+      p = generatePermutation(seed),
+    },self)
+  end
+})
+
+--[[
+EXAMPLE
+  local p1 = perlin(1338)
+  local p2 = perlin(1337)
+
+  local x,y,z = 1.0,2.0,3.0
+
+  print(p1:noise(x,y,z))
+  print(p2:noise(x,y,z))
+  
+  >> 0.23456
+  >> 0.47598
+--]]