temperature affected by latitude, non-linearly

ReadMe.md

@@ -8,14 +8,22 @@ Using the heightmap generator from here: https://github.com/TangentFoxy/heightma
 - [ ] Remove heightmap library
   - [ ] Update ReadMe
   - [ ] ReadMe should also point out where the simplex implementation comes from
-- [ ] Update the `simplex` library to the latest version with FBM
-- [ ] Round the new map generator to a planet shape
+- [x] Update the `simplex` library to the latest version with FBM
+- [x] Round the new map generator to a planet shape
 - [ ] Move `tile_size` out of the map generator (this is a render feature, not a map feature)
-- [ ] Turn the new map gen into a wrapper kind of like my heightmap wrapper? (This is sorta already done in a sloppy way.)
+- [x] Turn the new map gen into a wrapper kind of like my heightmap wrapper? (This is sorta already done in a sloppy way.)
 - [ ] Rebuild the multi-noise map system.
   - [ ] Renormalize to Earth extremes. :D (This will probably give bad initial results and need extensive changes.)
-  - [ ] Use a spreadsheet to map -0.9 to 0.9 to find a mapping function to modify initial values to realistic height ranges!
-  - [ ] Rename `humidity` to `rainfall`.
+  - [x] Use a spreadsheet to map -0.9 to 0.9 to find a mapping function to modify initial values to realistic height ranges!
+    (This was done with -1 to 1)
+  - [x] Rename `humidity` to `rainfall`.
 - [ ] make documentation of how this is all working so I can remember when I forget to work on it for a while
 
+### Long-Term
+- [ ] Do all terrain generation within a radius check so unnecessary work isn't done and discarded.
+  - [ ] Terrain generation steps should happen within a single loop wherever possible?
+
+## Reference
+- Out of 52 seeds randomly tested, the current code creates a temperature range between -80.64 and 33.78 C.
+
 (Tasks/Issues are stored in the ReadMe instead of using a webUI issue tracker due to how using such a tracker negatively influences portability of the project.)

disorganized biome notes.txt

@@ -0,0 +1,62 @@
+DDG summary:
+aquatic -> freshwater / marine,
+grassland (2nd largest?),
+forest -> tropical / temperate,
+desert,
+tundra,
+
+---
+
+Wikipedia:
+ice sheet / polar desert,
+tundra (tree growth hindered by cold and short growing seasons; arctic, alpine, antarctic; shrubs, grasses, mosses, lichen; soil high N & P, biomass, methane, CO2, permafrost),
+taiga (boreal forest, snow forest, coniferous forest; pines, spruces, larches; largest land biome),
+temperate broadleaf forest,
+temperate steppe and savanna,
+subtropical evergreen forest,
+Mediterranean vegetation,
+monsoon forests and mosaic,
+arid desert,
+xeric shrubland,
+dry steppe and thorn forest,
+semiarid desert,
+grass savanna,
+tree savanna,
+dry forest and woodland savanna,
+tropical rainforest (evergreen?),
+alpine tundra,
+montane forests and grasslands,
+- what variables control whether it develops a forest or grassland?
+
+alts:
+deciduous forest (not evergreen - can be cold or dry to cause leaves to fall; trees, shrubs, perennials),
+high plateaus (flat raised plains),
+
+---
+
+savanna seems to just mean grassland with some shrubs and trees? (dry)
+steppe is grasslands with NO trees (dry, often cold)
+meadow is wet grasslands
+hypoxic / anoxic waters FORM dead zones (nutrient concentration -> bloom, low water movement, high temperature; deepest waters?), gyre centers (ocean currents)
+- use of absolute deepest water as a shortcut should be fine,
+- use of highest temperature in water would also be a decent shortcut
+
+("continentalness" may be useful)
+
+tropical just means low latitude - these are small
+montane just means mountain
+
+(one mm of rainfall == 1 L/m^3)
+
+---
+
+coastal forest? (tropical moist broadleaf)
+montanes are often forested?
+what's the difference between a swamp and marsh? and bog?
+I should sprinkle volcanoes in (but that would work better with some kind of fault sim)
+- these form jungle/forest easier? more nutrients in soil
+what's a moorland?
+jungle vs rainforest?
+
+rifts and rivers?
+temperature should decrease by 0.0065 per meter (but this only holds above water?)

src/lib/running_average.lua

@@ -0,0 +1,27 @@
+local running_average = {
+  trackers = {}
+}
+
+local trackers = running_average.trackers
+
+running_average.track = function(name, value)
+  if not trackers[name] then
+    trackers[name] = { running_total = 0, count = 0, }
+  end
+  local track = trackers[name]
+
+  track.running_total = track.running_total + value
+  track.count = track.count + 1
+
+  return track.running_total / track.count
+end
+
+running_average.average = function(name)
+  return trackers[name] and trackers[name].running_total / trackers[name].count
+end
+
+running_average.count = function(name)
+  return trackers[name] and trackers[name].count
+end
+
+return running_average

src/lib/simplex.lua

@@ -82,14 +82,14 @@ local sim = {
 {2,1,0,3},{0,0,0,0},{0,0,0,0},{0,0,0,0},{3,1,0,2},{0,0,0,0},{3,2,0,1},{3,2,1,0}};
 
 local function Dot2D(tbl, x, y)
-	return tbl[1]*x + tbl[2]*y; 
+	return tbl[1]*x + tbl[2]*y;
 end
 
 local function Dot3D(tbl, x, y, z)
 	return tbl[1]*x + tbl[2]*y + tbl[3]*z
 end
 
-local function Dot4D( tbl, x,y,z,w) 
+local function Dot4D( tbl, x,y,z,w)
 	return tbl[1]*x + tbl[2]*y + tbl[3]*z + tbl[3]*w;
 end
 
@@ -99,7 +99,7 @@ local Prev2D = {}
 -- 2D simplex noise
 
 function simplex.Noise2D(xin, yin)
-	if simplex.internalCache and Prev2D[xin] and Prev2D[xin][yin] then return Prev2D[xin][yin] end 
+	if simplex.internalCache and Prev2D[xin] and Prev2D[xin][yin] then return Prev2D[xin][yin] end
 
 	local n0, n1, n2; -- Noise contributions from the three corners
 	-- Skew the input space to determine which simplex cell we're in
@@ -108,24 +108,24 @@ function simplex.Noise2D(xin, yin)
 	local i = math.floor(xin+s);
 	local j = math.floor(yin+s);
 	local G2 = (3.0-math.sqrt(3.0))/6.0;
-	
+
 	local t = (i+j)*G2;
 	local X0 = i-t; -- Unskew the cell origin back to (x,y) space
 	local Y0 = j-t;
 	local x0 = xin-X0; -- The x,y distances from the cell origin
 	local y0 = yin-Y0;
-	
+
 	-- For the 2D case, the simplex shape is an equilateral triangle.
 	-- Determine which simplex we are in.
 	local i1, j1; -- Offsets for second (middle) corner of simplex in (i,j) coords
-	if(x0>y0) then 
-		i1=1 
+	if(x0>y0) then
+		i1=1
 		j1=0  -- lower triangle, XY order: (0,0)->(1,0)->(1,1)
 	else
 		i1=0
 		j1=1 -- upper triangle, YX order: (0,0)->(0,1)->(1,1)
 	end
-	
+
 	-- A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
 	-- a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
 	-- c = (3-sqrt(3))/6
@@ -144,13 +144,13 @@ function simplex.Noise2D(xin, yin)
 
 	-- Calculate the contribution from the three corners
 	local t0 = 0.5 - x0*x0-y0*y0;
-	if t0<0 then 
+	if t0<0 then
 		n0 = 0.0;
 	else
 		t0 = t0 * t0
 		n0 = t0 * t0 * Dot2D(Gradients3D[gi0], x0, y0); -- (x,y) of Gradients3D used for 2D gradient
 	end
-	
+
 	local t1 = 0.5 - x1*x1-y1*y1;
 	if (t1<0) then
 		n1 = 0.0;
@@ -158,7 +158,7 @@ function simplex.Noise2D(xin, yin)
 		t1 = t1*t1
 		n1 = t1 * t1 * Dot2D(Gradients3D[gi1], x1, y1);
 	end
-	
+
 	local t2 = 0.5 - x2*x2-y2*y2;
 	if (t2<0) then
 		n2 = 0.0;
@@ -167,17 +167,17 @@ function simplex.Noise2D(xin, yin)
 		n2 = t2 * t2 * Dot2D(Gradients3D[gi2], x2, y2);
 	end
 
-	
+
 	-- Add contributions from each corner to get the final noise value.
 	-- The result is scaled to return values in the localerval [-1,1].
-	
+
 	local retval = 70.0 * (n0 + n1 + n2)
-	
+
 	if simplex.internalCache then
 		if not Prev2D[xin] then Prev2D[xin] = {} end
 		Prev2D[xin][yin] = retval
 	end
-	
+
 	return retval;
 end
 
@@ -185,127 +185,127 @@ local Prev3D = {}
 
 -- 3D simplex noise
 function simplex.Noise3D(xin, yin, zin)
-	
+
 	if simplex.internalCache and Prev3D[xin] and Prev3D[xin][yin] and Prev3D[xin][yin][zin] then return Prev3D[xin][yin][zin] end
-	
+
 	local n0, n1, n2, n3; -- Noise contributions from the four corners
-	
+
 	-- Skew the input space to determine which simplex cell we're in
 	local F3 = 1.0/3.0;
 	local s = (xin+yin+zin)*F3; -- Very nice and simple skew factor for 3D
 	local i = math.floor(xin+s);
 	local j = math.floor(yin+s);
 	local k = math.floor(zin+s);
-	
+
 	local G3 = 1.0/6.0; -- Very nice and simple unskew factor, too
 	local t = (i+j+k)*G3;
-	
+
 	local X0 = i-t; -- Unskew the cell origin back to (x,y,z) space
 	local Y0 = j-t;
 	local Z0 = k-t;
-	
+
 	local x0 = xin-X0; -- The x,y,z distances from the cell origin
 	local y0 = yin-Y0;
 	local z0 = zin-Z0;
-	
+
 	-- For the 3D case, the simplex shape is a slightly irregular tetrahedron.
 	-- Determine which simplex we are in.
 	local i1, j1, k1; -- Offsets for second corner of simplex in (i,j,k) coords
 	local i2, j2, k2; -- Offsets for third corner of simplex in (i,j,k) coords
-	
+
 	if (x0>=y0) then
 		if (y0>=z0) then
 			i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; -- X Y Z order
 		elseif (x0>=z0) then
 			i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; -- X Z Y order
-		else 
+		else
 			i1=0; j1=0; k1=1; i2=1; j2=0; k2=1;  -- Z X Y order
 		end
 	else -- x0<y0
-		if (y0<z0) then 
+		if (y0<z0) then
 			i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; -- Z Y X order
-		elseif (x0<z0) then 
+		elseif (x0<z0) then
 			i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; -- Y Z X order
-		else 
+		else
 			i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; -- Y X Z order
 		end
 	end
-	
+
 	-- A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
 	-- a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
 	-- a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
 	-- c = 1/6.
-	
+
 	local x1 = x0 - i1 + G3; -- Offsets for second corner in (x,y,z) coords
 	local y1 = y0 - j1 + G3;
 	local z1 = z0 - k1 + G3;
-	
+
 	local x2 = x0 - i2 + 2.0*G3; -- Offsets for third corner in (x,y,z) coords
 	local y2 = y0 - j2 + 2.0*G3;
 	local z2 = z0 - k2 + 2.0*G3;
-	
+
 	local x3 = x0 - 1.0 + 3.0*G3; -- Offsets for last corner in (x,y,z) coords
 	local y3 = y0 - 1.0 + 3.0*G3;
 	local z3 = z0 - 1.0 + 3.0*G3;
-	
+
 	-- Work out the hashed gradient indices of the four simplex corners
 	local ii = math.floor(i % 255)
 	local jj = math.floor(j % 255)
 	local kk = math.floor(k % 255)
-	
+
 	local gi0 = perm[ii+perm[jj+perm[kk]]] % 12;
 	local gi1 = perm[ii+i1+perm[jj+j1+perm[kk+k1]]] % 12;
 	local gi2 = perm[ii+i2+perm[jj+j2+perm[kk+k2]]] % 12;
 	local gi3 = perm[ii+1+perm[jj+1+perm[kk+1]]] % 12;
-	
+
 	-- Calculate the contribution from the four corners
 	local t0 = 0.5 - x0*x0 - y0*y0 - z0*z0;
-	
+
 	if (t0<0) then
 		n0 = 0.0;
-	else 
+	else
 		t0 = t0*t0;
 		n0 = t0 * t0 * Dot3D(Gradients3D[gi0], x0, y0, z0);
 	end
-	
+
 	local t1 = 0.5 - x1*x1 - y1*y1 - z1*z1;
-	
-	if (t1<0) then 
+
+	if (t1<0) then
 		n1 = 0.0;
 	else
 		t1 = t1*t1;
 		n1 = t1 * t1 * Dot3D(Gradients3D[gi1], x1, y1, z1);
 	end
-	
+
 	local t2 = 0.5 - x2*x2 - y2*y2 - z2*z2;
-	
-	if (t2<0) then 
+
+	if (t2<0) then
 		n2 = 0.0;
 	else
 		t2 = t2*t2;
 		n2 = t2 * t2 * Dot3D(Gradients3D[gi2], x2, y2, z2);
 	end
-	
+
 	local t3 = 0.5 - x3*x3 - y3*y3 - z3*z3;
-	
-	if (t3<0) then 
+
+	if (t3<0) then
 		n3 = 0.0;
 	else
 		t3 = t3*t3;
 		n3 = t3 * t3 * Dot3D(Gradients3D[gi3], x3, y3, z3);
 	end
-	
-	
+
+
 	-- Add contributions from each corner to get the final noise value.
 	-- The result is scaled to stay just inside [-1,1]
 	local retval = 32.0*(n0 + n1 + n2 + n3)
-	
+
 	if simplex.internalCache then
 		if not Prev3D[xin] then Prev3D[xin] = {} end
 		if not Prev3D[xin][yin] then Prev3D[xin][yin] = {} end
 		Prev3D[xin][yin][zin] = retval
 	end
-	
+
 	return retval;
 end
 
@@ -315,7 +315,7 @@ local Prev4D = {}
 function simplex.Noise4D(x,y,z,w)
 
 	if simplex.internalCache and Prev4D[x] and Prev4D[x][y] and Prev4D[x][y][z] and Prev4D[x][y][z][w] then return Prev4D[x][y][z][w] end
-	
+
 	-- The skewing and unskewing factors are hairy again for the 4D case
 	local F4 = (math.sqrt(5.0)-1.0)/4.0;
 	local G4 = (5.0-math.sqrt(5.0))/20.0;
@@ -353,13 +353,13 @@ function simplex.Noise4D(x,y,z,w)
 	local i1, j1, k1, l1; -- The localeger offsets for the second simplex corner
 	local i2, j2, k2, l2; -- The localeger offsets for the third simplex corner
 	local i3, j3, k3, l3; -- The localeger offsets for the fourth simplex corner
-	
+
 	-- sim[c] is a 4-vector with the numbers 0, 1, 2 and 3 in some order.
 	-- Many values of c will never occur, since e.g. x>y>z>w makes x<z, y<w and x<w
 	-- impossible. Only the 24 indices which have non-zero entries make any sense.
 	-- We use a thresholding to set the coordinates in turn from the largest magnitude.
 	-- The number 3 in the "sim" array is at the position of the largest coordinate.
-	
+
 	i1 = sim[c][1]>=3 and 1 or 0;
 	j1 = sim[c][2]>=3 and 1 or 0;
 	k1 = sim[c][3]>=3 and 1 or 0;
@@ -391,7 +391,7 @@ function simplex.Noise4D(x,y,z,w)
 	local y4 = y0 - 1.0 + 4.0*G4;
 	local z4 = z0 - 1.0 + 4.0*G4;
 	local w4 = w0 - 1.0 + 4.0*G4;
-	
+
 	-- Work out the hashed gradient indices of the five simplex corners
 	local ii = math.floor(i % 255)
 	local jj = math.floor(j % 255)
@@ -402,8 +402,8 @@ function simplex.Noise4D(x,y,z,w)
 	local gi2 = perm[ii+i2+perm[jj+j2+perm[kk+k2+perm[ll+l2]]]] % 32;
 	local gi3 = perm[ii+i3+perm[jj+j3+perm[kk+k3+perm[ll+l3]]]] % 32;
 	local gi4 = perm[ii+1+perm[jj+1+perm[kk+1+perm[ll+1]]]] % 32;
-	
-	
+
+
 	-- Calculate the contribution from the five corners
 	local t0 = 0.5 - x0*x0 - y0*y0 - z0*z0 - w0*w0;
 	if (t0<0) then
@@ -412,15 +412,15 @@ function simplex.Noise4D(x,y,z,w)
 		t0 = t0*t0;
 		n0 = t0 * t0 * Dot4D(Gradients4D[gi0], x0, y0, z0, w0);
 	end
-	
+
 	local t1 = 0.5 - x1*x1 - y1*y1 - z1*z1 - w1*w1;
 	if (t1<0) then
 		n1 = 0.0;
-	else 
+	else
 		t1 = t1*t1;
 		n1 = t1 * t1 * Dot4D(Gradients4D[gi1], x1, y1, z1, w1);
 	end
-	
+
 	local t2 = 0.5 - x2*x2 - y2*y2 - z2*z2 - w2*w2;
 	if (t2<0) then
 		n2 = 0.0;
@@ -428,15 +428,15 @@ function simplex.Noise4D(x,y,z,w)
 		t2 = t2*t2;
 		n2 = t2 * t2 * Dot4D(Gradients4D[gi2], x2, y2, z2, w2);
 	end
-	
+
 	local t3 = 0.5 - x3*x3 - y3*y3 - z3*z3 - w3*w3;
 	if (t3<0) then
 		n3 = 0.0;
-	else 
+	else
 		t3 = t3*t3;
 		n3 = t3 * t3 * Dot4D(Gradients4D[gi3], x3, y3, z3, w3);
 	end
-	
+
 	local t4 = 0.5 - x4*x4 - y4*y4 - z4*z4 - w4*w4;
 	if (t4<0) then
 		n4 = 0.0;
@@ -444,22 +444,22 @@ function simplex.Noise4D(x,y,z,w)
 		t4 = t4*t4;
 		n4 = t4 * t4 * Dot4D(Gradients4D[gi4], x4, y4, z4, w4);
 	end
-	
+
 	-- Sum up and scale the result to cover the range [-1,1]
-	
+
 	local retval = 27.0 * (n0 + n1 + n2 + n3 + n4)
-	
+
 	if simplex.internalCache then
 		if not Prev4D[x] then Prev4D[x] = {} end
 		if not Prev4D[x][y] then Prev4D[x][y] = {} end
 		if not Prev4D[x][y][z] then Prev4D[x][y][z] = {} end
 		Prev4D[x][y][z][w] = retval
 	end
-	
+
 	return retval;
 
 
-end 
+end
 
 local e = 2.71828182845904523536
 
@@ -469,14 +469,14 @@ function simplex.GBlur2D(x,y,stdDev)
 	if simplex.internalCache and PrevBlur2D[x] and PrevBlur2D[x][y] and PrevBlur2D[x][y][stdDev] then return PrevBlur2D[x][y][stdDev] end
 	local pwr = ((x^2+y^2)/(2*(stdDev^2)))*-1
 	local ret = (1/(2*math.pi*(stdDev^2)))*(e^pwr)
-	
+
 	if simplex.internalCache then
 		if not PrevBlur2D[x] then PrevBlur2D[x] = {} end
 		if not PrevBlur2D[x][y] then PrevBlur2D[x][y] = {} end
 		PrevBlur2D[x][y][stdDev] = ret
 	end
 	return ret
-end 
+end
 
 local PrevBlur1D = {}
 
@@ -497,7 +497,7 @@ function simplex.FractalSum(func, iter, ...)
     for i=1,iter do
         local power = 2^iter
         local s = power/i
-        
+
         local scaled = {}
         for elem in ipairs({...}) do
             table.insert(scaled, elem*s)
@@ -512,7 +512,7 @@ function simplex.FractalSumAbs(func, iter, ...)
     for i=1,iter do
         local power = 2^iter
         local s = power/i
-        
+
         local scaled = {}
         for elem in ipairs({...}) do
             table.insert(scaled, elem*s)
@@ -527,7 +527,7 @@ function simplex.Turbulence(func, direction, iter, ...)
     for i=1,iter do
         local power = 2^iter
         local s = power/i
-        
+
         local scaled = {}
         for elem in ipairs({...}) do
             table.insert(scaled, elem*s)
@@ -556,4 +556,21 @@ function simplex.Seed(seed)
     end
 end
 
+-- TODO test functionality
+function simplex.FractalBrownianMotion2D(x, y, octaves, lacunarity, gain)
+    octaves = octaves or 4
+    lacunarity = lacunarity or 2
+    gain = gain or 0.5
+
+    local total, amplitude, frequency, peak_amplitude = 0, 1, 1, 0
+    for i = 1, octaves do
+        total = total + amplitude * simplex.Noise2D(x * frequency, y * frequency)
+        peak_amplitude = peak_amplitude + amplitude
+        amplitude = amplitude * gain
+        frequency = frequency * lacunarity
+    end
+
+    return total / peak_amplitude   -- normalize to [-1, 1]
+end
+
 return simplex

src/lib/simplex_map.lua

@@ -0,0 +1,77 @@
+local simplex = require "lib.simplex"
+
+local simplex_map = {}
+
+simplex_map.min = function(map)
+  local r = math.huge
+  for i=1,#map do
+    if map[i] then
+      for j=1,#map[1] do
+        local v = map[i][j]
+        if v and r > v then r = v end
+      end
+    end
+  end
+  return r
+end
+simplex_map.max = function(map)
+  local r = -math.huge
+  for i=1,#map do
+    if map[i] then
+      for j=1,#map[1] do
+        local v = map[i][j]
+        if v and r < v then r = v end
+      end
+    end
+  end
+  return r
+end
+
+simplex_map.normalize = function(map, new_min, new_max)
+  local minimum = simplex_map.min(map)
+  local initialRange = simplex_map.max(map) - minimum
+  local finalRange = new_max - new_min
+  for i = 1, #map do
+    for j = 1, #map[1] do
+      map[i][j] = (map[i][j] - minimum) / initialRange * finalRange + new_min
+    end
+  end
+  map.min = simplex_map.min(map)
+  map.max = simplex_map.max(map)
+  return map -- superfluous
+end
+
+simplex_map.generate = function(size, scale, min, max, octaves, lacunarity, gain)
+  if type(size) == "table" then
+    scale = size.scale
+    min = size.min
+    max = size.max
+    octaves = size.octaves
+    lacunarity = size.lacunarity
+    gain = size.gain
+
+    size = size.size
+  end
+
+  simplex.Seed(math.random())
+  local map = {}
+  map.size = size
+
+  scale = scale or 0.005
+  for x = 1, map.size do
+    map[x] = {}
+    for y = 1, map.size do
+      map[x][y] = simplex.FractalBrownianMotion2D(x * scale, y * scale, octaves, lacunarity, gain)
+    end
+  end
+
+  if min or max then
+    min = min or 0
+    max = max or 1
+    simplex_map.normalize(map, min, max)
+  end
+
+  return map
+end
+
+return simplex_map

src/main.lua

@@ -1,11 +1,19 @@
+math.randomseed(os.time())
+
 local map_generator = require "map_nextgen"
 local lovebird = require "lib.lovebird"
 local lume = require "lib.lume"
+local running_average = require "lib.running_average"
+local simplex_map = require "lib.simplex_map"
 
 local map
 
 love.load = function()
   map = map_generator.generate()
+  map.temperature.min = simplex_map.min(map.temperature)
+  map.temperature.max = simplex_map.max(map.temperature)
+  print("Min Temperature", map.temperature.min, "Average", running_average.track("minT", map.temperature.min))
+  print("Max Temperature", map.temperature.max, "Average", running_average.track("maxT", map.temperature.max))
 
   -- if true then return end
 
@@ -66,10 +74,11 @@ love.draw = function()
 
   for x = 1, map.size do
     for y = 1, map.size do
-      -- print(x, y) -- TEMP why am I getting an out of bounds?
-      local value = map.terrain[x][y]
+      -- local value = map.biome[x][y]
+      local value = map.temperature[x][y]
       if value then
-        love.graphics.setColor(value)
+        -- love.graphics.setColor(value)
+        love.graphics.setColor( (value + map.temperature.max) / (map.temperature.max + math.abs(map.temperature.min)) , 0, 0, 1)
         love.graphics.rectangle("fill", x * map.tile_size, y * map.tile_size, map.tile_size, map.tile_size)
       end
     end
@@ -81,5 +90,9 @@ love.keypressed = function(key)
     love.event.quit()
   elseif key == "r" then
     love.load()
+  elseif key == "=" then
+    map.tile_size = map.tile_size * 2
+  elseif key == "-" then
+    map.tile_size = map.tile_size / 2
   end
 end

src/map_nextgen.lua

@@ -1,73 +1,135 @@
 -- NOTE the API of this file should probably change?
 
-local simplex = require "lib.simplex"
+local lume = require "lib.lume"
+local simplex_map = require "lib.simplex_map"
+
+local biomes = {
+  -- biomes are checked in order, with the first candidate always being selected
+  [900] = {
+    name = "deep ocean",
+    altitude = {min = -math.huge, max = -5000},
+    temperature = {min = -math.huge, max = math.huge},
+    rainfall = {min = -math.huge, max = math.huge},
+    color = {0, 0, 0.25, 1},
+  },
+  [1000] = {
+    name = "ocean (definition, 0 meters)",
+    altitude = {min = -math.huge, max = 0},
+    temperature = {min = -math.huge, max = math.huge},
+    rainfall = {min = -math.huge, max = math.huge},
+    color = {0, 0, 0.5, 1},
+  },
+  [2000] = {
+    name = "snowline (middle estimate)",
+    altitude = {min = 4000, max = math.huge},
+    temperature = {min = -math.huge, max = math.huge},
+    rainfall = {min = -math.huge, max = math.huge},
+    color = {1, 1, 1, 1},
+  },
+  [2100] = {
+    name = "alpine zone",
+    altitude = {min = 3500, max = math.huge},
+    temperature = {min = -math.huge, max = math.huge},
+    rainfall = {min = -math.huge, max = math.huge},
+    color = {0.8, 0.8, 0.8, 1},
+  },
+  [2200] = {
+    name = "subalpine zone",
+    altitude = {min = 3000, max = math.huge},
+    temperature = {min = -math.huge, max = math.huge},
+    rainfall = {min = -math.huge, max = math.huge},
+    color = {0.67, 0.67, 0.67, 1},
+  },
+  [2300] = {
+    name = "montane zone",
+    altitude = {min = 2500, max = math.huge},
+    temperature = {min = -math.huge, max = math.huge},
+    rainfall = {min = -math.huge, max = math.huge},
+    color = {0.67, 0.67, 0.5, 1},
+  },
+}
 
 local generate = function()
-  simplex.Seed(math.random())
-
   local map = {}
   map.size = 500
   map.tile_size = 1 -- TODO tile_size really shouldn't be the responsibility of the map generator - it's a rendering detail, not a map feature
-  map.altitude = {} -- TEMP only one noise map
+  map.altitude = simplex_map.generate{   -- will be converted to meters
+    size = map.size, scale = 0.001, min = 0, max = 1,
+    octaves = 7, lacunarity = 2, gain = 0.5,
+  }
+  map.temperature = simplex_map.generate{   -- in celsius
+    -- -20 to 45 chosen by looking at the temperature range shown on https://openclimatemap.org/
+    size = map.size, scale = 0.005, min = -20, max = 45, -- approximate target extremes of -89.2 to 56.7
+    octaves = 1, lacunarity = 2, gain = 0.5,
+  }
+  map.rainfall = simplex_map.generate{   -- in millimeters of rainfall
+    size = map.size, scale = 0.005, -- min = 18, max = 3240,
+    octaves = 1, lacunarity = 2, gain = 0.5,
+  }
+
+  local function earthlike_altitude_adjustment(altitude)
+    -- TODO replace with a simpler function?
+    return 6099 - 114909 * altitude + 830891 * altitude^2 - 2.72e6 * altitude^3 + 4.19e6 * altitude^4 - 3.02e6 * altitude^5 + 815866 * altitude^6
+  end
 
-  local scale = 0.005
-  local min, max = math.huge, -math.huge
   for x = 1, map.size do
-    map.altitude[x] = {}
     for y = 1, map.size do
-      local value = simplex.Noise2D(x * scale, y * scale)
-      if value > max then max = value end
-      if value < min then min = value end
-      map.altitude[x][y] = value
+      map.altitude[x][y] = earthlike_altitude_adjustment(map.altitude[x][y])
     end
   end
-  print("Altitude", "Min:", min, "Max:", max)
+  map.altitude.min = simplex_map.min(map.altitude)
+  map.altitude.max = simplex_map.max(map.altitude)
 
-  -- TEMP hacked in copy to fix the issue so I can make sure everything is correct aaa
-  local function min(t)
-    local r = t[1][1]
-    for i=1,#t do
-      for j=1,#t[1] do
-        if r > t[i][j] then r = t[i][j] end
-      end
-    end
-    return r
+  local biome_order = {}
+  for order in pairs(biomes) do
+    biome_order[#biome_order + 1] = order
   end
-  local function max(t)
-    local r = t[1][1]
-    for i=1,#t do
-      for j=1,#t[1] do
-        if r < t[i][j] then r = t[i][j] end
-      end
-    end
-    return r
-  end
-  local function normalize(map, new_min, new_max)
-    local minimum = min(map)
-    local initialRange = max(map) - minimum
-    local finalRange = new_max - new_min
-    for i = 1, #map do
-      for j = 1, #map[1] do
-        map[i][j] = (map[i][j] - minimum) / initialRange * finalRange + new_min
-      end
-    end
-    map.min = min(map)
-    map.max = max(map)
-    return map -- superfluous
-  end
-  normalize(map.altitude, 0, 1)
+  table.sort(biome_order)
 
-  map.terrain = {}
+  local radius_squared = (map.size / 2)^2
+  map.biome = {}
   for x = 1, map.size do
-    map.terrain[x] = {}
+    map.biome[x] = {}
     for y = 1, map.size do
-      local value = map.altitude[x][y]
-      map.terrain[x][y] = {value, value, value, 1}
+      if lume.distance(x, y, map.size / 2, map.size / 2, true) < radius_squared then
+        local altitude = map.altitude[x][y]
+        local temperature = map.temperature[x][y]
+        local rainfall = map.rainfall[x][y]
+
+        -- modify temperature based on altitude
+        if altitude > 0 then
+          temperature = temperature - 0.0065 * altitude  -- -6.5 C / km
+        else
+          temperature = temperature + altitude / 1000 -- -1 C / km (deep water adjustment)
+        end
+        -- modify temperature by latitude
+        local polar_distance = math.abs(y - (map.size / 2))^1.1 -- experimenting with slight non-linearity
+        local max_temperature_delta = 40
+        temperature = temperature - (polar_distance / map.size * 2 * max_temperature_delta)
+        -- 'save' temperature changes
+        map.temperature[x][y] = temperature
+
+        -- choose biome
+        for _, order in ipairs(biome_order) do
+          local biome = biomes[order]
+          if altitude >= biome.altitude.min and altitude <= biome.altitude.max then
+            if temperature >= biome.temperature.min and temperature <= biome.temperature.max then
+              if rainfall >= biome.rainfall.min and rainfall <= biome.rainfall.max then
+                map.biome[x][y] = biome.color
+                break
+              end
+            end
+          end
+        end
+      else
+        -- clear non-planet zones
+        map.altitude[x][y] = nil
+        map.temperature[x][y] = nil
+        map.rainfall[x][y] = nil
+      end
     end
   end
 
-  -- NOTE this is missing the radius modifier, so it's a square map
-
   return map
 end