From 6f129926ad52abc7210f1a422b167f671eedd3c9 Mon Sep 17 00:00:00 2001
From: Eric <leucome@hotmail.com>
Date: Tue, 24 Sep 2019 16:16:24 -0400
Subject: [PATCH] Memory cache + Biome API

Keep few map in memory for the mapgen to work with. Once discarded the Biome API is used instead.

Map generation is even faster this way and it do not require the use of a files on the drive.
---
 init.lua | 50 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/init.lua b/init.lua
index 4b64fa2..ef9eb19 100644
--- a/init.lua
+++ b/init.lua
@@ -11,8 +11,8 @@
 
 ]]--
 
-local wp = minetest.get_worldpath() .. "/luscious"
-minetest.mkdir(wp)
+gt = {}
+tablesize = 0
 
 local mgp = minetest.get_mapgen_params()
 local chunksize = 16 * mgp.chunksize
@@ -28,25 +28,33 @@ local function cmpy(p2, y)
 		return math.max(1, p2)
 	end
 end
+
+local function chose_color(pos)
+	-- Calculate color from biome heat and humidity.
+	local biome_data = minetest.get_biome_data(pos)
+	local hum1 = biome_data.humidity
+	local temp1 = biome_data.heat 
+	local vh = math.floor(math.min(math.max(math.floor(hum1), 0), 100) / 6.6)
+	local vt = math.floor(math.min(math.max(math.floor(temp1), 0), 100) / 6.6)
+	vt = vt - math.max(math.min(vt, math.floor(pos.y / 16)), 0)
+	return vh * 16 + vt
+end
+
 local function on_construct(pos)
 	-- get chunk from pos
 	local v = vector.apply(pos, function(a) return math.floor((a - 48) / chunksize) end)
 	local o = vector.subtract(pos, vector.apply(v, function(a) return (a * chunksize) + 48 end))
 	local l = o.z * (chunksize) + o.x
 	local p = minetest.hash_node_position(v)
-
-	local f = io.open(wp .. "/" .. string.format("%d", p), "r")
-	if not f then
-		minetest.log("error", "unable to find map for " .. string.format("%d", p))
-		return
-	end
-
-	local z = f:read("*a")
-	f:close()
-	local map = minetest.decompress(z)
-
+	local map = gt[p]
+	local mv = 0
 	local node = minetest.get_node(pos)
-	node.param2 = cmpy(string.byte(map, l + 1), pos.y)
+	if map == nil then
+		mv = chose_color(pos) 
+	else
+		mv = cmpy(string.byte(map, l + 1), pos.y)
+	end
+	node.param2 = mv
 	minetest.swap_node(pos, node)
 end
 
@@ -146,12 +154,14 @@ minetest.register_on_generated(function(minp, maxp, blockseed)
 		h2 = math.floor(math.min(math.max(math.floor(h2), 0), 100) / 6.6)
 		map = map .. string.char(h1 + (h2 * 16))
 	end
-	local p = string.format("%d", minetest.hash_node_position(v))
-
-	local f = assert(io.open(wp .. "/" .. p, "w"), wp .. "/" .. p)
-	f:write(minetest.compress(map))
-	f:close()
-
+	local p = minetest.hash_node_position(v)
+	if tablesize > 75 then
+		gt = {}
+		collectgarbage()
+		tablesize = 0
+	end
+	tablesize = tablesize + 1
+	gt[p] = map
 	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
 	local area = VoxelArea:new{MinEdge = emin, MaxEdge = emax}
 	local data = vm:get_data()