Add cactus generation, desert_sand and desert_stone

mods/default/init.lua

@@ -698,6 +698,16 @@ minetest.register_node("default:stone", {
 	sounds = default.node_sound_stone_defaults(),
 })
 
+minetest.register_node("default:desert_stone", {
+	description = "Desert stone",
+	tile_images = {"default_desert_stone.png"},
+	is_ground_content = true,
+	groups = {cracky=3},
+	drop = 'default:cobble',
+	legacy_mineral = true,
+	sounds = default.node_sound_stone_defaults(),
+})
+
 minetest.register_node("default:stone_with_coal", {
 	description = "Stone with coal",
 	tile_images = {"default_stone.png^default_mineral_coal.png"},
@@ -754,6 +764,14 @@ minetest.register_node("default:sand", {
 	sounds = default.node_sound_sand_defaults(),
 })
 
+minetest.register_node("default:desert_sand", {
+	description = "Desert sand",
+	tile_images = {"default_desert_sand.png"},
+	is_ground_content = true,
+	groups = {sand=1, crumbly=3},
+	sounds = default.node_sound_sand_defaults(),
+})
+
 minetest.register_node("default:gravel", {
 	description = "Gravel",
 	tile_images = {"default_gravel.png"},
@@ -1356,6 +1374,7 @@ end
 
 default.register_falling_node("default:sand", "default_sand.png")
 default.register_falling_node("default:gravel", "default_gravel.png")
+default.register_falling_node("default:desert_sand", "default_desert_sand.png")
 
 --
 -- Global callbacks

mods/default/mapgen.lua

@@ -22,6 +22,8 @@ minetest.register_alias("mapgen_junglegrass", "default:junglegrass")
 minetest.register_alias("mapgen_stone_with_coal", "default:stone_with_coal")
 minetest.register_alias("mapgen_stone_with_iron", "default:stone_with_iron")
 minetest.register_alias("mapgen_mese", "default:mese")
+minetest.register_alias("mapgen_desert_sand", "default:desert_sand")
+minetest.register_alias("mapgen_desert_stone", "default:desert_stone")
 
 --
 -- Ore generation
@@ -68,13 +70,20 @@ local function generate_ore(name, wherein, minp, maxp, seed, chunks_per_volume,
 	--print("generate_ore done")
 end
 
-local function make_papyrus(pos, size)
+function default.make_papyrus(pos, size)
 	for y=0,size-1 do
 		local p = {x=pos.x, y=pos.y+y, z=pos.z}
 		minetest.env:set_node(p, {name="default:papyrus"})
 	end
 end
 
+function default.make_cactus(pos, size)
+	for y=0,size-1 do
+		local p = {x=pos.x, y=pos.y+y, z=pos.z}
+		minetest.env:set_node(p, {name="default:cactus"})
+	end
+end
+
 minetest.register_on_generated(function(minp, maxp, seed)
 	generate_ore("default:stone_with_coal", "default:stone", minp, maxp, seed,   1/8/8/8,    5, -31000,  64)
 	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+1, 1/16/16/16, 5,   -5,   7)
@@ -136,7 +145,40 @@ minetest.register_on_generated(function(minp, maxp, seed)
 				local z = pr:next(z0, z1)
 				if minetest.env:get_node({x=x,y=1,z=z}).name == "default:dirt_with_grass" and
 						minetest.env:find_node_near({x=x,y=1,z=z}, 1, "default:water_source") then
-					make_papyrus({x=x,y=2,z=z}, pr:next(2, 4))
+					default.make_papyrus({x=x,y=2,z=z}, pr:next(2, 4))
+				end
+			end
+		end
+		end
+		-- Generate cactuses
+		local perlin1 = minetest.env:get_perlin(230, 3, 0.7, 100)
+		-- Assume X and Z lengths are equal
+		local divlen = 8
+		local divs = (maxp.x-minp.x)/divlen+1;
+		for divx=0,divs-1 do
+		for divz=0,divs-1 do
+			local x0 = minp.x + math.floor((divx+0)*divlen)
+			local z0 = minp.z + math.floor((divz+0)*divlen)
+			local x1 = minp.x + math.floor((divx+1)*divlen)
+			local z1 = minp.z + math.floor((divz+1)*divlen)
+			-- Determine cactus amount from perlin noise
+			local cactus_amount = math.floor(perlin1:get2d({x=x0, y=z0}) * 6 - 5)
+			-- Find random positions for cactus based on this random
+			local pr = PseudoRandom(seed+1)
+			for i=0,cactus_amount do
+				local x = pr:next(x0, x1)
+				local z = pr:next(z0, z1)
+				-- Find ground level (0...15)
+				local ground_y = nil
+				for y=30,0,-1 do
+					if minetest.env:get_node({x=x,y=y,z=z}).name ~= "air" then
+						ground_y = y
+						break
+					end
+				end
+				-- If desert sand, make cactus
+				if ground_y and minetest.env:get_node({x=x,y=ground_y,z=z}).name == "default:desert_sand" then
+					default.make_cactus({x=x,y=ground_y+1,z=z}, pr:next(3, 4))
 				end
 			end
 		end