Geodes as test for place by function

mods/MAPGEN/mcl_geodes/init.lua

@@ -0,0 +1,75 @@
+local adjacents = {
+	vector.new(1,0,0),
+	vector.new(-1,0,0),
+	vector.new(0,0,1),
+	vector.new(0,0,-1),
+	vector.new(0,1,0),
+	vector.new(0,-1,0)
+}
+
+local function makegeode(pos,pr)
+	local size = pr:next(3,18)
+	local p1 = vector.offset(pos,-size,-size,-size)
+	local p2 = vector.offset(pos,size,size,size)
+	local nn = minetest.find_nodes_in_area(p1,p2,{"group:material_stone"})
+	table.sort(nn,function(a, b)
+		   return vector.distance(pos, a) < vector.distance(pos, b)
+	end)
+	if not nn[1] then return end
+	for i=1,math.random(#nn) do
+		minetest.set_node(nn[i],{name="mcl_amethyst:amethyst_block"})
+	end
+	local nnn = minetest.find_nodes_in_area(p1,p2,{"mcl_amethyst:amethyst_block"})
+	for k,v in pairs(nnn) do
+		local all_amethyst = true
+		for kk,vv in pairs(adjacents) do
+			local pp = vector.add(v,vv)
+			local an = minetest.get_node(pp)
+			if an.name ~= "mcl_amethyst:amethyst_block" then
+				if minetest.get_item_group(an.name,"material_stone") > 0 then
+					minetest.set_node(pp,{name="mcl_amethyst:calcite"})
+					if pr:next(1,5) == 1 then
+						minetest.set_node(v,{name="mcl_amethyst:budding_amethyst_block"})
+					end
+					all_amethyst = false
+				elseif an.name ~= "mcl_amethyst:amethyst_block" and an.name ~= "air" then
+					all_amethyst = false
+				end
+			end
+		end
+		if all_amethyst then minetest.set_node(v,{name="air"}) end
+	end
+
+	local nnnn = minetest.find_nodes_in_area_under_air(p1,p2,{"mcl_amethyst:amethyst_block"})
+	for k,v in pairs(nnnn) do
+		local r = pr:next(1,50)
+		if r < 10 then
+			minetest.set_node(vector.offset(v,0,1,0),{name="mcl_amethyst:amethyst_cluster",param2=1})
+		end
+	end
+end
+
+mcl_structures.register_structure("geodes",{
+	place_on = {"mcl_core:stone"},
+	spawn_by = {"air"},
+	num_spawn_by = 2,
+	fill_ratio = 0.002,
+	flags = "place_center_x, place_center_z, force_placement",
+	biomes = ocean_biomes,
+	y_max = mcl_vars.mg_overworld_max,
+	y_min = mcl_vars.mg_overworld_min,
+	filenames = schems,
+	y_offset = function(pr) return pr:next(-4,-2) end,
+	place_func = function(pos,def,pr)
+		local p = vector.new(pos.x + pr:next(-30,30),pos.y,pos.z + pr:next(-30,30))
+		makegeode(pos,pr)
+	end,
+})
+
+minetest.register_chatcommand("makegeode",{
+	privs = { debug = true },
+	func=function(n,p)
+		local pos = pl:get_pos()
+		makegeode(pos,PseudoRandom(minetest.get_mapgen_setting("seed")))
+	end
+})

mods/MAPGEN/mcl_geodes/mod.conf

@@ -0,0 +1,3 @@
+name = mcl_geodes
+author = cora
+depends = mcl_init, mcl_structures

mods/MAPGEN/mcl_structures/api.lua

@@ -2,7 +2,7 @@ local registered_structures = {}
 
 --[[] structure def:
 {
-	fill_ratio= OR noise = {} 
+	fill_ratio = OR noise = {}
 	biomes =
 	y_min =
 	y_max =
@@ -28,8 +28,8 @@ local function place_schem(pos, def, pr)
 		local file = def.filenames[pr:next(1,#def.filenames)]
 		local pp = vector.offset(pos,0,y_offset,0)
 		mcl_structures.place_schematic(pp, file, "random", nil, true, "place_center_x,place_center_z",def.after_place,pr,{pos,def})
-	elseif def.place_func and def.place_func(pos,def) then
-		def.after_place(pos,def)
+	elseif def.place_func and def.place_func(pos,def,pr) then
+		def.after_place(pos,def,pr)
 	end
 end