realtest/mods/trees/init.lua

trees = {}

dofile(minetest.get_modpath("trees").."/leavesgen.lua")

function trees.make_tree(pos, tree)
	local tree = realtest.registered_trees[tree]
	if not table.contains(tree.grounds, minetest.env:get_node({x=pos.x,y=pos.y-1,z=pos.z}).name) then
		return
	end
	local height = tree.height()
	for i = 1,height do
		if minetest.env:get_node({x=pos.x, y=pos.y+i, z=pos.z}).name ~= "air" then
			return
		end
	end
	for i = 0,height do
		minetest.env:add_node({x=pos.x, y=pos.y+i, z=pos.z}, {name=tree.name.."_trunk"})
	end
	for i = 1,#tree.leaves do
		local p = {x=pos.x+tree.leaves[i][1], y=pos.y+height+tree.leaves[i][2], z=pos.z+tree.leaves[i][3]}
		if minetest.env:get_node(p).name == "air" or minetest.env:get_node(p).name == "ignore" then
			minetest.env:add_node(p, {name=tree.name.."_leaves"})
		end
	end
end

local function generate(tree, minp, maxp, seed, chunks_per_volume, ore_per_chunk, height_min, height_max)
	if maxp.y < height_min or minp.y > height_max then
		return
	end
	local y_min = math.max(minp.y, height_min)
	local y_max = math.min(maxp.y, height_max)
	local volume = (maxp.x-minp.x+1)*(y_max-y_min+1)*(maxp.z-minp.z+1)
	local pr = PseudoRandom(seed)
	local num_chunks = math.floor(chunks_per_volume * volume)
	local chunk_size = 3
	if ore_per_chunk <= 4 then
		chunk_size = 2
	end
	local inverse_chance = math.floor(chunk_size*chunk_size*chunk_size / ore_per_chunk)
	for i=1,num_chunks do
		local y0 = pr:next(y_min, y_max-chunk_size+1)
		if y0 >= height_min and y0 <= height_max then
			local x0 = pr:next(minp.x, maxp.x-chunk_size+1)
			local z0 = pr:next(minp.z, maxp.z-chunk_size+1)
			local p0 = {x=x0, y=y0, z=z0}
			for x1=0,chunk_size-1 do
				for y1=0,chunk_size-1 do
					for z1=0,chunk_size-1 do
						if pr:next(1,inverse_chance) == 1 then
							local x2 = x0+x1
							local y2 = y0+y1
							local z2 = z0+z1
							local p2 = {x=x2, y=y2, z=z2}
							local p3 = {x=x2, y=y2+1, z=z2}
							if minetest.env:get_node(p3).name == "air" and 
								not minetest.env:find_node_near(p3, realtest.registered_trees[tree].radius, "group:tree") then
								trees.make_tree(p3, tree)
							end
						end
					end
				end
			end
		end
	end
end

dofile(minetest.get_modpath("trees").."/registration.lua")

minetest.register_on_generated(function(minp, maxp, seed)
	local pr = PseudoRandom(seed)
	for key, value in pairs(realtest.registered_trees) do
		if pr:next(1, 10) == 1 then
			generate(key, minp, maxp, seed, 1/8/2, 1, -50, 100)
		end
	end
end)