From 9db4f7af6aebd6e902e578d0486d436f79fdec52 Mon Sep 17 00:00:00 2001
From: Izzy <yzziizzy@gmail.com>
Date: Sun, 2 Jun 2019 12:43:56 -0600
Subject: [PATCH] big nasty function to find flat areas

---
 behaviors/area_stats.lua | 190 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 190 insertions(+)
 create mode 100644 behaviors/area_stats.lua

diff --git a/behaviors/area_stats.lua b/behaviors/area_stats.lua
new file mode 100644
index 0000000..d2ddead
--- /dev/null
+++ b/behaviors/area_stats.lua
@@ -0,0 +1,190 @@
+
+
+
+
+local type_lookup = {}
+
+for name,def in pairs(minetest.registered_nodes) do
+	if def.groups.soil then
+		type_lookup[minetest.get_content_id(name)] = 1 -- 1 is "ground"
+	elseif def.groups.cracky then
+		type_lookup[minetest.get_content_id(name)] = 1 -- cracky things are part of the ground
+	elseif def.groups.sand then
+		type_lookup[minetest.get_content_id(name)] = 1 
+	elseif def.groups.crumbly then
+		type_lookup[minetest.get_content_id(name)] = 1 -- gravel, clay, snow, etc
+		
+	elseif def.groups.choppy then
+		type_lookup[minetest.get_content_id(name)] = 0 -- trees, wood, etc
+	elseif def.groups.snappy then
+		type_lookup[minetest.get_content_id(name)] = 0 -- grass, leaves, etc
+	elseif def.groups.fleshy then
+		type_lookup[minetest.get_content_id(name)] = 0 -- apples
+	elseif def.groups.liquid then
+		type_lookup[minetest.get_content_id(name)] = 0 -- water, lava
+	end
+	
+end
+
+type_lookup[minetest.get_content_id("air")] = 0
+
+
+
+
+
+bt.register_action("AreaIsFlat", {
+	tick = function(node, data)
+		if not data.targetPos then 
+			return "failed" 
+		end
+		data.targetPos = vector.floor(data.targetPos)
+		
+		local mmin = vector.add(node.min, data.targetPos) 
+		local mmax = vector.add(node.max, data.targetPos) 
+
+-- 		local x1 = node.max.x + data.targetPos.x
+-- 		local y1 = node.max.y + data.targetPos.y
+-- 		local z1 = node.max.z + data.targetPos.z
+-- 		local x0 = node.min.x + data.targetPos.x
+-- 		local y0 = node.min.y + data.targetPos.y
+-- 		local z0 = node.min.z + data.targetPos.z
+		
+		local vm = minetest.get_voxel_manip()
+		local emin, emax = vm:read_from_map(
+			mmin, 
+			mmax 
+		)
+		local area = VoxelArea:new{MinEdge=emin, MaxEdge=emax}
+		local data = vm:get_data()
+		print(dump(emin))
+		print(dump(emax))
+		
+		local x1 = mmax.x -- node.min.x
+		local y1 = mmax.y -- node.min.y
+		local z1 = mmax.z -- node.min.z
+		local x0 = mmin.x
+		local y0 = mmin.y
+		local z0 = mmin.z
+		
+		function ind(x, y, z)
+			local i = (z * area.zstride) + (y * area.ystride) + x + 1
+			return math.floor(i)
+		end
+		
+		
+		local deltas = {}
+		local last_y = (y1 + y0) / 2
+		local total_found = 0
+		local mean = 0
+		local total_missing = 0
+-- 		print(x1 .. " " .. y1 .. " " ..z1 )
+		for z = z0, z1 do -- for each xy plane progressing northwards
+			for x = x0, x1 do -- for each node do
+				
+				local y = math.floor(y1 / 2)
+				local vi = area:index(x, y, z)
+				
+				
+				local t = type_lookup[data[vi]] or 0
+-- 				print(t .. " d:" .. data[vi].. " - x: " .. x .. ", y: " .. y .. ", z: " ..z) 
+				
+				local found = false
+				if t == 0 then -- in the air, go down
+					while y > y0 do
+						y = y - 1
+						vi = area:index(x, y, z)
+						t = type_lookup[data[vi]] or 0
+-- 					print("too high "..y)
+-- 						print(t .. " d:" .. data[vi].. " - x: " .. x .. ", y: " .. y .. ", z: " ..z) 
+						
+						
+						if t == 1 then
+							-- found the ground
+-- 							print(minetest.get_name_from_content_id(data[vi]))
+							found = true
+							break
+						else 
+-- 						print(minetest.get_name_from_content_id(data[vi]))
+						end
+					end
+				
+ 				else -- underground, go up
+					
+					while y < y1 do
+						y = y + 1
+						vi = area:index(x, y, z)
+-- 					print("too low " .. y)
+						t = type_lookup[data[vi] ] or 0
+-- 						print(t .. " d:" .. data[vi].. " - x: " .. x .. ", y: " .. y .. ", z: " ..z) 
+-- 						print(
+						if t == 0 then
+							-- found the sky, go back down one
+							y = y - 1
+							vi = area:index(x, y, z)
+-- 							print(minetest.get_name_from_content_id(data[vi]))
+							found = true
+							break
+						else 
+-- 						print(minetest.get_name_from_content_id(data[vi]))
+						end
+					end
+				
+				end
+				
+				if found then
+				vi = area:index(x, y, z)
+-- 				print("----- found " .. data[vi] .. " " ..minetest.get_name_from_content_id(data[vi]))
+					last_y = y
+					local dy = y - y0 
+					deltas[dy] = (deltas[dy] or 0) + 1
+					total_found = total_found + 1
+					mean = mean + dy
+				else
+					total_missing = total_missing + 1
+-- 				print("--------- missing")
+				end
+				
+			end
+		end
+		
+		print("total_found ".. total_found)
+		print("total_missing ".. total_missing)
+		print(dump(deltas))
+		mean = mean / total_found
+		
+		local variance = 0
+		for k,v in pairs(deltas) do
+			local d = mean - k
+			variance = variance + (d * d)
+		end
+		
+		variance = variance / total_found
+		
+		print("variance: ".. variance)
+		if variance > node.max_variance then
+			return "failed"
+		end
+		
+		return "success"
+	end,
+	
+	ctor = function(min, max, max_variance)
+		return {
+			min = min,
+			max = max,
+			max_variance = max_variance,
+		}
+	end,
+})
+
+
+
+
+
+
+
+
+
+
+
+