add optimization for stacks

src/main.lua

@@ -369,6 +369,17 @@ local function directiondist(direction, wanted)
     if direction ~= wanted then return 1 end -- failsafes
     if direction == wanted then return 0 end
 end
+local function needstobeplaced(placecode, clayer)
+    if clayer == 0 or clayer == 2 then
+        return placecode == 1
+    end
+    if clayer == 1 then
+        return placecode == 1 or placecode == 4
+    end
+    if clayer == 3 then
+        return placecode == 1 or placecode == 4 or placecode == 3
+    end
+end
 local function getnearestunplaced(buf, pbuf, cx,cy,cz,clayer, sx,sz, direction)
     local distance = math.huge
     local selected = nil
@@ -388,15 +399,7 @@ local function getnearestunplaced(buf, pbuf, cx,cy,cz,clayer, sx,sz, direction)
 
             local needplace = buf[posasstring(x,cy,y)]
             if pbuf[posasstring(x,cy,y)] then needplace = 0 end -- already placed
-            if clayer == 0 or clayer == 2 then
-                needplace = needplace == 1
-            end
-            if clayer == 1 then
-                needplace = needplace == 1 or needplace == 4
-            end
-            if clayer == 3 then
-                needplace = needplace == 1 or needplace == 4 or needplace == 3
-            end
+            needplace = needstobeplaced(needplace, clayer)
             if needplace then -- needs to be placed, calculate distance
                 local cd = math.abs(y-cz)+math.abs(x-cx) -- raw distance (amount of blocks between)
                 cd = cd + extracost
@@ -545,6 +548,107 @@ local function printdes(buf, dimensions)
     center(direction)
 end
 
+-- vertical stack printing
+local function VP_optimizestack(target)
+    -- go from top to bottom and erase false entries until we encounter a true one.
+    local index = #target
+    while #target > 0 do
+        if target[index] then break else
+            table.remove(target, index)
+            index = index - 1
+        end
+    end
+
+    return target
+end
+local function VP_createstack(buf, dimensions)
+    local fout = {
+        ["height"] = dimensions["y"]*(4)+1,
+        ["dimensions"] = dimensions,
+    }
+    local out = {}
+
+
+    for x=1,dimensions["x"],1 do
+        for z=1,dimensions["z"],1 do
+
+            local tempbuf = {}
+            for y=1,dimensions["y"],1 do -- for each y dimension
+                local placecode = buf[posasstring(x,y,z)]
+                for layer=1,3,1 do -- layers
+                    table.insert(tempbuf, needstobeplaced(placecode, layer))
+                end
+                -- ceiling
+                table.insert(tempbuf, buf[posasstring(_cx,cy,_cz)] ~= 2)
+            end
+            VP_optimizestack(tempbuf)
+
+            if #tempbuf > 0 then out[posasstring(x,z)] = tempbuf end
+        end
+    end
+
+    fout["stacks"] = out
+    return fout
+end
+local function VP_splitstack(_stack, x)
+    local stack = _stack["stacks"]
+    local dimensions = _stack["dimensions"]
+    local sx = dimensions["sx"]
+    local sz = dimensions["sz"]
+    local height = _stack["height"]
+    local stacks = {}
+    local unevenstack = {}
+    local stackmod = math.fmod(#stack, x)
+    local stackdiv = math.floor(#stack/x)
+
+    if stackmod ~= 0 then
+        for tempstackindex=0,stackmod,1 do
+            table.insert(unevenstack, stack[posasstring(math.fmod(tempstackindex, sx),math.floor(tempstackindex/sx))])
+        end
+    end
+
+    if stackdiv ~= 0 then
+        local eind = 0
+        local x2 = x
+        if stackmod ~= 0 then x2 = x - 1 end
+        for _=0,x2,1 do
+            local buf = {}
+            for stackind=eind,stackdiv+eind,1 do
+                table.insert(buf, stack[posasstring(math.fmod(stackind, sx),math.floor(stackind/sx))])
+            end
+            table.insert(stacks, buf)
+            eind = eind + stackdiv
+        end
+    end
+
+    local out = {}
+    if #unevenstack > 0 then table.insert(out,unevenstack) end
+    for _,v in pairs(stacks) do
+        table.insert(out,v)
+    end
+    return out
+end
+--[[local function VP_inspectsplitted(stacks, dimensions) -- I will probably never finish this.
+    local currentselected = 1
+
+    while true do
+        reset() -- render
+        local _,y = term.getSize()
+        term.setCursorPos(1,y)
+        term.setcol(colors.yellow, colors.black)
+        term.write("Currentlayer: ")
+        term.write(tostring(currentselected))
+
+        local event = table.pack(os.pullEvent())
+        if event[1] == "key" then
+            
+        end
+    end
+end]]
+local function VP_printstack(buf, dimensions)
+
+end
+
 while true do
     integritycheck()
     local action = selopt({