preview generator

.luacheckrc

@@ -14,5 +14,5 @@ read_globals = {
 	"minetest",
 
 	-- mods
-	"mapblock_lib", "mtt", "Promise"
+	"mapblock_lib", "mtt", "Promise", "isogen"
 }

api.lua

@@ -29,6 +29,7 @@ function building_lib.register_building(name, def)
 		error("unexpected modname: '" .. parts[1] .. "' expected: " .. minetest.get_current_modname())
 	end
 
+	def.modname = parts[1]
 	buildings[name] = def
 end
 

init.lua

@@ -28,6 +28,11 @@ dofile(MP .. "/events.lua")
 dofile(MP .. "/hacks.lua")
 dofile(MP .. "/mapgen.lua")
 
+local ie = minetest.request_insecure_environment()
+if ie and minetest.get_modpath("isogen") then
+	loadfile(MP .. "/previewgen.lua")(ie)
+end
+
 if minetest.get_modpath("mtt") and mtt.enabled then
 	dofile(MP .. "/events.spec.lua")
 	dofile(MP .. "/conditions.spec.lua")

mod.conf

@@ -1,4 +1,4 @@
 name = building_lib
 description = Mapblock granular building placement and tools
 depends = mapblock_lib, promise, wield_events
-optional_depends = mtt
+optional_depends = mtt, isogen

previewgen.lua

@@ -0,0 +1,85 @@
+local ie = ...
+
+local function generate_preview(building_def)
+    local catalog
+    local offset = {x=0, y=0, z=0}
+    local size
+
+    if type(building_def.catalog) == "table" then
+        catalog = mapblock_lib.get_catalog(building_def.catalog.filename)
+        offset = building_def.catalog.offset or {x=0, y=0, z=0}
+        size = building_def.catalog.size or {x=1, y=1, z=1}
+    else
+        catalog = mapblock_lib.get_catalog(building_def.catalog)
+        size = catalog:get_size()
+    end
+
+    local mb_pos2 = vector.add(offset, vector.subtract(size, 1))
+
+    local min = mapblock_lib.get_mapblock_bounds_from_mapblock(offset)
+    local _, max = mapblock_lib.get_mapblock_bounds_from_mapblock(mb_pos2)
+
+    local png = isogen.draw(min, max, {
+        cube_len = 8,
+        get_node = function(pos)
+            return catalog:get_node(pos)
+        end
+    })
+
+    local filename = minetest.get_modpath(building_def.modname) ..
+        "/textures/" .. building_def.modname ..
+        "_preview_" .. building_def.name .. ".png"
+
+    local f = ie.io.open(filename, "wb")
+    if not f then
+        return false, "could not open file: '" .. filename .. "'"
+    end
+
+    f:write(png)
+    f:close()
+
+    return true
+end
+
+minetest.register_chatcommand("building_previewgen", {
+    params = "[modname]",
+    privs = {
+        mapblock_lib = true
+    },
+    func = function(name, modname)
+        local buildings = building_lib.get_buildings()
+        local list = {}
+        for _, building in pairs(buildings) do
+            if building.modname == modname and building.placement == "mapblock_lib" then
+                table.insert(list, building)
+            end
+        end
+
+        if #list == 0 then
+            return false, "no buildings found with given modname"
+        end
+
+        local worker
+        worker = function()
+            local building = table.remove(list)
+            if not building then
+                minetest.chat_send_player(name, "Done generating previews")
+                return
+            end
+
+            minetest.chat_send_player(name, "Generating preview for '" .. building.name .. "'")
+            local success, err = generate_preview(building)
+            if not success then
+                minetest.chat_send_player(
+                    name,
+                    "Preview generation failed for building: '" .. building.name .. "', error: " .. err
+                )
+            else
+                minetest.after(0, worker)
+            end
+        end
+
+        minetest.after(0, worker)
+        return true, "Scheduled " .. #list .. " buildings for preview-generation"
+    end
+})