write something there

mods/effervescence/effervescence_decorators/init.lua

@@ -0,0 +1,113 @@
+local strategy = {
+  -- decoration-based gennotify node selection strategy
+  gennotify = {
+    register = function(self, name, ddef)
+      ddef.name = name
+      effervescence.register_decorator({
+        name = name,
+        apply_to = function(self, npmap)
+          local nlist = {}
+          for node,particles in pairs(npmap) do
+            table.insert(nlist,node)
+            npmap[node] = table.concat(particles,",")
+          end
+          self.nodes = npmap
+
+          ddef.place_on = nlist
+          core.register_decoration(ddef)
+
+          self.did = core.get_decoration_id(name)
+          core.set_gen_notify({ decoration = true },{ self.did })
+          self.did = "decoration#" .. self.did
+        end,
+        decorate = function(self, minp, maxp, blockseed)
+          local gennotify = core.get_mapgen_object("gennotify")
+          local positions = gennotify[self.did] or {}
+          for _,pos in ipairs(positions) do
+            local node = core.get_node(pos).name
+            local particles = self.nodes[node]
+            if particles then
+              local meta = core.get_meta(pos)
+              meta:set_string("effervescence.particles",particles)
+            end
+          end
+        end,
+      })
+    end,
+  },
+
+  -- random sample node selection strategy
+  sample = {
+    generation_id = 0,
+    nodelist = { init = false },
+    init_decorate = function(self, blockseed)
+      if self.nodelist.init == false then
+        local nodelist = {}
+        for node,_ in pairs(self.nodelist) do
+          table.insert(nodelist,node)
+        end
+        self.nodelist = nodelist
+      end
+      if blockseed ~= self.generation_id then
+        self.generation_id = blockseed
+        local _, emin, emax = core.get_mapgen_object("voxelmanip")
+        self.nodes = core.find_nodes_in_area(emin,emax,self.nodelist,true)
+      end
+    end,
+    register = function(self, name, per)
+      local sampler = self
+      effervescence.register_decorator({
+        name = name,
+        apply_to = function(self, npmap)
+          self.nodes = npmap
+          for node,particles in pairs(npmap) do
+            npmap[node] = table.concat(particles,",")
+            sampler.nodelist[node] = true
+          end
+        end,
+        decorate = function(self, minp, maxp, blockseed)
+          sampler:init_decorate(blockseed)
+          for node,particles in pairs(self.nodes) do
+            local positions = sampler.nodes[node]
+            if positions then
+              local plen = #positions
+              local pcgr = PcgRandom(blockseed)
+              for i = 0, math.floor(plen / per), 1 do
+                local pos = positions[pcgr:next(1,plen)]
+                local meta = core.get_meta(pos)
+                meta:set_string("effervescence.particles",particles)
+              end
+            end
+          end
+        end,
+      })
+    end,
+  },
+}
+
+-- Register gennotify decorators
+strategy.gennotify:register("effervescence:floors",{
+  deco_type = "simple",
+  fill_ratio = 0.00375,
+  decoration = "air",
+  flags = "all_floors",
+})
+
+strategy.gennotify:register("effervescence:ceilings",{
+  deco_type = "simple",
+  fill_ratio = 0.00375,
+  decoration = "air",
+  flags = "all_ceilings",
+})
+
+strategy.gennotify:register("effervescence:liquid_surface",{
+  deco_type = "simple",
+  fill_ratio = 0.00425,
+  decoration = "air",
+  flags = "liquid_surface",
+})
+
+-- Register sample decorators
+strategy.sample:register("effervescence:many",10)
+strategy.sample:register("effervescence:few",50)
+strategy.sample:register("effervescence:rare",250)

mods/effervescence/effervescence_decorators/mod.conf

@@ -0,0 +1,5 @@
+name = effervescence_decorators
+title = Effervescence Builtin Decorators
+description = Adds useful decorators for Effervescence
+author = EmptyStar
+depends = effervescence