mods/ENTITIES/mcl_item_entity/init.lua

@@ -27,6 +27,8 @@ local mcl_item_entity = {}
 local item_drop_settings                 = {} --settings table
 item_drop_settings.dug_buffer            = 0.65 -- the warm up period before a dug item can be collected
 item_drop_settings.age                   = 1.0 --how old a dropped item (_insta_collect==false) has to be before collecting
+item_drop_settings.fluid_flow_rate       = 1.39 --the speed of a flowing fluid, used when computing push and drag forces of water on items; default is tuned to Minecraft
+item_drop_settings.fluid_drag            = 0.8 --how much drag water has on items (how quickly an item's motion will settle onto the water's flow speed)
 item_drop_settings.radius_magnet         = 2.0 --radius of item magnet. MUST BE LARGER THAN radius_collect!
 item_drop_settings.xp_radius_magnet      = 7.25 --radius of xp magnet. MUST BE LARGER THAN radius_collect!
 item_drop_settings.radius_collect        = 0.2 --radius of collection
@@ -778,11 +780,26 @@ minetest.register_entity(":__builtin:item", {
 			-- Just to make sure we don't manipulate the speed for no reason
 			if vec.x ~= 0 or vec.y ~= 0 or vec.z ~= 0 then
 				-- Minecraft Wiki: Flowing speed is "about 1.39 meters per second"
-				local f = 1.39
-				-- Set new item moving speed into the direciton of the liquid
-				local newv = vector.multiply(vec, f)
+				local f = item_drop_settings.fluid_flow_rate --1.39
+
+				-- Apply the force of the flowing liquid onto the item's velocity
+				local newv = vector.multiply(vec, f) 
 				self.object:set_acceleration({x = 0, y = 0, z = 0})
-				self.object:set_velocity({x = newv.x, y = -0.22, z = newv.z})
+
+				local oldvel = self.object:get_velocity() -- v is vector, vel is velocity
+
+				-- drag
+                newv.x = newv.x - (oldvel.x - newv.x) * item_drop_settings.fluid_drag
+                newv.y = newv.y - (oldvel.y - newv.y) * item_drop_settings.fluid_drag
+                newv.z = newv.z - (oldvel.z - newv.z) * item_drop_settings.fluid_drag
+
+                newv.y = newv.y + -0.22 -- (keep slight downward thrust from previous version of code)
+                                        -- NOTE:    is there any particular reason we have this, anyway?
+                                        --          since fluid drag is now on, we could as well just
+                                        --          apply gravity here; drag will slow down the fall
+                                        --          realistically
+				
+				self.object:set_velocity({x = oldvel.x + newv.x, y = oldvel.y + newv.y, z = oldvel.z + newv.z})
 
 				self.physical_state = true
 				self._flowing = true