Update details.txt

Reflect changes and explain more.

README.md

@@ -1,7 +1,5 @@
 Minetest mod: droplift
 
-                ** May 1 -- Major changes -- Update strongly recommended **
-
 ==== Droplift ====
 
 Droplift lifts drops out of solid blocks.

details.txt

@@ -1,5 +1,5 @@
 Upon burial, drops may escape to one of the 26 surrounding nodes if any are non-obstructing ('walkable'==false).
-If the nearest player is within 8.5 nodes (by taxicab metric), spaces closer to that player are preferred, otherwise they are prioritised by +x, +y, +z.
+Spaces closest to the nearest player are preferred.
 
 If no such spaces are found, the drop is "entombed," and remains subject to lift physics until free of obstructing nodes.
 Lift physics holds a drop for one second before moving it upwards by one node every step, and does not seek other escape routes.
@@ -7,9 +7,9 @@ Lift physics holds a drop for one second before moving it upwards by one node ev
 Droplift does not distinguish between differently shaped node boxes, only what their 'walkable' setting is.
 This makes it easy to manually entomb drops using simple node types like slabs and glass panes.
 
-Entombed/free status is preserved across game reloads rather than retested. For example, a drop resting on a slab will remain at rest.
+Entombed/free status is preserved across game reloads rather than retested. For example, a drop resting on a slab will remain at rest, although technically inside an obstructing node.
 
-All drop velocities are zeroed on reload. This prevents buried drops from being sunk below their current floor.
+ALL drop velocities are zeroed on reload. This prevents resting-buried drops from burrowing below their current floor as they do in the default game. This only affects mods, as it's not possible to manually produce this condition under droplift.
 
 	-------
 	* API *
@@ -35,9 +35,11 @@ sync in [ false | 0 | seconds ]:
 
 I.e. a lift must occur AFTER the call and BEFORE the target time so it can schedule its NEXT lift to occur at that time, otherwise the sync request is ignored. The initial standing period before the first lift cannot be modified.
 
-Drops remain "entombed" while there is an outstanding sync time, regardless of whether they are actually buried, but will only receive calls while buried.
+Drops remain "entombed" while there is an outstanding sync time, regardless of whether they are actually buried, but will only receive calls while buried. Lift will always exit on unburied drops, and a scheduled lift cannot be delayed by additional sync setting.
 
-Sync info is not preserved across reloads.
+Sync info is not preserved across reloads. Timing is approximate and variable.
+
+Remember: Sync is primarily aesthetic, to ensure mod interactions display their activity nicely. Don't expect trickier uses to work perfectly.
 
 ----
 To disable lift physics on a drop, use:

init.lua

@@ -21,17 +21,6 @@ droplift = {
 
 --------------------------------------------------- Local
 
--- minetest.get_us_time is not defined in 0.4.10
-local seconds = 0.0
-if not minetest.get_us_time then
-	minetest.register_globalstep(function(dtime)
-				seconds = seconds + dtime
-			end)
-	minetest.get_us_time = function()
-		return seconds * 1000000
-	end
-end
-
 local function obstructed(p)
 	local n = minetest.get_node_or_nil(p)
 	return n and minetest.registered_nodes[n.name].walkable
@@ -40,64 +29,32 @@ end
 
 -- * Local escape *
 
-local function near_player(dpos)
-	local near = 8.5
-	local pp, d, ppos
-	for _,player in ipairs(minetest.get_connected_players()) do
-		pp = player:getpos()
-		pp.y = pp.y + 1
-		d = math.abs(pp.x-dpos.x) + math.abs(pp.y-dpos.y) + math.abs(pp.z-dpos.z)
-		if d < near then
-			near = d
-			ppos = pp
-		end
-	end
-	return ( near < 8.5 and ppos )
-end
-
-local function usign(r)
-	return ( r < 0 and -1 ) or 1
+local dist = function(p1,p2)
+	return (  (p1.y - p2.y)^2
+			+ (p1.x - p2.x)^2
+			+ (p1.z - p2.z)^2 )^0.5
 end
 
 local function escape(ent,pos)
-	local bias = {x = 1, y = 1, z = 1}
-	local o = {a="x", b="y", c="z"}
-	local pref = near_player(pos)
-	if pref then
-		bias = {x = usign(pref.x - pos.x), y = usign(pref.y - pos.y), z = usign(pref.z - pos.z)}
-		local mag={x = math.abs(pref.x - pos.x), y = math.abs(pref.y - pos.y), z = math.abs(pref.z - pos.z)}
-		if mag.z > mag.y then
-			if mag.y > mag.x then
-				o={a="z",b="y",c="x"}
-			elseif mag.z > mag.x then
-				o={a="z",b="x",c="y"}
-			else
-				o={a="x",b="z",c="y"}
-			end
-		else
-			if mag.z > mag.x then
-				o={a="y",b="z",c="x"}
-			elseif mag.y > mag.x then
-				o={a="y",b="x",c="z"}
-			end
-		end
+	local q, p, ep, d, dd = pos
+	for _,player in ipairs(minetest.get_connected_players()) do
+		p = player:getpos(); p.y = p.y + 1
+		d = dist(p,pos)
+		if not dd or (d < dd) then dd, q = d, {x=p.x,y=p.y,z=p.z} end
 	end
-
-	local p
-	for a = pos[o.a] + bias[o.a], pos[o.a] - bias[o.a], -bias[o.a] do
-		for b = pos[o.b] + bias[o.b], pos[o.b] - bias[o.b], -bias[o.b] do
-			for c = pos[o.c] + bias[o.c], pos[o.c] - bias[o.c], -bias[o.c] do
-				p = {[o.a]=a, [o.b]=b, [o.c]=c}
+	for x = pos.x - 1, pos.x + 1 do
+		p.x = x; for y = pos.y - 1, pos.y + 1 do
+			p.y = y; for z = pos.z - 1, pos.z + 1 do
+				p.z = z
 				if not obstructed(p) then
-					ent.object:setacceleration({x=0,y=-10,z=0})
-					ent.object:setpos(p)
-					return p
+					d = dist(q,p)
+					if not ep or (d < dd) then dd, ep = d, {x=p.x,y=p.y,z=p.z} end
 				end
 			end
 		end
 	end
-
-	return false
+	if ep then ent.object:setpos(ep) end
+	return ep
 end
 
 
@@ -114,35 +71,30 @@ local function lift(obj)
 			local t = 1
 			local s1 = ent.sync1
 			if s1 then
-				local sd = ent.sync0+s1-minetest.get_us_time()
-				if sd > 0 then t = sd/1000000 end
+				local sd = ent.sync0+s1-os.time()
+				if sd > 0 then t = sd end
 				ent.sync0, ent.sync1 = nil, nil
 			end
 -- Space
 			p = {x = p.x, y = math.floor(p.y - 0.5) + 1.800001, z = p.z}
 			obj:setpos(p)
 			if s1 or obstructed(p) then
-				obj:setvelocity({x = 0, y = 0, z = 0})
-				obj:setacceleration({x = 0, y = 0, z = 0})
 				minetest.after(t, lift, obj)
 				return
 			end
-		end -- if w
+		end
 -- Void.
 		ent.is_entombed, ent.sync0, ent.sync1 = nil, nil, nil
-	end  -- if p
+	end
 end
 
 -- ---------------- ASYNC
 
-local counter = function()
-	local k = 0
-	return function()
-				k = (k==9973 and 1) or k+1
-				return k
-			end
+local k = 0
+local function newhash()
+	k = (k==32767 and 1) or k+1
+	return k
 end
-local newhash = counter()
 
 local function async(obj, usync)
 	local p = obj:getpos()
@@ -157,29 +109,26 @@ local function async(obj, usync)
 					ent.hash = nil
 				end
 			elseif usync > 0 then
-				ent.sync0 = minetest.get_us_time()
+				ent.sync0 = os.time()
 				ent.sync1 = usync
 			end
 -- Space.
 			if hash == ent.hash then
 				obj:setpos({x = p.x, y = math.floor(p.y - 0.5) + 0.800001, z = p.z})
-				obj:setvelocity({x = 0, y = 0, z = 0})
-				obj:setacceleration({x = 0, y = 0, z = 0})
 				if not ent.is_entombed then
 					ent.is_entombed = true
 					minetest.after(1, lift, obj)
 				end
 			end
-		end -- if w
+		end
 		if hash == ent.hash then ent.hash = nil end
-	end  -- if p
+	end
 end
 
 droplift.invoke = function(obj, sync)
-	async(obj, (sync and math.max(0,sync)*1000000))
+	async(obj, (sync and math.max(0,sync)))
 end
 
-
 -- * Events *
 
 local function append_to_core_defns()
@@ -192,10 +141,11 @@ local function append_to_core_defns()
 		if staticdata ~= "" then 
 			if minetest.deserialize(staticdata).is_entombed then
 				ent.is_entombed = true
+				ent.object:setacceleration({x = 0, y = 0, z = 0})  -- Prevents 0.18m reload slippage. Not critical.
 				minetest.after(0.1, lift, ent.object)
 			end
 		end
-		ent.object:setvelocity({x = 0, y = 0, z = 0})
+		ent.object:setvelocity({x = 0, y = 0, z = 0})  -- Prevents resting-buried drops burrowing. 
 	end
 
 	-- Preserve state across reloads