Tweak mesecon control of forcefield

Drop support for negative mesecon control.  This requires users of
negative mesecon control to invert their mesecon signal externally.

Comment on rationale for the way toggle buttons in formspec are managed.

2 files changed, 12 insertions, 12 deletions

diff --git a/technic/locale/template.txt b/technic/locale/template.txt
index d771c09..43090df 100644
--- a/technic/locale/template.txt
+++ b/technic/locale/template.txt
@@ -56,8 +56,7 @@ Mode: %s =
 single items =
 whole stacks =
 Ignoring Mesecon Signal =
-Controlled by Positive Mesecon Signal =
-Controlled by Inverted Mesecon Signal =
+Controlled by Mesecon Signal =
 
 ## Machine names
 # $1: Tier
diff --git a/technic/machines/HV/forcefield.lua b/technic/machines/HV/forcefield.lua
index d5b5e54..f84cdb4 100644
--- a/technic/machines/HV/forcefield.lua
+++ b/technic/machines/HV/forcefield.lua
@@ -63,19 +63,21 @@ local function update_forcefield(pos, range, active)
 end
 
 local function set_forcefield_formspec(meta)
-	local formspec = "size[5.5,2.25]"..
-		"field[2.25,0.5;2,1;range;"..S("Range")..";"..meta:get_int("range").."]"
+	local formspec = "size[5,2.25]"..
+		"field[2,0.5;2,1;range;"..S("Range")..";"..meta:get_int("range").."]"
+	-- The names for these toggle buttons are explicit about which
+	-- state they'll switch to, so that multiple presses (arising
+	-- from the ambiguity between lag and a missed press) only make
+	-- the single change that the user expects.
 	if meta:get_int("mesecon_mode") == 0 then
-		formspec = formspec.."button[0,1;5.5,1;mesecon_mode_1;"..S("Ignoring Mesecon Signal").."]"
-	elseif meta:get_int("mesecon_mode") == 1 then
-		formspec = formspec.."button[0,1;5.5,1;mesecon_mode_2;"..S("Controlled by Positive Mesecon Signal").."]"
+		formspec = formspec.."button[0,1;5,1;mesecon_mode_1;"..S("Ignoring Mesecon Signal").."]"
 	else
-		formspec = formspec.."button[0,1;5.5,1;mesecon_mode_0;"..S("Controlled by Inverted Mesecon Signal").."]"
+		formspec = formspec.."button[0,1;5,1;mesecon_mode_0;"..S("Controlled by Mesecon Signal").."]"
 	end
 	if meta:get_int("enabled") == 0 then
-		formspec = formspec.."button[0.25,1.75;5,1;enable;"..S("%s Disabled"):format(S("%s Forcefield Emitter"):format("HV")).."]"
+		formspec = formspec.."button[0,1.75;5,1;enable;"..S("%s Disabled"):format(S("%s Forcefield Emitter"):format("HV")).."]"
 	else
-		formspec = formspec.."button[0.25,1.75;5,1;disable;"..S("%s Enabled"):format(S("%s Forcefield Emitter"):format("HV")).."]"
+		formspec = formspec.."button[0,1.75;5,1;disable;"..S("%s Enabled"):format(S("%s Forcefield Emitter"):format("HV")).."]"
 	end
 	meta:set_string("formspec", formspec)
 end
@@ -98,7 +100,6 @@ local forcefield_receive_fields = function(pos, formname, fields, sender)
 	if fields.disable then meta:set_int("enabled", 0) end
 	if fields.mesecon_mode_0 then meta:set_int("mesecon_mode", 0) end
 	if fields.mesecon_mode_1 then meta:set_int("mesecon_mode", 1) end
-	if fields.mesecon_mode_2 then meta:set_int("mesecon_mode", 2) end
 	set_forcefield_formspec(meta)
 end
 
@@ -117,7 +118,7 @@ local run = function(pos, node, active_object_count, active_object_count_wider)
 	local meta = minetest.get_meta(pos)
 	local eu_input   = meta:get_int("HV_EU_input")
 	local eu_demand  = meta:get_int("HV_EU_demand")
-	local enabled = meta:get_int("enabled") ~= 0 and (meta:get_int("mesecon_mode") == 0 or (meta:get_int("mesecon_mode") == 1 and meta:get_int("mesecon_effect") ~= 0) or (meta:get_int("mesecon_mode") == 2 and meta:get_int("mesecon_effect") == 0))
+	local enabled = meta:get_int("enabled") ~= 0 and (meta:get_int("mesecon_mode") == 0 or meta:get_int("mesecon_effect") ~= 0)
 	local machine_name = S("%s Forcefield Emitter"):format("HV")
 
 	local power_requirement = math.floor(