allow multiple transmitters on same frequency

hud.lua

@@ -17,7 +17,7 @@ function ham_radio.toggle_hud(player)
 
   -- if hud is already enabled, pass
   if ham_radio.is_receiver_wielded[name] then
-	return true
+	  return true
   end
 
   -- create hud
@@ -70,15 +70,20 @@ function ham_radio:update_hud_display(player)
     return
   end
 
-  local transmitter_signal = 0
+  local signal_power = 0
   local name = player:get_player_name()
   local meta = player:get_wielded_item():get_meta()
   local frequency = meta:get_string("frequency")
   
   if frequency ~= nil and frequency ~= "" then
-    local transmitter = self.read_transmitter(frequency)
-    if transmitter.pos then
-      transmitter_signal = self:locate_transmitter(player, transmitter.pos)
+    local transmitters = self.read_transmitters(frequency)
+    
+    for key, transmitter in pairs(transmitters) do
+      local transmitter_signal = self:locate_transmitter(player, transmitter.pos)
+      if transmitter_signal > signal_power then
+        -- use max power from transmitters nearby
+        signal_power = transmitter_signal
+      end
     end
   end
   local text = "FQ "..tostring(meta:get_string("frequency"))
@@ -86,7 +91,7 @@ function ham_radio:update_hud_display(player)
   player:hud_change(
     self.playerhuds[name].signal_level,
     "scale",
-    { x = transmitter_signal/50 or 0.1, y = 1 } -- x scale should be 0-2
+    { x = signal_power/50 or 0.1, y = 1 } -- x scale should be 0-2
   )
 end
 

init.lua

@@ -11,20 +11,35 @@ ham_radio = {
   }
 }
 
-function ham_radio.save_transmitter(frequency, transmitter_data)
-  mod_storage:set_string(tostring(frequency), minetest.write_json(transmitter_data))
+function ham_radio.save_transmitter(frequency, pos, transmitter_properties)
+  local transmitters = mod_storage:get_string(tostring(frequency))
+  local transmitter_list = {}
+  if transmitters ~= "" then
+    transmitter_list = minetest.parse_json(transmitters)
+  end
+  transmitter_list[minetest.pos_to_string(pos, 0)] = transmitter_properties
+  mod_storage:set_string(tostring(frequency), minetest.write_json(transmitter_list))
 end
 
-function ham_radio.read_transmitter(frequency)
-  local transmitter_data = mod_storage:get_string(tostring(frequency))
-  if transmitter_data ~= nil and transmitter_data ~= "" then
-    return minetest.parse_json(transmitter_data)
+function ham_radio.read_transmitters(frequency)
+  local transmitters = mod_storage:get_string(tostring(frequency))
+  if transmitters ~= "" then
+    return minetest.parse_json(transmitters)
   end
   return {}
 end
 
-function ham_radio.delete_transmitter(frequency)
-  mod_storage:set_string(tostring(frequency), nil)
+function ham_radio.delete_transmitter(frequency, pos)
+  local transmitters = mod_storage:get_string(tostring(frequency))
+  if transmitters ~= "" then
+    local transmitter_list = minetest.parse_json(transmitters)
+    transmitter_list[minetest.pos_to_string(pos, 0)] = nil
+    if next(transmitter_list) == nil then
+      mod_storage:set_string(tostring(frequency),"")
+    else
+      mod_storage:set_string(tostring(frequency), minetest.write_json(transmitter_list))
+    end
+  end
 end
 
 dofile(modpath.."/craft.lua")

transmitter.lua

@@ -23,6 +23,11 @@ minetest.register_node("ham_radio:transmitter", {
     )
     meta:set_string("infotext", '')
   end,
+  after_place_node = function(pos, placer)
+    local meta = minetest.get_meta(pos);
+    local name = placer:get_player_name()
+    meta:set_string('operated_by', name)
+  end,
   on_receive_fields = function(pos, formname, fields, sender)
     if fields.quit ~= "true" then
       return
@@ -31,10 +36,15 @@ minetest.register_node("ham_radio:transmitter", {
       local meta = minetest.get_meta(pos)
       meta:set_string("frequency", fields.frequency)
       meta:set_string("infotext", 'Frequency: '..fields.frequency)
-      ham_radio.save_transmitter(fields.frequency, {
-        pos = pos,
-        broadcast_message = "Test Ham Radio Broadcast!"
-      })
+      ham_radio.save_transmitter(
+        fields.frequency,
+        pos,
+        {
+          pos = pos,
+          broadcast_message = "Test Ham Radio Broadcast!",
+          operated_by = meta:get_string('operated_by')
+        }
+      )
     end
   end,
   can_dig = function(pos,player)
@@ -44,6 +54,6 @@ minetest.register_node("ham_radio:transmitter", {
     return inv:is_empty("main") and not minetest.is_protected(pos, name)
   end,
   after_dig_node = function(pos, oldnode, oldmetadata, player)
-    ham_radio.delete_transmitter(oldmetadata.fields.frequency)
+    ham_radio.delete_transmitter(oldmetadata.fields.frequency, pos)
   end
 });