Added a scale to change game performance and running speed accordingly (#505)

config.lua

@@ -14,6 +14,10 @@ global.config = {
     -- New Scenario Features, appears in the "What's new" tab
     new_info_key = 'Nothing is new. The world is at peace',
 
+    performance = {
+        enabled = true,
+    },
+  
     -- adds a player list icon and keeps track of data.
     player_list = {
         enabled = true,

control.lua

@@ -39,6 +39,10 @@ end
 require 'features.train_station_names'
 require 'features.walkabout'
 
+if global.config.performance.enabled then
+    require 'features.performance'
+end
+
 -- GUIs the order determines the order they appear from left to right.
 -- These can be safely disabled if you want less GUI items.
 -- Some map presets will add GUI modules themselves.

features/performance.lua

@@ -0,0 +1,59 @@
+local Command = require 'utils.command'
+local format = string.format
+
+local Performance = {}
+
+---Sets the scale of performance.
+---1 means the game runs at normal game speed with full particles and normal walking speed
+---0.5 means the game runs at half speed, running speed is doubled and particles are halved
+---@param scale number
+function Performance.set_scale(scale)
+    if scale < 0.05 or scale > 1 then
+        error(format('Scale must range from 0.05 to 1'))
+    end
+
+    game.speed = scale
+    local movement_speed_scale = Performance.get_running_speed_modifier() - 1
+    for _, force in pairs(game.forces) do
+        force.character_running_speed_modifier = movement_speed_scale
+    end
+end
+
+---Returns the current scale
+function Performance.get_scale()
+    return game.speed
+end
+
+---Returns the running speed modifier
+function Performance.get_running_speed_modifier()
+    return 1 / game.speed
+end
+
+Command.add('set-performance-scale', {
+    description = 'Sets the performance scale between 0.05 and 1. Will alter the game speed and character running speed per force.',
+    arguments = {'scale'},
+    admin_only = true,
+    allowed_by_server = true,
+}, function (arguments, player)
+    local scale = tonumber(arguments.scale)
+    if scale == nil or scale < 0.05 or scale > 1 then
+        player.print('Scale must be a valid number ranging from 0.05 to 1')
+        return
+    end
+
+    Performance.set_scale(scale)
+    local p = game.print
+    p('## - Changed the game speed and running speed.')
+    p(format('## - Game speed: %.2f', Performance.get_scale()))
+    p(format('## - Force running speed: %.2f', Performance.get_running_speed_modifier()))
+end)
+
+Command.add('get-performance-scale', {
+    description = 'Shows the current performance scale.',
+}, function (_, player)
+    local p = player.print
+    p(format('Game speed: %.2f', Performance.get_scale()))
+    p(format('Running speed: %.2f', Performance.get_running_speed_modifier()))
+end)
+
+return Performance