Added /rainbow

modules/commands/rainbow.lua

@@ -0,0 +1,54 @@
+local Commands = require 'expcore.commands'
+local format_chat_colour = ext_require('expcore.common','format_chat_colour')
+
+local function step_component(c1,c2)
+    if c1 < 0 then
+        return 0,c2+c1
+    elseif c1 > 1 then
+        return 1,c2-c1+1
+    else
+        return c1,c2
+    end
+end
+
+local function step_color(color)
+    color.r,color.g = step_component(color.r,color.g)
+    color.g,color.b = step_component(color.g,color.b)
+    color.b,color.r = step_component(color.b,color.r)
+    color.r = step_component(color.r,0)
+    return color
+end
+
+local function next_color(color,step)
+    step = step  or 0.1
+    local new_color = {r=0,g=0,b=0}
+    if color.b == 0 and color.r ~= 0 then
+        new_color.r = color.r-step
+        new_color.g = color.g+step
+    elseif color.r == 0 and color.g ~= 0 then
+        new_color.g = color.g-step
+        new_color.b = color.b+step
+    elseif color.g == 0 and color.b ~= 0 then
+        new_color.b = color.b-step
+        new_color.r = color.r+step
+    end
+    return step_color(new_color)
+end
+
+Commands.new_command('rainbow','Sends an rainbow message in the chat')
+:add_param('message',false) -- action that is done by the player, just text its meaningless
+:enable_auto_concat()
+:register(function(player,message,raw)
+    local player_name = player and player.name or '<Server>'
+    local player_color = player and player.color or nil
+    local color_step = 3/message:len()
+    if color_step > 1 then color_step = 1 end
+    local current_color = {r=1,g=0,b=0}
+    local output = format_chat_colour(player_name..': ',player_color)
+    output = output..message:gsub('%S',function(letter)
+        local rtn = format_chat_colour(letter,current_color)
+        current_color = next_color(current_color,color_step)
+        return rtn
+    end)
+    game.print(output)
+end)