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This page contains general purpose code snippets.

Contents 1 Mathematical Snippets 1.1 Generating Pseudo-Random Numbers 1.2 Better Rounding 1.3 Toggling a Boolean 1.4 Getting the Position of a Point between Two Vectors 2 Variables 2.1 Defining Multiple Variables 2.2 Using OR 2.3 Switching Two Variables without Making a Third 3 Loops and statements 3.1 Looping through Every Character in a String 3.2 Using 'repeat, until' 3.3 Doing 'if .. then ... else' in One Line 3.4 Returning 'if .. then ... else' 4 Miscellaneous 4.1 Using an Unlimited Number of Arguments 4.2 Fading Between Two Colors 4.3 Using 'print' Effectively 4.4 Finding all the Functions or Variables in an Object 4.5 Adding an Event Hook 4.6 Making a Custom SpawnMenu 4.7 Smooth health bar example 4.8 Getting a player using their SteamID

Mathematical Snippets

Generating Pseudo-Random Numbers

 
math.random( 3, 9 ) // Generates a random integer between 3 and 9 inclusively.
math.Rand( 3, 9 ) // Generates a random real number (floating point) between 3 and 9 inclusively.
 

Better Rounding

• Because, frankly, Garry's rounding function sucks.
• This allows you to round to a decimal point instead of to a whole number.

 
/* Rounds to the 3rd decimal point
 * Usage: math.AdvRound( 1.6443132, 3 ); 
 */
function math.AdvRound( val, d )
	d = d or 0;
 
	return math.Round( val * (10 ^ d) ) / (10 ^ d);
end
 

Toggling a Boolean

 
local Boolean = false
-- Toggle the boolean.
Boolean = not Boolean
-- or, in C-style notation:
Boolean = !Boolean
 

Getting the Position of a Point between Two Vectors

This will return the position of a point between two vectors. The count is a percentage.

 
function LinearCalc(PosA, PosB, Percent)
    return PosA + (PosB - PosA)*Percent
end
 

or

 
local percent = 0.5 // 1.0 being 100%
LerpVector( percent, pos1, pos2)
 

Variables

Defining Multiple Variables

 
-- X = 1, Y = 2, Z = 3.
local X, Y, Z = 1, 2, 3
 

Using OR

 
-- If Y is non-nil, set X to Y; otherwise, set X to 0.
local X = Y or 0
 

Switching Two Variables without Making a Third

 
a,b = b,a
 

Loops and statements

Looping through Every Character in a String

 
 for i = 1, string.len( strToLoop ) do
    local Character = string.sub( strToLoop, i, i )
     -- Do stuff with Character here.
end
 

Using 'repeat, until'

 
repeat
num = math.random( 200 )
Msg( num .. "\n" )
until( num == 25 )
 

Doing 'if .. then ... else' in One Line

 
local value = ( x > 1 ) && "X is greater" || "X isn't greater";
--and in STD. Lua notation:
local value = ( x > 1 ) and "X is greater" or "X isn't greater";
--basic format for Inline Conditionals:
local value = (Condition) and TrueValue or FalseValue;
 

Returning 'if .. then ... else'

 
return current < max and func( current + 1, max ) or nil
 

Miscellaneous

Using an Unlimited Number of Arguments

 
function takesMultipleArgs( ply, name, ... )
    print( name, ply:GetPos() )    
 
    callAnotherFunction( "hi there", ... )
 
    for k, v in pairs( {...} ) do
       print( v .. "\n" )
     end
 end
 

Fading Between Two Colors

 
function Fade( a, b, frac, alpha )
    local res, me
     res = Color( 0, 0, 0, alpha )
     me = ( 1 - frac )
    res.r = ( a.r * me ) + ( b.r * frac )
    res.g = ( a.g * me ) + ( b.g * frac )
    res.b = ( a.b * me ) + ( b.b * frac )
    return res
end
 

Simpler approach, also fades the alpha

 
function LerpColor(frac,from,to)
	local col = Color(
		Lerp(frac,from.r,to.r),
		Lerp(frac,from.g,to.g),
		Lerp(frac,from.b,to.b),
		Lerp(frac,from.a,to.a)
	)
	return col
end
 

Using 'print' Effectively

 
-- print, as you ought to know, will echo a message to the gmod console.
print( "lol" )
 
 -- You can pass multiple arguments to print and it will automatically format them with tabs in between them.
print( "lol", "wut?" )
 
-- It's more useful than that though.  Print will automatically call tostring on any argument you throw at it, even userdata.
print( 42 )
print( Vector( 1, 2, 3 ) )
print( LocalPlayer() )
 
 -- This makes it great for quick debugging and getting information.
for _,ent in pairs( ents.GetAll() ) do
    print( ent, ent:GetPos() )
end
 

Finding all the Functions or Variables in an Object

Do PrintTable( FindMetaTable( "ObjectName" ) ) to get the functions, and PrintTable( object:GetTable() ) to get the variables. (Not every object has GetTable defined though.)

e.g.

 
PrintTable( FindMetaTable( "Entity" ) )
PrintTable( Entity( 1 ):GetTable() )
 

For more information: Metatable

Posted by TetaBonita on FP Forums.

Adding an Event Hook

The middle parameter is a unique name to give the hook, this assures that you won't spawn multiple hooks for doing the same thing.

hook.Add( "GUIMousePressed", "MorphMouseDown", MouseDownFunction )

Making a Custom SpawnMenu

Adding this to your cl_init.lua on your gamemode will add a custom spawnmenu to your server. Add more to the Table to add your own props.

 
function proplist()
		print ("List Opening")
		local props = {}
 
	props[1] = "models/props_junk/garbage_milkcarton002a.mdl"
	props[2] = "models/props_junk/PopCan01a.mdl"
	props[3] = "models/props_junk/garbage_takeoutcarton001a.mdl"
	props[4] = "models/props_junk/watermelon01.mdl"
	props[5] = "models/props_junk/garbage_metalcan001a.mdl"
	props[6] = "models/props_lab/box01a.mdl"
	props[7] = "models/props_lab/box01b.mdl" -- You can add more such as props[8] = "models/path/model.mdl" to add your own.
 
	local slframe = vgui.Create("DFrame")
	local IconList = vgui.Create("DPanelList", slframe)
 
	slframe:Center()
	slframe:SetSize(250,200)
	slframe:SetTitle("Prop Catalog")
	slframe:MakePopup()
 
	IconList:EnableVerticalScrollbar( true )
	IconList:EnableHorizontal( true )
	IconList:SetPadding( 4 )
	IconList:SetPos(10,30)
	IconList:SetSize(200,160)
 
	for k,v in pairs(props) do
	local icon = vgui.Create( "SpawnIcon", IconList )
	icon:SetModel( v )
	IconList:AddItem( icon )
	icon.DoClick = function( icon ) surface.PlaySound( "ui/buttonclickrelease.wav" ) RunConsoleCommand("gm_spawn", v) end
	end
end
concommand.Add("slist", proplist)
 
function GM:OnSpawnMenuOpen( ply )
LocalPlayer():ConCommand("slist")
end
 

Posted by Noforgivin from Facepunch forums.

Smooth health bar example

This creates a nice smooth health bar that fades from green to red.

-- Created by CowThing
local smooth = 0 -- Setting up the variable that will get smoothed.
hook.Add("HUDPaint", "HealthBar", function()
 
	local health = math.Clamp(LocalPlayer():Health(), 0, 100)	-- clamps the health to [0, 100] meaning it will not go above 100 or below 0
	smooth = math.Approach(smooth, health, 50*FrameTime())		-- smooth the health value, this looks a lot better than just using the raw health value.
									-- You should use FrameTime() for things like this so it will look smooth even if your FPS is low.
 
	local red = (1 - smooth/100)^(1/2) * 255	-- Create a linear equation for the red value, as health drops red increases.
	local grn = (smooth/110)^(1/2) * 255		-- same for green, as health drops green decreases.
	local blu = (smooth/200)^2 * 255		-- and for blue
 
	local col = Color(red, grn, blu) -- create a single color object with the values.
 
	local w, h = 60, 200
	local spacing = 32
 
	local equation = (h-8)*(smooth/100)+8 -- this equation is so the bar will shrink as you lose health.
 
	draw.RoundedBox(
		4,
		ScrW() - w - spacing - 2,
		ScrH() - h - spacing - 2,
		w + 4,
		h + 4,
		Color( 30, 30, 30 )
	)
 
	draw.RoundedBox(
		4,
		ScrW() - w - spacing,
		ScrH() - equation - spacing,
		w,
		equation,
		col
	)
 
end)

Getting a player using their SteamID

This extension for the player library has many uses.

function player.GetBySteamID(ID)
	local PTab = player.GetAll()
	for p=1,#PTab do
		if ID == PTab[p]:SteamID() then
			return PTab[p]
		end
	end
	return false
end