evlightning's Introduction

EvLightning

EvLightning is a Roblox Lua library that aims to generate realistic-looking lightning bolts. This could be used to easily add lightning strike effects to your game.

Usage

local LightningBolt = require(path.to.EvLightning)

local myBolt = LightningBolt.new(Vector3.new(0, 400, 0), Vector3.new(0, 0, 0), {
  color = BrickColor.new("Really red");
  -- More options are available, see below...
})
myBolt:Draw(workspace)

A lightning bolt is split into lines, and where the lines meet is considered to be a "bend". At each bend, there is a chance to create a fork, which will create another bolt with its own bends, which in turn have chances to create their own forks, etc. You can control how many bends are in the bolt and the chance of creating a fork at each bend.

API

LightningBolt LightningBolt.new(Vector3 from, Vector3 to[, dictionary options])

Returns an instance of LightningBolt. Automatically generates in the constructor, but further methods must be called on the returned instance to render the bolt.

Options

There are a number of options that you can pass in a third argument to LightningBolt.new in the form of a table dictionary. All options are optional, and have default values.

Option name	Description	Default value	Type
seed	A numerical seed which could be used to generate the same lightning bolt across a network.	Random	Number
bends	The number of bends the main bolt should have.	6	Integer
fork_bends	The number of bends to put into forks off of the main bolt.	2	Integer
fork_chance	The chance to create a new fork off of each bend. (0-100)	50	Number
transparency	The transparency of the main bolt. Transparency is reduced at every fork.	0.4	Number
thickness	The thickness of the main bolt. Thickness is reduced at every fork.	1	Number
max_depth	The maximum depth that forks can reach off the main bolt, which is depth 0.	3	Integer
color	The color of the bolt	White	BrickColor or Color3
material	The material of the bolt	Enum.Material.Neon	Enum.Material
decay	The number of seconds for the bolt to exist after being drawn.	Infinite	Number

Note that the fork_chance option is not an equal chance for every bend in the bolt. The chance is distributed in a gradient down the length of the bolt, meaning that if the fork_chance is 50, then at the very top it will be 0, at the middle it will be 25, and at the very bottom it will be 50. This is done so that less forks are generated towards the top, which makes the bolt look more realistic. If you need to create upwards-forking lightning, then simply reverse the to and from arguments.

void bolt:Draw([Instance parent = Workspace])

Draws the lightning bolt in the world with the given options. An optional argument, parent, can be passed, which will be the parent of the generated lightning bolt parts. If this argument is omitted, there will be a new model created in Workspace containing the bolt parts.

array bolt:GetLines()

Returns a table of tables, containing the line information. The member tables have the keys origin, goal, and depth. This is only necessary if you want to draw the lightning bolt manually (i.e. not calling Draw).

{
	{
		origin 	= Vector3 origin,
		goal 	= Vector3 endpoint,
		depth	= Number depth
	},
	{
		origin 	= Vector3 origin,
		goal 	= Vector3 endpoint,
		depth	= Number depth
	},
	-- ...
}

void bolt:Destroy()

If the lightning bolt has been drawn, this method will destroy the model that was created.

dictionary bolt:GetOptions()

Returns a table of the options that were passed into the constructor. Default values are not applied here.

bool bolt:IsDestroyed()

Returns true if the lightning bolt has either been destroyed or has decayed.

bool bolt:IsDrawn()

Returns true of the Draw method has been called on this particular instance.

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evlightning's Issues

Modification Requests

Please do not use game.Workspace, as Workspace can be renamed. Instead use game:GetService("Workspace") or workspace
Instead of instantiating a part with inline default values, please create a global partTemplate and Clone() it and change its properties as appropriate. Also, please do not mix string enums with enums (style issue). Also, please set the parent last, as it is much faster to do so. This should also be encouraged by the use of Clone():

local partTemplate = Instance.new("Part")
partTemplate.Anchored = true
partTemplate.CanCollide = false
partTemplate.BrickColor = BrickColor.new("White")
partTemplate.Material = Enum.Material.Neon
partTemplate.TopSurface = Enum.SurfaceType.Smooth
partTemplate.FormFactor = Enum.FormFactor.Custom
partTemplate.BottomSurface = Enum.SurfaceType.Smooth

-- within function LightningBolt:Draw(parent)
local part = partTemplate:Clone()

if self.options.color then
	part.BrickColor = self.options.color
end

if self.options.material then
	part.Material = self.options.material
end

part.Size = Vector3.new(1-line.depth*2*0.1, 1-line.depth*2*0.1, (line.origin-line.goal).magnitude+0.5)
part.CFrame = CFrame.new((line.goal+line.origin)/2, line.goal)
part.Transparency = line.transparency
part.Parent = model

Please do not iterate through arrays using pairs. This will make the ghost of simple for loops come for you.

for i = 1, #t do
	print(t[i])
end

When constructing a new array, especially when it's a copy, repeatedly doing #t for every write operation is going to make my head spin. For a non-copy, a count variable is preferable. A copy can easily be written as so:

local runLines = {}
for i = 1, #self.lines do
	runLines[i] = self.lines[i]
end

If you want a method function to be strictly internal, you might consider to do the following:

function LightningBolt:generateBolt() -- What you have
local function generateBolt(self) -- A way to truly hide API you don't want exposed

Please be consistent on your spacing around binary operators. "3 + 5" or "3+5", but pick one and stick with it.
This information is already contained within the comments of the module. Why would it ever be necessary to have this?

LightningBolt._version = 1

It is STRONGLY preferable to not recursively generate objects within objects (#L134). If possible, please avoid unnecessary abstraction for internal syntactic sugar. Only do it if you absolutely have to.
Color is preferable to BrickColor (API change request)

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