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Uranium Template α

Official manual!!!!

Uranium Template is a Love2D-inspired NotITG game development template, focusing on keeping things as Lua-pure as possible with enough abstractions to make you feel like you're not dealing with Stepmania jank at all.

Uranium Template originally formed during the creation of a currently unreleased project, and since then I've went ahead and refined and polished it up to be usable on its own. Most of the design decisions came from experience using prototype versions of it!

Installation

Installation is the exact same as any other NotITG template:

  1. Get the latest template version from the Gitea releases page
  2. Unzip your installation zip, as you would a modfile
  3. Edit Song.sm in your editor of choice (ArrowVortex, NotITG) to include necessary metadata; replace silence.ogg with an actual track, if necessary
  4. Edit main.lua to do whatever you wish to do with it! The entirety of the src/ folder is yours!
  5. (Recommended) Install sumneko's Lua LSP and grab the latest NotITG typings here (put them in a folder like .typings!)

Distribution

After you're done with writing your file, be sure to take these steps to reduce the filesize and get your game ready for zipping up!

  • Remove MANUAL.md, docs/, .vscode/, .gitconfig, .gitignore and template/typings.lua. These are files that aren't necessary outside of a development environment!
  • Optionally, remove Song.sm.auto and Song.sm.old. These files may not exist depending on certain factors.
  • If you've followed step 4 during Installation, be sure to remove your typings folder (likely .typings)
  • If you're using Git, PLEASE REMOVE YOUR .git/ FOLDER!!!

If you're on Linux or have MSYS2/WSL/similar installed, you can use the distribution script.

Afterwards, it should be safe to zip everything up and send it over!

How do I start writing code?

main.lua is the entry-point for your code! From there, you can do the following:

If you're still a bit clueless, why not check out the Examples section?

Defining actors

Actors are defined in Uranium Template before any other callback runs, and are defined by a single function of their type:

local quad = Quad()
local sprite = Sprite('file/location.png')
local text = BitmapText('common', 'hello, world!')

All actors that take in filenames have their filenames starting from the root of the project; meaning if you had a file in myModFile/src/test.png, you'd have to pass in a filename of src/test.png. If an image is blank, or a single pink pixel, it hasn't loaded properly.

Initializing actors

Once you have an actor defined, you can run whatever methods you want.

Note Even though you get a fully functional actor, what you actually get is a proxied actor! What this means for you is that you really shouldn't call any getters on the actor, as it'll just return nil.

local text = BitmapText('common', 'hello, world!')
text:xy(scx, scy)
text:zoom(2.3)
text:rotationz(30)
text:diffuse(1, 0.8, 0.8, 1)

All methods that you run upon definition will be ran again at the start of every frame with uranium.config.resetOnFrameStart:

uranium.config.resetOnFrameStart(true)

local quad = Quad()
quad:xy(scx, scy)
quad:zoomto(60, 60)
quad:diffusealpha(1)

uranium.on('update',
  -- doesn't need a reset! it'll automatically zoomto 60, 60 and set its alpha to 1
  quad:Draw()
  quad:zoomto(120, 120)
  quad:diffusealpha(0.5)
  quad:Draw()
end)

If you want to avoid this for individual actors, or otherwise call getter methods, use the init callback:

local sprite = Sprite()

uranium.on('init', function()
  someTexture = sprite:GetTexture()
end)

Alternatively, you can also use the actors' individual InitCommands:

local sprite = Sprite()
sprite:addcommand('Init', function(self)
  someTexture = self:GetTexture()
end)

Or, you can disable the frame resetting functionality individually:

uranium.config.resetOnFrameStart(true)
local sprite = Sprite()
uranium.config.resetActorOnFrameStart(sprite, false)
sprite:Draw() -- will not be called per-frame

Accessing raw actors

As you may have noticed, when you print an actor defined with Uranium, it won't show up as an actor - it'll show up as a "proxy" of an actor. This is because we can't actually get actors created on demand in NotITG - what happens instead is you get an object that acts like an actor by calling all the same methods you pass into it, but isn't really one.

local q = Quad()
print(q) --> 'Proxy of Quad'

Typically, this doesn't matter; however, in certain contexts, it may be required for you to get the raw actor from a proxy actor. You can do this by accessing __raw on the actor - this is defined on all actors and is only available post-initialization.

local q = Quad()
print(q.__raw) --> nil
q:addcommand('Init', function()
  print(q.__raw) --> 'Sprite (168F7F78)'
end)

For most things that require this, there exist simple abstractions - applying shaders has setShader, setShaderfuck, etc., however in rare circumstances this may be useful. Please let me know if there's a use-case that I haven't accounted for!

Actor-specific notes

ActorFrameTexture

AFTs work in the same way as usual AFTs do in terms of ordering: they capture everything that was drawn to the screen before them:

quad:Draw() -- will be drawn to the AFT

aft:Draw()

sprite:Draw() -- will not be drawn to the AFT

See the AFT example for a quick setup to play around with, or the example in the aft library for a barebones setup. The ability to dynamically adjust at which point in the stack they render makes them a lot more powerful than you'd expect.

ActorFrame

To create an ActorFrame, first define it as a proper actor:

local af = ActorFrame()

Then, for all children that you want to put into the ActorFrame, run addChild:

local quad = Quad()
addChild(af, quad)
local sprite = Sprite()
addChild(af, sprite)

This will mess up rendering for those actors! This is because all actors that are outside the root ActorFrame of the template would be unaffected with the frame's transformations if they're drawn outside of their respective DrawFunctions. You'd want to then create a setup similar to this:

setDrawFunction(af, function() -- necessary to call this instead of af.SetDrawFunction for template internals reasons
  quad:Draw()
  sprite:Draw()
end)

uranium.on('update', function()
  af:Draw() -- would draw quad and sprite
end)

Nested AFs are supported. As with all complicated things in this template, check out the ActorFrame example for a simple working setup.

An additional extra feature Uranium Template adds to assist with rendering multiple instances is the ability to pass in arguments through Draw():

setDrawFunction(af, function(x, y)
  quad:xy(x, y)
  quad:Draw()
end)

uranium.on('update', function()
  for x = 0, 3 do
    for y = 0, 3 do
      af:Draw(x, y)
    end
  end
end)

ActorScroller

ActorFrame already has an extremely, extremely complicated setup powering it in the back-end; and ActorScroller is way too niche for me to give it the same treatment. Sorry!

BitmapText

If you want to specify theme-provided fonts, that's easy enough:

local text1 = BitmapText(nil, 'test') -- defaults to 'common'
local text2 = BitmapText('_wendy white', 'test')
local text3 = BitmapText('_misobold white', 'test')

However, providing custom fonts is a bit tedious due to a vanilla bug that's annoying to work around. In order to specify a custom font, consider the root path to be in template/. For example, if you want to load a font from your src/ folder, you'd do:

local text = BitmapText('../src/_inter v 22px.ini', 'test')

Textures

For convinience, Texture is a function that will give you a RageTexture from a filename without the actor. Equivalent to:

local sprite = Sprite('filename.png')
sprite:hidden(1)
local texture = sprite:GetTexture()
return texture

Shaders

Shaders cannot be manually defined on actors due to a technical limitation; plus, it wouldn't make much sense to integrate them in the same way that NotITG integrates shaders with the current XML behavior. In order to give an actor a shader, you need to define them seperately:

local sprite = Sprite('docs/uranium.png')
local shader = Shader('src/shader.frag') -- returns a RageShaderProgram

Afterwards, call setShader on your actor. You can call this outside of init, if you like.

setShader(actor, shader)
-- or
setShaderfuck(shader)
-- (don't forget to clearShaderfuck())

If you prefer, you can also inline shader code, as long as you don't mix files with inlined code in the same shader:

local shader = Shader([[
  #version 120

  void main() {
    gl_FragColor = vec4(0.420, 0.69, 1.0, 1.0);
  }
]])

Defining vertex shaders is done the same way, except with the second argument instead:

local shader = Shader('src/shader.frag', 'src/shader.vert')

To define a vertex shader and nothing else, you'll need to omit the fragment shader and put a nil in its place:

local shader = Shader(nil, 'src/shader.vert')

And last, if you want a no-op shader, you can just do a simple:

local noopShader = Shader()

Check the shader example if you just want something to play around with.

Callback usage

Callbacks are defined with uranium.on:

uranium.on('update', function(dt)
  -- runs every frame
end)

You can do this as many times as you like - it'll call every single function that's defined as update, not just the last!

If you return a non-falsy value in a callback, however, it'll cancel every other callback after it. This can be useful for, eg. capturing inputs and ensuring they don't get passed through to other callbacks on accident.

Default callbacks

These are the callbacks that are built into Uranium:

update(dt: number)

Called every frame. dt is the time passed since the last frame, the "deltatime".

init()

Called once on OnCommand. Every actor has been created, and the game should be starting shortly.

ready()

Fired on the first tick. A later version of init() where more things should be safe to use.

exit()

Should call when the player exits the file. Not properly tested yet.

focus(hasFocus: boolean)

Called whenever the window loses/gains focus. You can use this to reduce render quality on alt-tab.

Custom callbacks

Custom callbacks require no extra setup. Define your callback like usual:

uranium.on('somethingHappened', function(value)
  -- ...
end)

Then all you need to do to call it is:

uranium.call('somethingHappened', extra, values, go, here)

Callbacks support as many extra values as Lua supports arguments in a function - so let's just say you won't be running out of them any time soon.

Requiring files

require in Uranium works a lot like Lua's vanilla require, and is a direct copy of Mirin's require.

Say you have a file structure like this:

src/main.lua

local value = require('test')
print(value)

src/test.lua

return 'hello!'

Your setup would print 'hello!'.

All standard library modules are required with require, see further notes in Importing modules.

Configuration

Uranium Template's base functionality can be configured using uranium.config. You can access the raw values by requiring uranium.config, but this is currently undocumented.

uranium.config.resetOnFrameStart(bool: boolean)

Toggle actor resetting on frame start behavior by default. (Default: false)

uranium.config.resetActorOnFrameStart(actor: Actor, bool: boolean?)

Toggle actor resetting on frame start for individual actors. bool defaults to the opposite of your resetOnFrameStart config.

uranium.config.hideThemeActors(bool: boolean)

Toggle if theme actors (lifebars, scores, song names, etc.) are hidden. Must be toggled before init. (Default: true)

Standard library

The Uranium Template standard library is split up into a few convinient modules. This section aims to comprehensively document them all.

Importing modules

You can import a module like so:

require('stdlib.vector2D')

-- can use vector() here

Some modules won't export any globals, and therefore need to be loaded like so:

uwuify = require('stdlib.uwuify')
print(uwuify('hello!'))

These modules have a label near their header in this manual reading "Exports globals".

vector2D

Exports globals

vector2D is a simple 2D vector class system. For example, to define a vector:

local vec = vector2D(0, 0)
-- or
local vec = vector(0, 0)
-- or
local vec = vector(0)
-- or
local vec = vector()

Then add another vector to it:

vec = vec + vector(1)
print(vec) --> (1, 1)

Then measure its length:

local len = vec:length()
print(len) --> 1.4142135623730951
           --  (sqrt of 2)

Then rotate it and index it:

vec:rotate(180)

local x = vec.x
-- or
local x = vec[1]

print(x) --> -1

vector2D(x: number | nil, y: number | nil): vector2D

Creates a new vector. If only x is passed in, y = x. If no arguments are passed, x = y = 0.

vectorFromAngle(ang: number | nil, amp: number | nil): vector2D

Creates a new vector pointing in a specific angle. Specify ang in degrees. ang defaults to 0, amp defaults to 1.

vector2D:length(): number

Returns the vector's length. Equal to vector:distance(vector()).

vector2D:lengthSquared(): number

Returns the vector's length, squared. Here mainly for optimization purposes; this is a cheaper version of length() that's less accurate.

vector2D:angle(): number

Returns the vector's angle in degrees.

vector2D:rotate(ang: number): vector2D

Rotates the vector, setting its angle but keeping its length. Angle is provided in degrees.

vector2D:normalize(): vector2D

Normalizes the vector, setting its length to 1 but keeping its angle. Equal to vector:resize(1)

vector2D:resize(length: number): vector2D

Resizes the vector, setting its length but keeping its angle.

vector2D:unpack(): number, number

Unpacks the vector into its X and Y coordinates. Useful for quickly unpacking it into a function call:

local quad = Quad()
quad:xy(center:unpack())

vector2D:distance(vect: vector2D): number

Gets the distance between one vector and another.

vector2D:distanceSquared(vect: vector2D): number

Gets the distance between one vector and another, squared. Here mainly for optimization purposes; this is a cheaper version of distance() that's less accurate.

Operations

Here are all valid operations for vectors:

  • vector2D + number: equal to vector2D + vector2D(number)
  • vector2D + vector2D: adds the vectors' X and Y coordinates together, respectively, forming a new vector
  • vector2D - number: equal to vector2D - vector2D(number)
  • vector2D - vector2D: subtracts the vectors' X and Y coordinates, respectively, forming a new vector
  • vector2D * number: equal to vector2D * vector2D(number)
  • vector2D * vector2D: multiplies the vectors' X and Y coordinates together, respectively, forming a new vector
  • vector2D / number: equal to vector2D / vector2D(number)
  • vector2D / vector2D: divides the vectors' X and Y coordinates, respectively, forming a new vector
  • vector2D == vector2D: checks if the two vectors' X and Y coordinates are equivalent; returns false with any other type
  • -vector2D: negates the X and Y coordinates of the vector

color

Exports globals

color is a simple wrapper around all things color-related.

rgb(r: number, g: number, b: number, a: number | nil): color

Constructs a new color using the r, g, b and a values. Assumes all values are contained in the set [0, 1]. a defaults to 1.

hsl(h: number, s: number, l: number, a: number | nil): color

Constructs a new color using the h, s, l and a values using the HSL color model. Assumes all values are contained in the set [0, 1]. a defaults to 1; h wraps around.

hsv(h: number, s: number, v: number, a: number | nil): color

Constructs a new color using the h, s, v and a values using the HSV color model. Assumes all values are contained in the set [0, 1]. a defaults to 1; h wraps around.

shsv(h: number, s: number, v: number, a: number | nil): color

Equal to hsv(), except the hue value is smoothed using cubic smoothing. Not accurate, but produces neater-looking color blends for rainbow-shifting colors.

local rainbow = shsv(t, 1, 0.5)

hex(hex: string): color

Reads in a hex string and parses it into a color. Accepted hex string formats are #ffffff, ffffff, #fff and fff.

color:unpack(): number, number, number, number

Unpacks the color into its R, G, B and A values. Useful for diffuse:

local quad = Quad()
quad:diffuse(col:unpack())

color:rgb(): number, number, number

Returns the color's R, G and B values.

color:hsl(): number, number, number

Returns the color's H, S and L values in the HSL color model.

color:hsv(): number, number, number

Returns the color's H, S and V values in the HSV color model.

color:hex(): string

Returns the color's hex string representation in the format ffffff.

color:hue(h: number): color

Sets the color's hue value in the HSL/HSV color model.

color:huesmooth(h: number): color

Equivalent to color:hue(), except the hue value is smoothed using cubic smoothing. Not accurate, but produces neater-looking color blends for rainbow-shifting colors.

color:alpha(a: number): color

Sets the color's alpha channel.

color:malpha(a: number): color

Sets the color's alpha channel, multiplying the previous value with a.

color:invert(): color

Inverts the color.

color:grayscale(): color

Makes the color grayscale using a more accurate formula than just multiplying every value by 0.5.

color:hueshift(a: number): color

Shifts the color's hue by a.

Operations

Here are all valid operations for colors:

  • color + number: equal to color + rgb(number, number, number)
  • color + color: adds the colors' R, G and B values together, respectively, forming a new color
  • color - number: equal to color - rgb(number, number, number)
  • color - color: subtracts the colors' R, G and B values, respectively, forming a new color
  • color * number: equal to color * rgb(number, number, number)
  • color * color: multiplies the colors' R, G and B values together, respectively, forming a new color
  • color / number: equal to color / rgb(number, number, number)
  • color / color: divides the colors' R, G and B values, respectively, forming a new color
  • color == color: checks if the two colors' R, G and B values are equivalent; returns false with any other type

easable

A simple way of making a number easable. See this post for implementation details.

local easable = require('stdlib.easable')

local n = easable(0)

-- each time you want to set it, call this instead
n:set(value)
-- or
n:add(value)

-- to avoid the ease, do this instead
n:reset(value)

-- then, in your update function
uranium.on('update', function(dt)
  n:update(dt) -- multiply this image by some value to speed it up
  print(n.eased) -- retrieve the eased value
  print(n.target) -- retrieve the target value it's easing towards
end)

easable(default: number): easable

Creates a new easable, setting the default to default. Can technically be anything that has T * number, number - T and T + T defined, including a vector2D.

easable:set(new: number): void

Sets the target value (target) to new, easing the current value to the new value.

easable:add(new: number): void

Equivalent to easable:add(easable.target + new).

easable:reset(new: number): void

Sets the current (eased) and target (target) values to new, not easing the current value to the new value.

Operations

Every operation supported on the eased value is supported with an easable.

input

Defines callbacks

input is the library that handles everything input-related. Its main feature is providing the press and release callbacks, but you can also access the raw inputs with the inputs table (each value is -1 if the key is not pressed and the time at which it was pressed, estimated with t if it is pressed) and the raw inputs (ignoring callback returns) with rawInputs.

input.inputType

The input module can detect every input that the game can pass through the StepP<player><input><action>MessageCommand. This list is:

MenuLeft
MenuRight
MenuUp
MenuDown
Start
Select
Back
Coin
Operator
Left
Right
Up
Down
UpLeft
UpRight
ActionLeft
ActionRight
ActionUp
ActionDown
Action1
Action2
Action3
Action4
Action5
Action6
Action7
Action8
MenuStart

All of these inputs are neatly stored away in an enum called inputType. For instance, if you wanted to check if an input was Start, you would do:

local isStart = i == input.inputType.Start

input.directions

For your convinience, cardinal inputs are given a simple directions enum:

self.directions = {
  [self.inputType.Left] = {-1, 0},
  [self.inputType.Down] = {0, 1},
  [self.inputType.Up] = {0, -1},
  [self.inputType.Right] = {1, 0}
}

input.getInputName(i: inputType): string

Gets the name of an input. The reverse of indexing the inputType enum.

input.keyboardEquivalent

Mappings for the default keybinds for most keys. It's recommended to put them alongside the in-game representation in UIs to avoid confusion:

local inputName = input.getInputName(i)
local keyboardInput = input.keyboardEquivalent[i]
if keyboardInput then
  inputName = inputName .. ' (defaults to ' .. keyboardInput .. ')'
end
local dialog = 'Press ' .. inputName .. ' to boop' --> 'Press Start (defaults to Enter) to boop'

input.getInput(i: string, pn: number | nil): number

Shorthand for accessing input.inputs directly. If pn is not provided, it gets either of the players' inputs, prioritizing any that are held down.

input.inputs[1][input.inputType.Left] == input.getInput('Left', 1)

input.isDown(i: string, pn: number | nil): number

Shorthand for input.getInput(i, pn) ~= -1. If pn is not provided, players are ignored and it checks if either of the players have the input held down

press(input: inputType, pn: number)

Called when a player presses on a certain key.

release(input: inputType, pn: number)

Same as press, except for releasing a key.

A note about keyboard inputs

Working with left/down/up/right inputs can be tiring at times and it's hard to always fit designs to work with them. However, if you're willing to take a little compromise, you can also access all keyboard inputs. However, it's worth noting that this depends on NotITG's Simply Love (any forks will work fine too) both for your development environment and for all players. That being said, if you want to access the keyboard API, this is how you do it:

-- check if the user is using simply love at all
if not stitch then error('This modfile requires the Simply Love theme! https://github.com/TaroNuke/Simply-love-NotITG-ver.-') end

keyboard = stitch('lua.keyboard')

-- table that contains every keyboard key as the key and a boolean as the value
local buffer = keyboard.buffer
-- for example:
local isDebugKeyHeld = buffer['F3']

-- contains booleans for shift, ctrl, alt, win and altgr
local special = keyboard.special
local isDebugKeyAndShiftHeld = isDebugKeyHeld and special.shift

bitop

A Lua 5.0 port of bitop-lua. See their repository for documentation.

local bitop = require('stdlib.bitop')

scheduler

Defines callbacks

A simple scheduler.

local scheduler = require('stdlib.scheduler')

scheduler.schedule(when: number, func: function): number

Schedules a function to run in a specific amount of time. when is in seconds.

scheduler.scheduleInTicks(when: number, func: function): number

Schedules a function to run in a specific amount of update calls/ticks.

scheduler.unschedule(i: index): void

Unschedules a function. Use the index returned to you when originally scheduling the function.

scheduler.unscheduleInTicks(i: index): void

Unschedules a function in ticks. Use the index returned to you when originally scheduling the function.

binser

A NITG port of binser. Used for savedata serialization.

local binser = require('stdlib.binser')

local mydata = binser.serialize(45, {4, 8, 12, 16}, 'Hello, World!')

print(binser.deserializeN(mydata, 3))
-- 45	table: 0x7fa60054bdb0	Hello, World!

If you want to serialize custom types using the savedata module, check binser's Custom types section.

mirin

Defines callbacks

Exports globals

A copy of the Mirin Template by XeroOl (currently at 5.0.1), shoved in and ported for your convinience. Works exactly the same as regular Mirin.

A note about reset

Both Uranium Template and Mirin Template contain the global reset - Mirin Template uses it for mod resetting, while Uranium Template uses it for actor resetting. To avoid this collision, Uranium's reset has an alias called resetActor; Mirin will, by default, overwrite the usual reset. There's currently no way to change this.

savedata

Defines callbacks

A complete library for saving and loading arbitrary data to the user's profile. Uses binser for serialization. See Savedata example for an example of how to use this library.

savedata.initializeModule(name: string, forceIgnore: boolean): void

Initializes the savedata module. forceIgnore makes the function ignore name checks, but please don't use it unless you know what you're doing!!!

Generating a savedata name

Ideally, you'd generate a savedata name by generating a random 16-character string and appending it to your game's name. For instance:

savedata.initializeModule('myGameName_doAmaUOBIjiaSWyz')

The reason this is done is to avoid name collision - all modfiles share a global profile namespace to put their saved data in. To prevent it as much as possible, I've decided to force the user to generate a unique name that most likely won't be taken by anything else. forceIgnore completely ignores the 16-character and special/normal character checks.

savedata.s(data: table, name: string | nil): void

Creates a new module in your savedata. It uses data for defaults, then uses it for writing savedata to it and reading savedata from it; for instance, this would be correct usage:

local counter = {
  n = 0
}

savedata.s(counter)

uranium.on('init', function()
  print(counter.n) --> could be different from 0!
end)

uranium.on('update', function()
  counter.n = counter.n + 1 -- this will be saved the next time savedata.save is called
end)

By default, the name that's used for your module will be the folder your Lua file is located in, followed by its filename. This means you should not rely on the automatic name generation if your Lua file rests at the root of your file or if you're calling this function via loadstring or similar as it will create unpredictable module names that will change between setups and sometimes even game restarts. You can pass in any string you like to name, as long as it's unique in your project, to override this behavior.

savedata.save(instant: boolean): void

Saves the savedata onto the user's profile. It waits a single tick to do so and sets the boolean saveNextFrame to true; this is so that your game can display a loading frame for the temporary lagspike, as chances are, on lower-end setups with hard drives, this will momentarily freeze the game as it writes the profile. You can make it instantly save with instant.

savedata.load(): void

Loads the savedata. Shouldn't be called manually; this is automatically called on init().

savedata.getLastSave(): string[] | nil

Gets the last save time that persists between game restarts in the format {hour, minute, date, month, year}. If the game has not saved once, returns nil.

savedata.enableAutosave(): void

Enables autosave via exit(). Should hopefully mean data should never get lost.

env

Small module that contains a bit of information about the user's environment.

env.inEditor: boolean

Is true if the file is being played in the editor. Useful for debugging stuff.

env.onWine: boolean

Is true if the player is playing NotITG through Wine or similar.

rng

A xoshiro128** reimplementation in Lua.

rng.init(seed: number[] | nil): rng

Initializes a new RNG class. seed must be a table of size 4; if it is not provided, os.time() is used in its place. (Not os.clock()!!! Two RNG values created at the same time with no provided seed will be the same.)

rng(a: number | nil, b: number | nil): number

Acts identical to math.random(). Pass in no arguments to get a random float from 0 to 1, pass in one argument to get a random inclusive integer from 1 to a, pass in two arguments to get a random integer from a to b.

rng:int(min: number, max: number | nil): number

Generates an inclusive random integer. Pass in one argument to get a random integer from 1 to a, pass in two arguments to get a random integer from a to b.

rng:float(max: number | nil): number

Generates a random fractional number from 0 to max. max defaults to 1.

rng:bool(): boolean

Generates either a true or a false randomly.

rng:seed(seed: number): void

Sets the seed and advances the state.

rng:next(): number

Gets the next pseudo-random value. Recommended to use int, float, etc. over this.

rng:jump(): void

The jump function:

This is the jump function for the generator. It is equivalent to 2^64 calls to next(); it can be used to generate 2^64 non-overlapping subsequences for parallel computations.

rng:longJump(): void

The long-jump function:

This is the long-jump function for the generator. It is equivalent to 2^96 calls to next(); it can be used to generate 2^32 starting points, from each of which jump() will generate 2^32 non-overlapping subsequences for parallel distributed computations.

ease

Exports globals

A direct copy of Mirin Template's ease.lua, for convinience. See the docs for those here.

players

Exports globals

Pulls in the players as P[1-8] and P<1-8>.

require('stdlib.players')
P1:hidden(1)
P2:hidden(1)

profiler

Defines callbacks

A simple profiler for Uranium Template's callback system. Require it and it'll display in the left-top corner of your screen, showing what callback functions are taking the longest to run.

util

Exports globals

A big ol' module that holds a bunch of useful functions. These were too specific or too niche to go in any singular module; so they're all here now.

There's a bit too many functions to document, so I'd recommend just looking through the source code. I promise it doesn't bite.

aft

An AFT setup library. Sets up sprites and AFTs with sprite and aft, or all-in-one with aftSetup, making them ready for texturing use.

local aftlib = require('stdlib.aft')

-- aftSprite is a Sprite, set to the texture of aft, an ActorFrameTexture
local aft, aftSprite = aftlib.aftSetup()

noautoplay

A single function which can be called before ready() to disable autoplay for the duration of the file if the player has it on. Not tested.

require('stdlib.noautoplay')()

eternalfile

A single function which turns your file into an eternal, neverending file, until the player puts it out of its misery by exiting. The current beat will always go from 0 to 1 and start over once this is enabled. This also sets the notedata to nothing to avoid hitting padding mines.

require('stdlib.eternalfile')()

uwuify

uwuify = require('stdlib.uwuify')
print(uwuify('hello, world!')) --> hewwo, wowwd!

A very important library I don't see enough game engines include in their standard libraries.

Examples

Here are a couple of examples. All of these are standalone main.lua files that you can plug in and view the results of!

The obligatory

local text = BitmapText('common', 'Hello, world!')
text:xy(scx, scy)

uranium.on('update', function()
  text:Draw()
end)

Default Uranium Template code

require('stdlib.color')
require('stdlib.players')
P1:hidden(1)
P2:hidden(2)
require('stdlib.eternalfile')()

-- define a basic quad
local quad = Quad()
quad:xy(scx, scy)
quad:zoom(120)
quad:diffuse(0.8, 1, 0.7, 1)
quad:skewx(0.2)
uranium.config.resetActorOnFrameStart(quad)

-- define a sprite
local sprite = Sprite('docs/uranium.png')
sprite:xy(scx, scy)
sprite:zoom(0.4)
sprite:glow(1, 1, 1, 0)

-- let's add some text aswell
local text = BitmapText('common', 'hello, uranium template!')
text:xy(scx, scy + 100)

-- update gets called every frame
-- dt here refers to deltatime - the time that has passed since the last frame!
uranium.on('update', function(dt)
  -- let's rotate our quad
  quad:rotationz(t * 80)
  -- then shove it to the screen - similar to a drawfunction!
  quad:Draw()
  -- and you can do this multiple times of course!
  quad:zoomto(180, 180)
  quad:rotationz(t * 100)
  quad:diffusealpha(0.4)
  quad:skewx(0.1)
  quad:Draw()
  -- no need to reset properties - uranium resets all properties that you set upon definition!

  -- throw in the logo aswell, because why not
  -- zoom and glow is done for a quick-and-dirty outline
  sprite:zoom(sprite:GetZoom() * 1.1)
  sprite:glow(1, 1, 1, 1)
  sprite:Draw()
  -- if you can't wait until the start of a frame to reset properties, you can manually do it
  reset(sprite)
  sprite:Draw()

  -- for the text, get a rainbow color
  local col = shsv(t * 0.6, 0.5, 1)
  text:diffuse(col:unpack()) -- the :unpack() is necessary when passing into :diffuse()
  -- wag the text
  text:rotationz(math.sin(t * 2) * 10)
  text:Draw()
end)

Simple platformer base

require('stdlib.vector2D')
local input = require('stdlib.input')

-- constants are just those that felt nice to me. this is completely valid to do in gamedev
local DAMPING = 1/9500
local SPEED = 2
local JUMP_FORCE = 32
local GRAVITY = 123
local PLAYER_SIZE = 50

local groundY = sh * 0.8

local protagActor = Quad()
protagActor:zoomto(PLAYER_SIZE, PLAYER_SIZE)
local ground = Quad()
ground:zoomto(sw, 4)
ground:xy(scx, groundY + PLAYER_SIZE/2 + 4/2)

local coverQuad = Quad()
coverQuad:diffuse(0, 0, 0, 0.6)
coverQuad:xywh(scx, scy, sw, sh)

local pos = vector(scx, groundY)
local vel = vector(0, 0)
local hasHitGround = true -- let's define this so that you can't jump mid-air

-- called whenever the player recieves an input
uranium.on('press', function(i)
  if i == input.inputType.Up and hasHitGround then
    vel.y = vel.y - JUMP_FORCE
    hasHitGround = false
    return true -- input eaten! further callbacks won't recieve this
  end
end)

uranium.on('update', function(dt)
  -- respond to l/r inputs
  if input.isDown('Left') then
    vel.x = vel.x - SPEED
  end
  if input.isDown('Right') then
    vel.x = vel.x + SPEED
  end

  -- apply gravity
  vel.y = vel.y + GRAVITY * dt

  -- update position, apply damping to velocity
  pos = pos + vel
  vel = vel * math.pow(DAMPING, dt)

  -- make sure the player can't clip through the ground
  if pos.y >= groundY then
    pos.y = groundY
    if vel.y >= 0 then vel.y = 0 end
    hasHitGround = true
  end

  -- make sure the player can't leave the screen on accident
  pos.x = math.min(pos.x, sw - PLAYER_SIZE/2)
  pos.x = math.max(pos.x, 0  + PLAYER_SIZE/2)

  -- slightly cover up the regular nitg gameplay
  coverQuad:Draw()

  -- draw them!
  protagActor:xy(pos.x, pos.y)
  protagActor:Draw()

  -- draw the ground
  ground:Draw()
end)

AFTs

VSync recommended

local aftSetup = require('stdlib.aft')
require('stdlib.color')
require('stdlib.vector2D')

local coverQuad = Quad()
coverQuad:diffuse(0, 0, 0, 1)
coverQuad:xywh(scx, scy, sw, sh)

local testQuad = Quad()
testQuad:zoom(50)

local aft = ActorFrameTexture()

local aftSprite = Sprite()
aftSetup.sprite(aftSprite)
aftSprite:diffusealpha(0.99)
aftSprite:zoom(1.01)
aftSprite:rotationz(0.2)

aft:addcommand('Init', function(self)
  aftSetup.aft(aft) -- put this here; else it'll recreate it every frame!
  aftSprite:SetTexture(self:GetTexture())
end)

local text = BitmapText('common', 'uranium template!')
text:xy(scx, scy)

uranium.on('update', function(dt)
  coverQuad:Draw()

  aftSprite:Draw()

  local rainbow = shsv(t * 1.2, 0.5, 1)

  testQuad:xy((vectorFromAngle(t * 160, 100) + vector(scx, scy)):unpack())
  testQuad:diffuse(rainbow:unpack())
  testQuad:zoom(50 * math.random())
  testQuad:Draw()

  aft:Draw()

  text:Draw()
end)

Shader test

-- define a sprite
local sprite = Sprite('docs/uranium.png')
sprite:xy(scx, scy)
sprite:zoom(0.4)
sprite:rotationz(0)
sprite:diffusealpha(1)

-- add our heat shader
local shader = Shader([[
#version 120

// took the common heat.frag and integrated simplex noise into it
// now it looks better -oat

uniform float tx,ty,yo;
uniform float scale;

varying vec2 textureCoord;
varying vec4 color;
uniform sampler2D sampler0;

vec2 hash( vec2 p ) // replace this by something better
{
	p = vec2( dot(p,vec2(127.1,311.7)), dot(p,vec2(269.5,183.3)) );
	return -1.0 + 2.0*fract(sin(p)*43758.5453123);
}

float noise( in vec2 p )
{
  const float K1 = 0.366025404; // (sqrt(3)-1)/2;
  const float K2 = 0.211324865; // (3-sqrt(3))/6;

	vec2  i = floor( p + (p.x+p.y)*K1 );
  vec2  a = p - i + (i.x+i.y)*K2;
  float m = step(a.y,a.x); 
  vec2  o = vec2(m,1.0-m);
  vec2  b = a - o + K2;
	vec2  c = a - 1.0 + 2.0*K2;
  vec3  h = max( 0.5-vec3(dot(a,a), dot(b,b), dot(c,c) ), 0.0 );
	vec3  n = h*h*h*vec3( dot(a,hash(i+0.0)), dot(b,hash(i+o)), dot(c,hash(i+1.0)));
  return dot( n, vec3(70.0) );
}

vec2 SineWave(vec2 p) {
  // wave distortion
  float x = noise(vec2(p.x * scale, p.y * scale) * 30.5 + tx) * 0.05 * yo;
  float y = noise(vec2(-p.y * scale, p.x * scale) * 29.3 - ty) * 0.05 * yo;
  return vec2(p.x+x, p.y+y);
}

void main() {
  vec4 col = texture2D(sampler0, SineWave(textureCoord));

  gl_FragColor = col * color;
}
]])
setShader(sprite, shader)

uranium.on('update', function()
  shader:uniform1f('yo', 1)
  shader:uniform1f('scale', 0.25)

  shader:uniform1f('tx', t)
  shader:uniform1f('ty', t)

  sprite:zoom(0.8)
  sprite:diffusealpha(0.6)
  sprite:Draw()

  reset(sprite)
  shader:uniform1f('yo', 0)
  sprite:Draw()
end)

Savedata example

local input = require('stdlib.input')
local savedata = require('stdlib.savedata')

savedata.initializeModule('example_tTsrDBMgsA5eWzaZ') -- change this!!

local save = {
  leftPresses = 0,
  rightPresses = 0,
}

savedata.s(save)

local text = BitmapText('common', '')
text:xy(scx, scy)

uranium.on('press', function(key)
  if key == input.inputType.Left then
    save.leftPresses = save.leftPresses + 1
  elseif key == input.inputType.Right then
    save.rightPresses = save.rightPresses + 1
  elseif key == input.inputType.Down then
    savedata.save()
  end
end)

uranium.on('update', function(dt)
  text:settext(
    'left presses: ' .. save.leftPresses .. '\n' ..
    'right presses: ' .. save.rightPresses
  )
  text:Draw()

  if savedata.saveNextFrame then
    text:xy(scx, scy + 50)
    text:settext('saving!')
    text:Draw()
  end
end)

Simple ActorFrame setup

local af = ActorFrame()
af:xy(scx, scy)

local sprite = Sprite('docs/uranium.png')
addChild(af, sprite)
sprite:zoom(0.4)
sprite:glow(1, 1, 1, 0)

local quadsAF = ActorFrame()
addChild(af, quadsAF)

local quads = {}
for i = 1, 50 do
  local q = Quad()
  q:zoom(math.random(30, 50))
  q:xy(math.random(-200, 200), math.random(-200, 200))
  q:diffusealpha(0.7)
  q:rotationx(math.random(0, 360))
  q:rotationy(math.random(0, 360))
  q:rotationz(math.random(0, 360))
  table.insert(quads, q)
  addChild(quadsAF, q)
end

setDrawFunction(quadsAF, function()
  for _, v in ipairs(quads) do
    v:Draw()
  end

  quadsAF:rotationz(-t * 30)
end)

setDrawFunction(af, function()
  quadsAF:Draw()

  af:rotationz(t * 90)
  af:zoom(1 + math.sin(t) * 0.2)

  sprite:xy(math.cos(t) * 100, math.sin(t) * 100)

  sprite:zoom(sprite:GetZoom() * 1.1)
  sprite:glow(1, 1, 1, 1)
  sprite:Draw()
  reset(sprite)
  sprite:Draw()
end)

uranium.on('update', function()
  af:Draw()
end)

Credits

XeroOl - Mirin Template was a massive design inspiration; early stages of this template borrowed lots of code from it and the current require implementation has been grabbed directly from it
Mayflower, Aura - Testing, design help
mangoafterdawn - The Uranium Template logo!