Lunar

A Lua library for AABB collisions resolutions (alpha version).

Example (using LÖVE)

local lunar = require 'lunar'

function love.load()
	player = lunar.hitbox:new(0, 0, 32, 64) --x, y, width, height
	tile = lunar.tile:new(150, 150, 32)     --x, y, tile size
	speed = 0
end

function love.update(dt)
	speed = 150 * dt
	if love.keyboard.isDown("up")	then player.y = player.y - speed end
	if love.keyboard.isDown("down")	then player.y = player.y + speed end
	if love.keyboard.isDown("left")	then player.x = player.x - speed end
	if love.keyboard.isDown("right")then player.x = player.x + speed end
	player:solveCollision(tile) --Solving all collisions between 'player' and 'tile'
end

function love.draw()
	love.graphics.rectangle('fill', player.x, player.y, player.w, player.h)
	love.graphics.rectangle('line', tile.x, tile.y, tile.s, tile.s)
end

Installing

Just download and require the lunar.lua script:

local lunar = require 'lunar'

How to use

1. Create a hitbox

lunar.hitbox:new(x, y, width, height)

x: number
y: number
width: number
height: number

Returns
hitbox: instance

Instance attributes
hitbox.x: number
hitbox.y: number
hitbox.width: number
hitbox.height: number

Note: Use it only for bodies who need collision resolution.

Example (using LÖVE):

local lunar = require 'lunar'

function love.load()
	player = lunar.hitbox:new(0, 12, 32, 64) --x, y, width, height
end

2. Create a Tile

lunar.tile:new(x, y, size)

x: number
y: number
size: number

Returns:
tile: instance

Instance attributes:
tile.x: number
tile.y: number
tile.s: number

Note: Use it for scenario and other things.

Example (using LÖVE):

local lunar = require 'lunar'

function love.load()
	player = lunar.hitbox:new(0, 0, 32, 64)
	tile = lunar.tile:new(150, 150, 32) --x, y, tile size
end

3. Solve collisions

hitbox:solveCollisions(tile)

tile: instance

Returns
collisions: table

Table entries:
collisions.top: boolean
collisions.bottom: boolean
collisions.left: boolean
collisions.right boolean
collisions.topLeft: boolean
collisions.topRight: boolean
collisions.bottomLeft: boolean
collisions.bottomRight: boolean

A collision entry will be true when a collision between hitbox and tile is detected. When it resolutes, it will be false.

Note: top-left and top-right collisions are treated like top collisions by default. Bottom-left and bottom-right collisions are processed like bottom collisions.

Example (using LÖVE):

local lunar = require 'lunar'

function love.load()
	player = lunar.hitbox:new(0, 0, 32, 64)
	tile = lunar.tile:new(150, 150, 32)
	speed = 0
	collision = {}
end

function love.update(dt)
	speed = 150 * dt
	if love.keyboard.isDown("up")    then player.y = player.y - speed end
	if love.keyboard.isDown("down")  then player.y = player.y + speed end
	if love.keyboard.isDown("left")  then player.x = player.x - speed end
	if love.keyboard.isDown("right") then player.x = player.x + speed end
	--Solving all collisions between 'player' and 'tile', and checking the collision entries
	collision = player:solveCollision(tile)
end

function love.draw()
	love.graphics.rectangle('fill', player.x, player.y, player.w, player.h)
	love.graphics.rectangle('line', tile.x, tile.y, tile.s, tile.s)
	-- When a collision occur, an entry below will be true
	love.graphics.print("Top collision: "..tostring(collision.top), 0, 0)
	love.graphics.print("Bottom collision: "..tostring(collision.bottom), 0, 20)
	love.graphics.print("Left collision: "..tostring(collision.left), 0, 40)
	love.graphics.print("Right collision: "..tostring(collision.right), 0, 60)
	love.graphics.print("Top left collision: "..tostring(collision.topLeft), 0, 80)
	love.graphics.print("Top right collision: "..tostring(collision.topRight), 0, 100)
	love.graphics.print("Bottom left collision: "..tostring(collision.bottomLeft), 0, 120)
	love.graphics.print("Bottom right collision: "..tostring(collision.bottomRight), 0, 140)
end

How it works

Coming soon.