This is a lua port of the Robert Penner's equations for easing. You can find much more information about it on his web site.
This library was based off:
However, only the easing functions are included, and not any kind of tweening helpers.
Requiring the easing library returns a table which contains all the different functions.
local easingFunctions = require("easing")
outInBounce = easingFunctions.outInBounce
-- All easing functions take these parameters:
--
-- t = time should go from 0 to duration
-- b = begin value of the property being ease.
-- c = change ending value of the property - beginning value of the property
-- d = duration
-- Some functions allow additional modifiers, like the elastic functions
-- which also can receive an amplitud and a period parameters (defaults
-- are included)
beginVal = 0
endVal = 1
change = endVal - beginVal
duration = 1
print(outInBounce(0 , beginVal, change, duration)) --> 0
print(outInBounce(duration / 4 , beginVal, change, duration)) --> 0.3828125
print(outInBounce(duration / 2 , beginVal, change, duration)) --> 0.5
print(outInBounce(duration / 3/4, beginVal, change, duration)) --> 0.10503472222222
print(outInBounce(duration , beginVal, change, duration)) --> 1
There is a plain lua example and an interactive one based on the LÖVE game library. To run the examples you'll need to get the engine from http://love2d.org. Once you have the love executable, move into the examples/love directory and run "love ."
To run the tests you'll need telescope. From the library's root directory, run:
▸ tsc tests/easing_tests.lua
80 tests 80 passed 80 assertions 0 failed 0 errors 0 unassertive 0 pending
Copy the documentation from the tweener source and convert it to luadoc.
Like the tweener library, easing is licensed under the MIT license.
- Tweener authors
- Yuichi Tateno
- Emmanuel Oga
- kikito (Enrique García) (#2)