libtween

libtween copied to clipboard

libtween 0.2

*** What is libtween?

libtween is a tweening engine written in C.

It is a port of "Javascript Tweening Engine" by @sole and others at:

https://github.com/sole/tween.js

*** How do I build the source?

./configure make sudo make install

*** Usage

To use libtween

1. create callback function that updates properties of an object
2. create a Tween_Engine
3. create Tween_Props structures that represents the start and to properties of an object
4. create a Tween with Tween_Engine, Tween_Props, duration, easing, and callback parameters
5. start the Tween
6. update the Tween_Engine in an animation loop
7. destroy Tween
8. destroy Tween_Engine

RECT gRect;

void update(Tween* tween) { gRect.x = tween->props->x; gRect.y = tween->props->y; }

. . .

  Tween_Engine* engine = Tween_CreateEngine();
  Tween_Props props = Tween_MakeProps(x1, y1, w1, h1, rot1);
  Tween_Props toProps = Tween_MakeProps(x2, y2, w2, h2, rot2);
  Tween* tween = Tween_CreateTween(engine, &props, &toProps, duration,
     TWEEN_EASING_ELASTIC_IN_OUT, update, NULL);
     Tween_Start(engine, SDL_GetTicks()); 

  while(!terminate) {
     Tween_UpdateEngine(engine, SDL_GetTicks());
  
     .
     .
  }

  Tween_Destroy(tween);
  Tween_Engine(engine);

*** Examples

Currently libtween comes with two examples, hello_world and bars.

These examples closely match the tween.js examples at:

http://sole.github.io/tween.js/examples/00_hello_world.html http://sole.github.io/tween.js/examples/01_bars.html

To run the examples, you must have SDL2 installed on your system

*** Differences from tween.js

libtween is a thorough port of tween.js with a few differences. Tween_Props structures are used simulate javascript properties and contains the following variables:

x, y, width, height, rotation, r, g, b, a

Tween_Props currently has no concept of arrays. Because of this, the interpolation features of tween.js have not been ported.