Easing

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Revision as of 10:54, 17 December 2010 by Kayl 712 (talk | contribs)
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Easing functions describe functions that control the way an interpolation between 0 and 1 is done.

The most basic one, linear, is just a linear interpolation at constant speed. Other more advanced easing functions can have acceleration at the beginning, the end or both, or deceleration , or even bouncing or elastic effects.

The naming conventions of the functions below, available in moveObject, interpolateBetween, or getEasingValue as been extracted from http://doc.qt.nokia.com/latest/qeasingcurve.html. Only a subset of those functions is available in MTA since some of them are a bit redundant (only the profile or acceleration/deceleration changes).

Preliminary note

In the functions using easing, there are usually 3 optional parameters. Most functions don't need them at all, the ones needing one or more parameters are listed in the table below. When providing optional parameters, all the parameters before a given parameter must be filled, even if the easing function you intend to use doesn't require such a parameter. In this case, simply use 0 for the parameters you don't need. Examples:

  • "Linear" can used simply with getEasingValue( fProgress, "Linear" )
  • "OutElastic" can define fEasingPeriod and fEasingAmplitude with getEasingValue( fProgress, "OutElastic", 0.3, 1.0 )
  • "InBack" can define fEasingOvershoot, but since it comes after fEasingPeriod and fEasingAmplitude in the order of parameters, 0 must be used for the others with getEasingValue( fProgress, "InBack", 0, 0, 1.7015 )

Easing functions

Easing function (strEasingType) Function profile Can use fEasingPeriod (default 0.3) Can use fEasingAmplitude (default 1.0) Can use fEasingOvershoot(default 1.7015) Comments
Linear
InQuad