fireball/lib/extras/core/Interpolations.js
2018-12-25 17:29:22 +03:30

82 lines
1.2 KiB
JavaScript

/**
* @author zz85 / http://www.lab4games.net/zz85/blog
*
* Bezier Curves formulas obtained from
* http://en.wikipedia.org/wiki/Bézier_curve
*/
function CatmullRom( t, p0, p1, p2, p3 ) {
var v0 = ( p2 - p0 ) * 0.5;
var v1 = ( p3 - p1 ) * 0.5;
var t2 = t * t;
var t3 = t * t2;
return ( 2 * p1 - 2 * p2 + v0 + v1 ) * t3 + ( - 3 * p1 + 3 * p2 - 2 * v0 - v1 ) * t2 + v0 * t + p1;
}
//
function QuadraticBezierP0( t, p ) {
var k = 1 - t;
return k * k * p;
}
function QuadraticBezierP1( t, p ) {
return 2 * ( 1 - t ) * t * p;
}
function QuadraticBezierP2( t, p ) {
return t * t * p;
}
function QuadraticBezier( t, p0, p1, p2 ) {
return QuadraticBezierP0( t, p0 ) + QuadraticBezierP1( t, p1 ) +
QuadraticBezierP2( t, p2 );
}
//
function CubicBezierP0( t, p ) {
var k = 1 - t;
return k * k * k * p;
}
function CubicBezierP1( t, p ) {
var k = 1 - t;
return 3 * k * k * t * p;
}
function CubicBezierP2( t, p ) {
return 3 * ( 1 - t ) * t * t * p;
}
function CubicBezierP3( t, p ) {
return t * t * t * p;
}
function CubicBezier( t, p0, p1, p2, p3 ) {
return CubicBezierP0( t, p0 ) + CubicBezierP1( t, p1 ) + CubicBezierP2( t, p2 ) +
CubicBezierP3( t, p3 );
}
export { CatmullRom, QuadraticBezier, CubicBezier };