starling-framework/lib/_gen/starling/animation/BezierEasing.js

A fast, productive library for 2D cross-platform development.

// Class: starling.animation.BezierEasing

var $global = typeof window != "undefined" ? window : typeof global != "undefined" ? global : typeof self != "undefined" ? self : this

$global.Object.defineProperty(exports, "__esModule", {value: true});

var __map_reserved = {};

// Imports

var $hxClasses = require("./../../hxClasses_stub").default;
var $import = require("./../../import_stub").default;
function js__$Boot_HaxeError() {return require("./../../js/_Boot/HaxeError");}
function openfl_errors_ArgumentError() {return $import(require("openfl/errors/ArgumentError"));}
function _$UInt_UInt_$Impl_$() {return require("./../../_UInt/UInt_Impl_");}

// Constructor

var BezierEasing = function(){}

// Meta

BezierEasing.__name__ = ["starling","animation","BezierEasing"];
BezierEasing.prototype = {
	
};
BezierEasing.prototype.__class__ = BezierEasing.prototype.constructor = $hxClasses["starling.animation.BezierEasing"] = BezierEasing;

// Init



// Statics

BezierEasing.create = function(x1,y1,x2,y2) {
	if(x1 < 0 || x1 > 1 || x2 < 0 || x2 > 1) {
		throw new (js__$Boot_HaxeError().default)(new (openfl_errors_ArgumentError().default)("x values must be in range [0, 1]"));
	}
	if(x1 == y1 && x2 == y2) {
		return BezierEasing.linearEasing;
	}
	var sampleValues = [];
	var _g = 0;
	while(_g < 11) {
		var i = _g++;
		var tmp = BezierEasing.calcBezier(i * BezierEasing.SAMPLE_STEP_SIZE,x1,x2);
		sampleValues[i] = tmp;
	}
	var getTForX = function(x) {
		var intervalStart = 0.0;
		var currentSample = 1;
		var lastSample = 10;
		while(currentSample != lastSample && sampleValues[currentSample] <= x) {
			intervalStart += BezierEasing.SAMPLE_STEP_SIZE;
			++currentSample;
		}
		--currentSample;
		var dist = (x - sampleValues[currentSample]) / (sampleValues[currentSample + 1] - sampleValues[currentSample]);
		var guessForT = intervalStart + dist * BezierEasing.SAMPLE_STEP_SIZE;
		var initialSlope = BezierEasing.getSlope(guessForT,x1,x2);
		if(initialSlope >= 0.001) {
			return BezierEasing.newtonRaphsonIterate(x,guessForT,x1,x2);
		} else if(initialSlope == 0.0) {
			return guessForT;
		} else {
			return BezierEasing.binarySubdivide(x,intervalStart,intervalStart + BezierEasing.SAMPLE_STEP_SIZE,x1,x2);
		}
	};
	var bezierEasing = function(ratio) {
		if(ratio == 0) {
			return 0;
		} else if(ratio == 1) {
			return 1;
		} else {
			return BezierEasing.calcBezier(getTForX(ratio),y1,y2);
		}
	};
	return bezierEasing;
}
BezierEasing.calcBezier = function(t,a1,a2) {
	return (((1 - 3 * a2 + 3 * a1) * t + (3 * a2 - 6 * a1)) * t + 3 * a1) * t;
}
BezierEasing.getSlope = function(t,a1,a2) {
	return 3 * (1 - 3 * a2 + 3 * a1) * t * t + 2 * (3 * a2 - 6 * a1) * t + 3 * a1;
}
BezierEasing.binarySubdivide = function(ratio,a,b,x1,x2) {
	var currentX;
	var t;
	var i = 0;
	while(true) {
		t = a + (b - a) / 2;
		currentX = BezierEasing.calcBezier(t,x1,x2) - ratio;
		if(currentX > 0) {
			b = t;
		} else {
			a = t;
		}
		var tmp;
		if(Math.abs(currentX) > 0.0000001) {
			++i;
			tmp = (_$UInt_UInt_$Impl_$().default).gt(10,i);
		} else {
			tmp = false;
		}
		if(!tmp) {
			break;
		}
	}
	return t;
}
BezierEasing.newtonRaphsonIterate = function(x,t,x1,x2) {
	var _g = 0;
	while(_g < 4) {
		var i = _g++;
		var currentSlope = BezierEasing.getSlope(t,x1,x2);
		if(currentSlope == 0.0) {
			return t;
		}
		var currentX = BezierEasing.calcBezier(t,x1,x2) - x;
		t -= currentX / currentSlope;
	}
	return t;
}
BezierEasing.linearEasing = function(ratio) {
	return ratio;
}
BezierEasing.NEWTON_ITERATIONS = 4
BezierEasing.NEWTON_MIN_SLOPE = 0.001
BezierEasing.SUBDIVISION_PRECISION = 0.0000001
BezierEasing.SUBDIVISION_MAX_ITERATIONS = 10
BezierEasing.SPLINE_TABLE_SIZE = 11
BezierEasing.SAMPLE_STEP_SIZE = 0.1

// Export

exports.default = BezierEasing;