source: other-projects/playing-in-the-street/summer-2013/trunk/Playing-in-the-Street-WPF/Content/Web/mrdoob-three.js-4862f5f/src/extras/curves/QuadraticBezierCurve.js@ 28897

/**************************************************************
 *  Quadratic Bezier curve
 **************************************************************/


THREE.QuadraticBezierCurve = function ( v0, v1, v2 ) {

    this.v0 = v0;
    this.v1 = v1;
    this.v2 = v2;

};

THREE.QuadraticBezierCurve.prototype = Object.create( THREE.Curve.prototype );


THREE.QuadraticBezierCurve.prototype.getPoint = function ( t ) {

    var tx, ty;

    tx = THREE.Shape.Utils.b2( t, this.v0.x, this.v1.x, this.v2.x );
    ty = THREE.Shape.Utils.b2( t, this.v0.y, this.v1.y, this.v2.y );

    return new THREE.Vector2( tx, ty );

};


THREE.QuadraticBezierCurve.prototype.getTangent = function( t ) {

    var tx, ty;

    tx = THREE.Curve.Utils.tangentQuadraticBezier( t, this.v0.x, this.v1.x, this.v2.x );
    ty = THREE.Curve.Utils.tangentQuadraticBezier( t, this.v0.y, this.v1.y, this.v2.y );

    // returns unit vector

    var tangent = new THREE.Vector2( tx, ty );
    tangent.normalize();

    return tangent;

};