49 lines
1.1 KiB
JavaScript
49 lines
1.1 KiB
JavaScript
/**************************************************************
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* Ellipse curve
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**************************************************************/
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THREE.EllipseCurve = function ( aX, aY, xRadius, yRadius, aStartAngle, aEndAngle, aClockwise ) {
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this.aX = aX;
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this.aY = aY;
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this.xRadius = xRadius;
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this.yRadius = yRadius;
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this.aStartAngle = aStartAngle;
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this.aEndAngle = aEndAngle;
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this.aClockwise = aClockwise;
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};
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THREE.EllipseCurve.prototype = Object.create( THREE.Curve.prototype );
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THREE.EllipseCurve.prototype.constructor = THREE.EllipseCurve;
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THREE.EllipseCurve.prototype.getPoint = function ( t ) {
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var deltaAngle = this.aEndAngle - this.aStartAngle;
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if ( deltaAngle < 0 ) deltaAngle += Math.PI * 2;
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if ( deltaAngle > Math.PI * 2 ) deltaAngle -= Math.PI * 2;
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var angle;
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if ( this.aClockwise === true ) {
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angle = this.aEndAngle + ( 1 - t ) * ( Math.PI * 2 - deltaAngle );
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} else {
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angle = this.aStartAngle + t * deltaAngle;
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}
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var vector = new THREE.Vector2();
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vector.x = this.aX + this.xRadius * Math.cos( angle );
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vector.y = this.aY + this.yRadius * Math.sin( angle );
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return vector;
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};
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