mirror of
https://github.com/photonstorm/phaser
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20 lines
631 B
JavaScript
20 lines
631 B
JavaScript
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var GetPoint = require('./GetPoint');
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/**
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* Calculate and return the angle, in radians, of the curves tangent based on time.
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*
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* @param {number} [t=0] - The `t` (time) value at which to find the angle. Must be between 0 and 1.
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* @return {number} The angle of the line at the specified `t` time value along the curve. The value is in radians.
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*/
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var GetAngle = function (curve, t)
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{
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if (t === undefined) { t = 0; }
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GetPoint(curve, t - 0.01, curve._temp1);
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GetPoint(curve, t + 0.01, curve._temp2);
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return Math.atan2(curve._temp2.y - curve._temp1.y, curve._temp2.x - curve._temp1.x);
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};
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module.exports = GetAngle;
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