toosoon-utils
Version:
Utility functions & classes
94 lines (93 loc) • 2.65 kB
JavaScript
import { lerp } from '../../maths';
import { Vector2 } from '../geometry';
import Curve from './Curve';
/**
* Utility class for manipulating lines
*
* @exports
* @class LineCurve
* @extends Curve
*/
export default class LineCurve extends Curve {
type = 'LineCurve';
/**
* X-axis coordinate of the start point
*/
x1;
/**
* Y-axis coordinate of the start point
*/
y1;
/**
* X-axis coordinate of the end point
*/
x2;
/**
* Y-axis coordinate of the end point
*/
y2;
/**
* @param {number} x1 X-axis coordinate of the start point
* @param {number} y1 Y-axis coordinate of the start point
* @param {number} x2 X-axis coordinate of the end point
* @param {number} y2 Y-axis coordinate of the end point
*/
constructor(x1, y1, x2, y2) {
super();
this.x1 = x1;
this.y1 = y1;
this.x2 = x2;
this.y2 = y2;
}
/**
* Interpolate a point on this curve
*
* @param {number} t Normalized time value to interpolate
* @returns {Vector2} Interpolated coordinates on this curve
*/
getPoint(t) {
return new Vector2(...LineCurve.interpolate(t, this.x1, this.y1, this.x2, this.y2));
}
/**
* Interpolate a point on this line
*
* @param {number} u Normalized position value to interpolate
* @returns {Vector2} Interpolated coordinates on this line
*/
getPointAt(u) {
return this.getPoint(u);
}
/**
* Compute an unit vector tangent for a given normalized time value
*
* @param {number} t Normalized time value
* @returns {Vector2} Tangent vector
*/
getTangent(t) {
return new Vector2(...Vector2.sub([this.x1, this.y1], [this.x2, this.y2])).normalize();
}
/**
* Compute an unit vector tangent for a given normalized position value
*
* @param {number} u Normalized position value
* @returns {Vector2} Tangent vector
*/
getTangentAt(u) {
return this.getTangent(u);
}
/**
* Interpolate a point on a line
*
* @param {number} t Normalized time value to interpolate
* @param {number} x1 X-axis coordinate of the start point
* @param {number} y1 Y-axis coordinate of the start point
* @param {number} x2 X-axis coordinate of the end point
* @param {number} y2 Y-axis coordinate of the end point
* @returns {Point2} Interpolated coordinates on the line
*/
static interpolate(t, x1, y1, x2, y2) {
const x = lerp(t, x1, x2);
const y = lerp(t, y1, y2);
return [x, y];
}
}