130 lines
2.7 KiB
JavaScript
130 lines
2.7 KiB
JavaScript
|
'use strict';
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the length of a vector
|
||
|
|
*
|
||
|
|
* @param {Vector}
|
||
|
|
* @return {Float}
|
||
|
|
*/
|
||
|
|
function vectorLength(v) {
|
||
|
|
return Math.sqrt( Math.pow(v.x, 2) + Math.pow(v.y, 2) );
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports.vectorLength = vectorLength;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Calculates the angle between a line a the yAxis
|
||
|
|
*
|
||
|
|
* @param {Array}
|
||
|
|
* @return {Float}
|
||
|
|
*/
|
||
|
|
function getAngle(line) {
|
||
|
|
// return value is between 0, 180 and -180, -0
|
||
|
|
// @janstuemmel: maybe replace return a/b with b/a
|
||
|
|
return Math.atan( (line[1].y - line[0].y) / (line[1].x - line[0].x) );
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports.getAngle = getAngle;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Rotates a vector by a given angle
|
||
|
|
*
|
||
|
|
* @param {Vector}
|
||
|
|
* @param {Float} Angle in radians
|
||
|
|
* @return {Vector}
|
||
|
|
*/
|
||
|
|
function rotateVector(vector, angle) {
|
||
|
|
return (!angle) ? vector : {
|
||
|
|
x: Math.cos(angle) * vector.x - Math.sin(angle) * vector.y,
|
||
|
|
y: Math.sin(angle) * vector.x + Math.cos(angle) * vector.y
|
||
|
|
};
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports.rotateVector = rotateVector;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Solves a 2D equation system
|
||
|
|
* a + r*b = c, where a,b,c are 2D vectors
|
||
|
|
*
|
||
|
|
* @param {Vector}
|
||
|
|
* @param {Vector}
|
||
|
|
* @param {Vector}
|
||
|
|
* @return {Float}
|
||
|
|
*/
|
||
|
|
function solveLambaSystem(a, b, c) {
|
||
|
|
|
||
|
|
// the 2d system
|
||
|
|
var system = [
|
||
|
|
{ n: a[0] - c[0], lambda: b[0] },
|
||
|
|
{ n: a[1] - c[1], lambda: b[1] }
|
||
|
|
];
|
||
|
|
|
||
|
|
// solve
|
||
|
|
var n = system[0].n * b[0] + system[1].n * b[1],
|
||
|
|
l = system[0].lambda * b[0] + system[1].lambda * b[1];
|
||
|
|
|
||
|
|
return -n/l;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Position of perpendicular foot
|
||
|
|
*
|
||
|
|
* @param {Point}
|
||
|
|
* @param [ {Point}, {Point} ] line defined throug two points
|
||
|
|
* @return {Point} the perpendicular foot position
|
||
|
|
*/
|
||
|
|
function perpendicularFoot(point, line) {
|
||
|
|
|
||
|
|
var a = line[0], b = line[1];
|
||
|
|
|
||
|
|
// relative position of b from a
|
||
|
|
var bd = { x: b.x - a.x, y: b.y - a.y };
|
||
|
|
|
||
|
|
// solve equation system to the parametrized vectors param real value
|
||
|
|
var r = solveLambaSystem( [ a.x, a.y ], [ bd.x, bd.y ], [ point.x, point.y ] );
|
||
|
|
|
||
|
|
return { x: a.x + r*bd.x, y: a.y + r*bd.y };
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports.perpendicularFoot = perpendicularFoot;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Calculates the distance between a point and a line
|
||
|
|
*
|
||
|
|
* @param {Point}
|
||
|
|
* @param [ {Point}, {Point} ] line defined throug two points
|
||
|
|
* @return {Float} distance
|
||
|
|
*/
|
||
|
|
function getDistancePointLine(point, line) {
|
||
|
|
|
||
|
|
var pfPoint = perpendicularFoot(point, line);
|
||
|
|
|
||
|
|
// distance vector
|
||
|
|
var connectionVector = {
|
||
|
|
x: pfPoint.x - point.x,
|
||
|
|
y: pfPoint.y - point.y
|
||
|
|
};
|
||
|
|
|
||
|
|
return vectorLength(connectionVector);
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports.getDistancePointLine = getDistancePointLine;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Calculates the distance between two points
|
||
|
|
*
|
||
|
|
* @param {Point}
|
||
|
|
* @param {Point}
|
||
|
|
* @return {Float} distance
|
||
|
|
*/
|
||
|
|
function getDistancePointPoint(point1, point2) {
|
||
|
|
|
||
|
|
return vectorLength({
|
||
|
|
x: point1.x - point2.x,
|
||
|
|
y: point1.y - point2.y
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports.getDistancePointPoint = getDistancePointPoint;
|