Minetest-WorldEditAdditions/rotate.js

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#!/usr/bin/env node
/**
* Rotate a given point around an origin point in 3d space.
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* NOTE: This function is not as intuitive as it sounds.
* A whiteboard and a head for mathematics is recommended before using this
* function.
* @source GitHub Copilot
* @warning Not completely tested! Pending a thorough evaluation.
* @param {Vector3} origin The origin point to rotate around
* @param {Vector3} point The point to rotate.
* @param {Number} x Rotate this much around the X axis (yz plane), in radians.
* @param {Number} y Rotate this much around the Y axis (xz plane), in radians.
* @param {Number} z Rotate this much around the Z axis (xy plane), in radians.
* @return {Vector3} The rotated point.
*/
function rotate_point_3d(origin, point, x, y, z)
{
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point = [...point];
point[0] = point[0] - origin[0];
point[1] = point[1] - origin[1];
point[2] = point[2] - origin[2];
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// rotate around x
var x1 = point[0];
var y1 = point[1] * Math.cos(x) - point[2] * Math.sin(x);
var z1 = point[1] * Math.sin(x) + point[2] * Math.cos(x);
// rotate around y
var x2 = x1 * Math.cos(y) + z1 * Math.sin(y);
var y2 = y1;
var z2 = -x1 * Math.sin(y) + z1 * Math.cos(y);
// rotate around z
var x3 = x2 * Math.cos(z) - y2 * Math.sin(z);
var y3 = x2 * Math.sin(z) + y2 * Math.cos(z);
var z3 = z2;
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return [x3+origin[0], y3+origin[1], z3+origin[2]];
}
function deg_to_rad(deg)
{
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return deg * Math.PI / 180;
}
function point_to_string(point, decimal_places=3)
{
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return "(x " + point[0].toFixed(decimal_places) + ", y " + point[1].toFixed(decimal_places) + ", z " + point[2].toFixed(decimal_places) + ")";
}
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function do_test(origin, point, ...args) {
const result = rotate_point_3d(origin, point, ...args);
console.log(`ORIGIN`, point_to_string(origin), `\tPOINT`, point_to_string(point), `\tRESULT`, point_to_string(result));
}
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do_test(
[1, 0, 0],
[5, 0, 0],
deg_to_rad(0), // rotate around x axis = yz plane
deg_to_rad(0), // rotate around y axis = xz plane
deg_to_rad(180) // rotate around z axis = xy plane
);
do_test(
[1, 0, 0],
[0, 1, 0],
deg_to_rad(0), // rotate around x axis = yz plane
deg_to_rad(0), // rotate around y axis = xz plane
deg_to_rad(180) // rotate around z axis = xy plane
);
do_test(
[10, 100, 0],
[0, 0, 0],
deg_to_rad(0), // rotate around x axis = yz plane
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deg_to_rad(0), // rotate around y axis = xz plane
deg_to_rad(180) // rotate around z axis = xy plane
);