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