const { sin, cos } = require('../utils/trigonometry')
/**
* Rotates a matrix by the given angle around the X axis.
*
* @param {mat4} out - receiving matrix
* @param {mat4} matrix - matrix to rotate
* @param {Number} radians - angle to rotate the matrix by
* @returns {mat4} out
* @alias module:modeling/maths/mat4.rotateX
*/
const rotateX = (out, matrix, radians) => {
const s = sin(radians)
const c = cos(radians)
const a10 = matrix[4]
const a11 = matrix[5]
const a12 = matrix[6]
const a13 = matrix[7]
const a20 = matrix[8]
const a21 = matrix[9]
const a22 = matrix[10]
const a23 = matrix[11]
if (matrix !== out) { // If the source and destination differ, copy the unchanged rows
out[0] = matrix[0]
out[1] = matrix[1]
out[2] = matrix[2]
out[3] = matrix[3]
out[12] = matrix[12]
out[13] = matrix[13]
out[14] = matrix[14]
out[15] = matrix[15]
}
// Perform axis-specific matrix multiplication
out[4] = a10 * c + a20 * s
out[5] = a11 * c + a21 * s
out[6] = a12 * c + a22 * s
out[7] = a13 * c + a23 * s
out[8] = a20 * c - a10 * s
out[9] = a21 * c - a11 * s
out[10] = a22 * c - a12 * s
out[11] = a23 * c - a13 * s
return out
}
module.exports = rotateX