// luma.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
/**
 * Calculate WebGL 64 bit float
 * @param a  - the input float number
 * @param out - the output array. If not supplied, a new array is created.
 * @param startIndex - the index in the output array to fill from. Default 0.
 * @returns - the fp64 representation of the input number
 */
export function fp64ify(a, out = [], startIndex = 0) {
    const hiPart = Math.fround(a);
    const loPart = a - hiPart;
    out[startIndex] = hiPart;
    out[startIndex + 1] = loPart;
    return out;
}
/**
 * Calculate the low part of a WebGL 64 bit float
 * @param a the input float number
 * @returns the lower 32 bit of the number
 */
export function fp64LowPart(a) {
    return a - Math.fround(a);
}
/**
 * Calculate WebGL 64 bit matrix (transposed "Float64Array")
 * @param matrix  the input matrix
 * @returns the fp64 representation of the input matrix
 */
export function fp64ifyMatrix4(matrix) {
    // Transpose the projection matrix to column major for GLSL.
    const matrixFP64 = new Float32Array(32);
    for (let i = 0; i < 4; ++i) {
        for (let j = 0; j < 4; ++j) {
            const index = i * 4 + j;
            fp64ify(matrix[j * 4 + i], matrixFP64, index * 2);
        }
    }
    return matrixFP64;
}