jtBaseApp/node_modules/@cesium/engine/Source/Shaders/Builtin/Functions/approximateSphericalCoordinates.glsl

/**
 * Approximately computes spherical coordinates given a normal.
 * Uses approximate inverse trigonometry for speed and consistency,
 * since inverse trigonometry can differ from vendor-to-vendor and when compared with the CPU.
 *
 * @name czm_approximateSphericalCoordinates
 * @glslFunction
 *
 * @param {vec3} normal arbitrary-length normal.
 *
 * @returns {vec2} Approximate latitude and longitude spherical coordinates.
 */
vec2 czm_approximateSphericalCoordinates(vec3 normal) {
    // Project into plane with vertical for latitude
    float latitudeApproximation = czm_fastApproximateAtan(sqrt(normal.x * normal.x + normal.y * normal.y), normal.z);
    float longitudeApproximation = czm_fastApproximateAtan(normal.x, normal.y);
    return vec2(latitudeApproximation, longitudeApproximation);
}