/**
 * A built-in GLSL floating-point constant for <code>Math.PI</code>.
 *
 * @alias czm_pi
 * @glslConstant
 *
 * @see CesiumMath.PI
 *
 * @example
 * // GLSL declaration
 * const float czm_pi = ...;
 *
 * // Example
 * float twoPi = 2.0 * czm_pi;
 */
const float czm_pi = 3.141592653589793;