function getLightData( light ) {

	uniformsLib = uniformsLib || new WeakMap();

	let uniforms = uniformsLib.get( light );

	if ( uniforms === undefined ) uniformsLib.set( light, uniforms = {} );

	return uniforms;

}
Stores in an atomic variable the bitwise XOR of its value with a parameter.

@tsl
@function
@param {Node} pointerNode - An atomic variable or element of an atomic buffer.
@param {Node} valueNode - The value that mutates the atomic variable.
@returns {AtomicFunctionNode}