GLSL的预处理器都有哪些规定？

There is a preprocessor that processes the source strings as part of the compilation process. Except as noted below, it behaves as the C++ standard preprocessor (see “Normative References”).

有一个预处理器preprocessor，它参与GLSL代码的编译过程。除下文所述外，此preprocessor与C++预处理器的规定相同。