A GLSL preprocessor based on the C-Preprocessor library.

Usage

import Preprocessor from '@andrewray/glsl-preprocessor';

const result = new Preprocessor(options).preprocess(src);

Options

This are the defaults options. You can modify them by passing an option object.

var options = {
  // Predefined constants (ex: { "MY_CONST": "42" })
  constants: {},

  // Predefined macros (ex: { "MACRO": "(a,b) a+b" })
  macros: {},

  // End of line character
  newLine: '\n',

  // Escape '//#' & '/*#' comments (see extra/comments)
  commentEscape: true,

  // Empty lines to add between code and included files
  includeSpaces: 0,

  // Limit of empty following lines (0 = no limit)
  emptyLinesLimit: 0,

  // Base path for including files
  basePath: './'
};

Features

Define

// Define a constant
#define MY_CONST 42

// Define a macro
#define SUM(a,b) a + b

Create a constant or a macro.

Undefine

#undef MY_CONST

Delete a constant or a macro.

Condition

#if A + B == 5 && defined(MY_CONST)
  // Do stuff
#elif "MY_CONST2" == "House"
  // Do other stuff
#else
  // Do other stuff
#endif

#ifndef MY_CONST3
  // Do stuff
#endif

C like conditions.
#if condition is evaluated in JS so you must add " between string constants.
Note: #ifdef C and #ifndef C are faster than #if defined(C) and #if !defined(C).

Error

#error This is an error

Stop the compiler and raise the error.

Extra

Compiler constants

__LINE__ // Current line (where this constant is used).
__FILE__ // Current file (where this constant is used).

This constants are predefined by the compiler.

Comments

//# One line comment

/*#

Multi-lines comment

#*/

This comments will be deleted in the compiled file.
Note: options.commentEscape must be true.