# CMake script file to process a GLSL source file, so it can be included
# in C array and compiled in to an application.

# number of input files
list( LENGTH inputFiles shadersNumber ) 

# check if GLSL source files were updated since the last time
set( update "FALSE" )
foreach( inputFile ${inputFiles} )
    if( ${inputFile} IS_NEWER_THAN ${outputFile} )
        set( update "TRUE" )
    endif( ${inputFile} IS_NEWER_THAN ${outputFile} )
endforeach( inputFile ${inputFiles} )

if( NOT update )
    message( "Headers are up-to-date" )
    return()
endif( NOT update )

# write header
file( WRITE ${outputFile} "// Do not edit this file, it is autogenerated by CMake.

#ifndef SHADER_SRC_H
#define SHADER_SRC_H

const unsigned int shaders_number = ${shadersNumber};
const char* shaders_src[] = 
{\n" )

foreach( inputFile ${inputFiles} )
    # put the input file name into the output file
    file( APPEND ${outputFile} "\n// ${inputFile}" )

    # process the input file
    file( READ ${inputFile} contents )

    # remove /* */ comments
    string( REGEX REPLACE "/\\*.*\\*/" "" contents "${contents}" )
    # remove // comments
    string( REGEX REPLACE "//[^\n]*" "" contents "${contents}" )
    # remove whitespaces at the beginning of each line
    string( REGEX REPLACE "\n([\t ])*" "\n" contents "${contents}" )
    # remove unnecessary spaces
    string( REGEX REPLACE " *([\\*/+&\\|,=<>\(\)]) *" "\\1" contents "${contents}" )
    # remove empty lines & wrap every line in "" and add '\n' at the end of each line	
    string( REGEX REPLACE "\n+" "\\\\n\"\n\"" contents "${contents}" )
    # remove unnecessary " & \n from the beginning and the end of contents
    string( REGEX REPLACE "^\\\\n\"" "" contents "${contents}" )
    string( REGEX REPLACE "\"$" "," contents "${contents}" )

    file( APPEND ${outputFile} "${contents}" )
endforeach( inputFile ${inputFiles} )

# write footer
file( APPEND ${outputFile} "};
#endif /* SHADER_SRC_H */" )