Lua script (>=5.1) to convert a GLSL shader into a C string.

formatShader.lua

local function formatString(inputString)

    local outputString = ""

    for line in inputString:gmatch("[^\r\n]+") do

        if line:match("%S") then                                            -- Check if row is empty

            local formattedLine = line:gsub("^%s*", "")                     -- Remove spaces before the first character of the line

            if not formattedLine:match("^%s*//") then                       -- Check if the line is a comment

                local codeLine = formattedLine:gsub("%s*//.*$", "")         -- Delete end of line comment
                codeLine = codeLine:gsub("^", '"')                          -- Add double quotes (") at the beginning of the line

                if line:match("^%s*#") then
                    codeLine = codeLine .. '\\n"\n'                         -- Add "\n" at the end of the line if necessary
                else
                    codeLine = codeLine .. '"\n'                            -- Otherwise, add only a double quote
                end

                outputString = outputString .. codeLine                     -- Append the formatted line to the output string

            end
        end
    end

    return outputString

end

local function main(...)

    local path = select(1, ...)
    local file = assert(io.open(path, "rb"), ("Error: File not found [%s]"):format(path))

    local formattedString = formatString(file:read("*all"))

    file:close()

    print(formattedString)

end

main(...)

input.frag

#version 330 core
#define UNUSED_MACRO 0

uniform vec3 lightPosition;
in vec3 vertexPosition;
out vec4 fragColor;

// GLSL COMMENT

void main() {
    vec3 lightDirection = normalize(lightPosition - vertexPosition);    // LINE 1
    float intensity = dot(vec3(0.0, 1.0, 0.0), lightDirection);         // LINE 2
    fragColor = vec4(intensity, intensity, intensity, 1.0);             // LINE 3
}

output.c

"#version 330 core\n"
"#define UNUSED_MACRO 0\n"
"uniform vec3 lightPosition;"
"in vec3 vertexPosition;"
"out vec4 fragColor;"
"void main() {"
"vec3 lightDirection = normalize(lightPosition - vertexPosition);"
"float intensity = dot(vec3(0.0, 1.0, 0.0), lightDirection);"
"fragColor = vec4(intensity, intensity, intensity, 1.0);"
"}"