c++ - GLSL shader compilation debugger results in a flood of the character x00 on the console

Question

I am trying to debug my OpenGL shaders compilation but i'm having some strange output related to null characters I believe, my debugger console is flooded with a lot of x00 characters and I am trying to understand where does it come from and how to get rid of it. This is my function:

void DebugShader(GLuint shader) { //debug shader
    GLint isComp = 0;
    GLint maxLength;
    std::vector<GLchar> errorLog(maxLength); 
    std::string log; 
    glGetShaderiv(shader, GL_COMPILE_STATUS, &isComp); 
    if(isComp!=GL_TRUE) {
        glGetShaderiv(shader,GL_INFO_LOG_LENGTH,&maxLength);
        glGetShaderInfoLog(shader, maxLength, &maxLength,&errorLog[0]);
        std::cout << "Shader compilation Failed." << std::endl;
    }
    for (int i = 0; i<maxLength; i++){
        log.push_back(errorLog.at(i));
        std::cout << log;
    }
    if (isComp==GL_TRUE){
        std::cout << "Shader compilation successful." << std::endl;
        glDeleteShader(shader);
    }
}

This is the output I am getting:

"x00x00x00x00 ........ x00x00x00x00"

If I mess up the shader codes, just to check if the error output is working, I can find the error messages among those characters

question from:https://stackoverflow.com/questions/65891041/glsl-shader-compilation-debugger-results-in-a-flood-of-the-character-x00-on-the

Answer 1

You're using maxLength uninitialized to set the size of the vector errorLog. You need to resize errorLog after initializing maxLength.

The code should be more along the lines of (untested)...

void DebugShader(GLuint shader)
{
    GLint isComp = 0;
    glGetShaderiv(shader, GL_COMPILE_STATUS, &isComp); 
    if(isComp!=GL_TRUE) {
        GLint maxLength;
        glGetShaderiv(shader,GL_INFO_LOG_LENGTH,&maxLength);
        std::vector<GLchar> errorLog(maxLength);
        glGetShaderInfoLog(shader, maxLength, &maxLength,&errorLog[0]);
        std::cout << "Shader compilation Failed." << std::endl;
    }
    .
    .
    .