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:

"\x00\x00\x00\x00\........ \x00\x00\x00\x00"

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

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;
    }
    .
    .
    .