Modern OpenGL SDL text rendering

frag.glsl

#version 330
in vec2 texCoord;
in vec4 fragColor;

out vec3 finalColor;

uniform sampler2D myTextureSampler;
void main() {
    finalColor = texture( myTextureSampler, texCoord ).rgb;
}

loadFont.cpp

    //Initialise TTF
    if( TTF_Init() == -1 )
        throw std::runtime_error("SDL_TTF failed to initialise.");
    
    //Load the texture
    font = TTF_OpenFont( filePath.c_str(), 12 );
    if(!font)
        throw std::runtime_error("Couldn't load: "+ filePath);
    
   	TTF_SetFontStyle(font, TTF_STYLE_NORMAL);
    
    surface = TTF_RenderUTF8_Blended(font, "Hello", this->textColor);
    Uint8 colors = surface->format->BytesPerPixel;
    int texture_format;
    if (colors == 4) {   // alpha
        if (surface->format->Rmask == 0x000000ff)
            texture_format = GL_RGBA;
        else
            texture_format = GL_BGRA;
    } else {             // no alpha
        if (surface->format->Rmask == 0x000000ff)
            texture_format = GL_RGB;
        else
            texture_format = GL_BGR;
    }
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    
    glTexImage2D(GL_TEXTURE_2D, 0, colors, surface->w, surface->h, 0,
                 texture_format, GL_UNSIGNED_BYTE, surface->pixels);
    SDL_FreeSurface(surface);

vert.glsl

#version 330

in vec3 vert;
in vec4 color;
in vec2 texcoord;

out vec4 fragColor;
out vec2 texCoord;

void main() {
    fragColor = color;
    gl_Position = vec4(vert, 1);
    texCoord = texcoord;
}