// This function creates the required texture.
bool Init()
{
    // ...

    g_pFont = TTF_OpenFont("../arial.ttf", 12);
    if(g_pFont == NULL)
        return false;

    // Write text to surface
    g_pText = SDL_DisplayFormatAlpha(TTF_RenderUTF8_Blended(g_pFont, "My first Text!", g_textColor)); //< Doesn't work

    // Note that Solid and Shaded Does work properly if I uncomment them.
    //g_pText = SDL_DisplayFormatAlpha(TTF_RenderUTF8_Solid(g_pFont, "My first Text!", g_textColor));
    //g_pText = SDL_DisplayFormatAlpha(TTF_RenderUTF8_Shaded(g_pFont, "My first Text!", g_textColor, g_bgColor));

    if(g_pText == NULL)
        return false;

    // Prepare the texture for the font
    GLenum textFormat;
    if(g_pText->format->BytesPerPixel == 4)
    {
        // alpha
        if(g_pText->format->Rmask == 0x000000ff)
            textFormat = GL_RGBA;
        else
            textFormat = GL_BGRA_EXT;
    }

    // Create the font's texture
    glGenTextures(1, &g_FontTextureId);
    glBindTexture(GL_TEXTURE_2D, g_FontTextureId);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, g_pText->format->BytesPerPixel, g_pText->w, g_pText->h, 0, textFormat, GL_UNSIGNED_BYTE, g_pText->pixels);

    // ...
}

// this function is called each frame
void DrawText()
{
    SDL_Rect sourceRect;
    sourceRect.x = 0;
    sourceRect.y = 0;
    sourceRect.h = 10;
    sourceRect.w = 173;

    // DestRect is null so the rect is drawn at 0,0
    SDL_BlitSurface(g_pText, &sourceRect, g_pSurfaceDisplay, NULL);

    glBindTexture(GL_TEXTURE_2D, g_FontTextureId);
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_BLEND);
    glBegin( GL_QUADS );

        glTexCoord2f(0.0f, 0.0f);
        glVertex2f(0.0f, 0.0f);

        glTexCoord2f(0.0f, 1.0f);
        glVertex2f(0.0f, 10.0f);

        glTexCoord2f(1.0f, 1.0f);
        glVertex2f(173.0f, 10.0f);

        glTexCoord2f(1.0f, 0.0f);
        glVertex2f(173.0f, 0.0f);

    glEnd();
    glDisable(GL_BLEND);
    glDisable(GL_TEXTURE_2D);
}

glEnable( GL_BLEND );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );

SDL_BlitSurface(g_pText, &sourceRect, g_pSurfaceDisplay, NULL);

g_pText = SDL_DisplayFormatAlpha( TTF_RenderUTF8_Blended(...) );

g_pText = TTF_RenderUTF8_Blended(g_pFont, "My first Text!", g_textColor);