Source code:

#include <GLFW/glfw3.h>
#include <SOIL/SOIL.h>
#include <FTGL/ftgl.h>
#include <stdlib.h>
#include <stdio.h>

FTFont *m_font1, *m_font2;
int width = 800, height = 600;

static void error_callback(int error, const char* description)
{
    fputs(description, stderr);
}
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
}

int main(void)
{
    GLFWwindow* window;
    glfwSetErrorCallback(error_callback);
    if (!glfwInit())
        exit(EXIT_FAILURE);
    window = glfwCreateWindow(800, 600, "Simple example", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        exit(EXIT_FAILURE);
    }
    glfwMakeContextCurrent(window);
    glfwSwapInterval(1);
    glfwSetKeyCallback(window, key_callback);

    glEnable (GL_BLEND);
    glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_TEXTURE_2D);

    // ???????? ????????.
    GLuint tex_2d = SOIL_load_OGL_texture
    (
    "object.png", SOIL_LOAD_AUTO, SOIL_CREATE_NEW_ID,
    SOIL_FLAG_MIPMAPS | SOIL_FLAG_INVERT_Y | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT
    );

    m_font1 = new FTBufferFont("fonts/Linux Biolinum/LinBiolinum_R.otf");
    m_font2 = new FTBufferFont("fonts/Linux Biolinum/LinBiolinum_R.otf");
    if (m_font1->Error()) return -1;
    if (m_font2->Error()) return -1;
    m_font1->FaceSize(20);
    m_font2->FaceSize(16);

    glClearColor(0.4, 0.5, 0.6, 1.0);


    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.0, width, 0.0, height, 1, -1);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    while (!glfwWindowShouldClose(window))
    {

        glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

        glTranslatef(0.1, 0.1, 0.0);

        glColor3f(1.0f, 1.0f, 1.0f);
        glBindTexture(GL_TEXTURE_2D, tex_2d);
        glBegin(GL_QUADS);
        glTexCoord2f (0.0f, 0.0f); glVertex3f(200.0, 200.0, 0);
        glTexCoord2f (1.0f, 0.0f); glVertex3f(500.0, 200.0, 0);
        glTexCoord2f (1.0f, 1.0f); glVertex3f(500.0, 500.0, 0);
        glTexCoord2f (0.0f, 1.0f); glVertex3f(200.0, 500.0, 0);
        glEnd();

        glColor3f(1.0f, 1.0f, 1.0f);
        for (int i = 0; i < 1; ++i)
          m_font1->Render("Testing FTGL", -1, FTPoint(50, 50, 0));

        glfwSwapBuffers(window);
        glfwPollEvents();
    }
    glfwDestroyWindow(window);
    glfwTerminate();
    exit(EXIT_SUCCESS);
}

The text in screenshot 1 looks good. (The program is run on the graphics card Radeon HD 7870.)

The text in screenshot 1 looks bad. (The program is run on the graphics card Geforce2 MX 100 / 200.)

What needs to be fixed?