title: opengl texture coordinates for full-screen effect
body: <p>how can i create the full-screen effect with a texture image ? 
  till now i do this :</p>
  
  <pre><code>static void Draw(void)
  {
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
      glLoadIdentity();
      glTranslatef(0.0f,0.0f,-5.0f);
      texture[0] = SOIL_load_OGL_texture // load an image file directly as a new OpenGL texture
      (
          "my_img.jpg",
          SOIL_LOAD_AUTO,
          SOIL_CREATE_NEW_ID,
           SOIL_FLAG_INVERT_Y | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT
      );
  
      glBindTexture(GL_TEXTURE_2D, texture[0]);
      glBegin(GL_POLYGON);
  
      glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
      glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
      glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
      glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
  
      glEnd();
      glutSwapBuffers();
  }
  </code></pre>
  
  <p>this code places my image in the top-left position of the screen, but i would like the full-screen texture effect.
  So, How can i accomplish that ?</p>