title: How to scale and tranlate each component diplayed in opengl output screen instead of applying Arthamatics on each glVertex2f
body: <p>I am new begnieer in opengl.I have searched on internet way to <em>collectively</em> apply scaling and translation to each element of opengl instead on applying arthamtics on each vertex (multiplication with 3.2 and substraction by 1300) like this but did not found any helping material</p>
  <pre><code> glVertex2f(screenx * 3.2 - 1300, screeny * 3.2 - 1300);
   glVertex2f(screenx1 * 3.2 - 1300, screeny1 * 3.2 - 1300);
  </code></pre>
  <p>I am tired using this arthmatics with each vertix for entire project. Is here some OpenGL function or programming convenient way which can reduce the multiple type of same arthamtics on each vertex.</p>