title: openGL simple 2d light
body: <p>I am making a simple pixel top-down game. And I want to add some simple lights there, but I don't know what the best way to do that. This image is an example of light what I want to realise. <br>
  <a href="https://imgur.com/a/PpYiR" rel="nofollow noreferrer">http://imgur.com/a/PpYiR</a> <br>
  When I googled that task, I saw only solutions for that kind of light.<br>
  <a href="https://www.youtube.com/watch?v=mVlYsGOkkyM" rel="nofollow noreferrer">https://www.youtube.com/watch?v=mVlYsGOkkyM</a> <br>
  But I need to increase a brightness of the texture part when the light source is near. How can I do this if I am using textures with <code>GL_QUADS</code> without UV?</p>