title: OpenGL why does repeating texture over same amount of fragments may cost performance?
body: <p>I have a quad of unitary size rendered with seamless texture and with texture repetition enabled.</p>
  
  <p>For the texture coordinates I get it from the position.
  So I can artificially raise the texture resolution by multiplying the texture coordinates by a factor of N, which will make the texture repeat over the quad N*N times.</p>
  
  <p>In my code my texture is a normal map and there is specular light calculation with it in fragment shader. And I noticed more I multiply the texture coordinates more my performance drops, however it seems the performance drop is constant after a certain value (no difference between N = 1024 and N = 10240 for example)</p>
  
  <p>What I do not understand is that the quad size stays the same, the texture size is the same, why does multiplying texture coordinates cost me performance over the same amount of fragments ?</p>