title: Understaing shadow acne better
body: <p>I'm currently learning about shadow mapping from <a href="https://learnopengl.com/Advanced-Lighting/Shadows/Shadow-Mapping" rel="nofollow noreferrer">here</a>.</p>
  
  <p>I'm trying to figure why shadow acne is happening at-all, I've tried looking at every video/resource I found online, some relate the issue to floating point rounding errors, other say it's about the size of the shadow map and if it could be infinitely large then this problem wouldn't occur,<br/>but none of the explanation I've seen connects as to why I see this "trippy line pattern":
  <a href="https://i.stack.imgur.com/jTGp0.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jTGp0.jpg" alt="enter image description here"></a></p>
  
  <p>Some explanations even include some sort of abstract drawing that can visually relate to the phenomenon on screen but really don't explain well the underlying reason this happens:
  <a href="https://i.stack.imgur.com/TStLl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TStLl.png" alt="enter image description here"></a></p>
  
  <p>I've been scratching my head about this looking everywhere for a whole day for a suffice explanation.<br/>I'm basically looking for a new explanation to this phenomenon, hopefully a clear and friendly one.</p>
  
  <p>Also I would like to know after hopefully understanding the <strong>cause</strong> of this, how biasing/face culling helps solve this problem, and how they trade this problem for <strong>peter penning</strong> problem, as I think there's no clear explanation to the why <em>this happens instead of this</em>.</p>