Add pointerlock.html.md file

[Cocomwana]

Hello,

Added a pointer.hmd.md file but unfortunately could not find a snippet that was simple enough.

Cheers

Done as part as 24PR @codebar

[BPScott]

Hi @Cocomwana, thanks for taking the time to contribute!

I'd like to keep the trend of having code examples on each page. Taking a look at the MDN demo it looks like a minimal demo could be something like (I've not tested this!):

var htmlElem = document.querySelector('html');

htmlElem.requestPointerLock = htmlElem.requestPointerLock ||
           htmlElem.mozRequestPointerLock ||
           htmlElem.webkitRequestPointerLock;

htmlElem.onclick = function() {
  htmlElem.requestPointerLock();
}

// pointer lock event listeners

// Hook pointer lock state change events for different browsers
document.addEventListener('pointerlockchange', lockChangeAlert, false);
document.addEventListener('mozpointerlockchange', lockChangeAlert, false);
document.addEventListener('webkitpointerlockchange', lockChangeAlert, false);

function lockChangeAlert() {
  if(document.pointerLockElement === htmlElem ||
  document.mozPointerLockElement === htmlElem ||
  document.webkitPointerLockElement === htmlElem) {
    console.log('The pointer lock status is now locked');
    document.addEventListener("mousemove", htmlElemLoop, false);
  } else {
    console.log('The pointer lock status is now unlocked');
    document.removeEventListener("mousemove", htmlElemLoop, false);
  }
}

function htmlElemLoop(e) {
  var movementX = e.movementX || e.mozMovementX || e.webkitMovementX || 0;
  var movementY = e.movementY || e.mozMovementY || e.webkitMovementY || 0;

  console.log(movementX, movementY);
}

Could you check if that code works (use http://codepen.io or something to that effect) and add it to the PR (with along with any fixes that need to be made because I fail at copy+pasting code).

[BPScott]

Linking comment, this is a PR for #37