iv>
<div class="line">   <span class="comment">// define the dest_closing and dest_changed methods.</span></div>
<div class="line">   <span class="comment">// these methods are called by jit.gl.render when the</span></div>
<div class="line">   <span class="comment">// destination context closes or changes: for example, when</span></div>
<div class="line">   <span class="comment">// the user moves the window from one monitor to another. Any</span></div>
<div class="line">   <span class="comment">// resources