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    <div class="moz-cite-prefix">On 6/25/2013 11:18 AM, Chris Endicott
      wrote:<br>
    </div>
    <blockquote
cite="mid:2E38AD177B18F54E937232AB80A019D10BEDB157@EXCHANGE2.commercial.jagex.network"
      type="cite">
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      <div class="WordSection1">
        <p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Here's
            some benchmarks of our shader compile times in the RuneScape
            engine. RuneScape uses a couple of hundred permutations of
            shader at run time to handle various combinations of
            effects/lighting/shadows and so on. It does this to remove
            control flow statements from the shader source itself, as
            far as possible.</span></p>
      </div>
    </blockquote>
    <br>
    Hm, it sounds like what you really want, for this in particular, is
    a way to cache compiled shaders.  We were thinking of doing this
    under the hood anyway as we can do it transparently by hashing
    source + compiler details (especially when using D3D via ANGLE, by
    caching the bytecode).  That should largely remove this bottleneck
    for you.<br>
    <br>
    The thing with GL context share groups, as soon as you touch
    contexts in a share group from different threads, you flip on all
    sorts of locking/sync primitives in the GL drivers, which results in
    an overall perf hit.  I think you'd get this even if you were to
    only use the other context to compile shaders.  Of course, that
    might not be the case for a D3D-backed GL, but as mobile WebGL is
    increasingly becoming viable, straight GL implementations are going
    to become more common.<br>
    <br>
         - Vlad<br>
    <br>
    <br>
  </body>
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