Portal rendering

<h2 id="antiportals">Antiportals</h2>

<p>In <a href="/facts/Computer-generated_imagery/ThJ2gh1X">computer-generated imagery</a> and real-time <a href="/facts/3D_computer_graphics/zlWW6eaF">3D computer graphics</a>, antiportal rendering is a way to reduce overdraw (the <a href="/facts/Rendering_(computer_graphics)/YYxfnmAq">rendering</a> of detail which will not be in the final image), and in this way to optimize draw speed. Antiportals are the inverse of portals.
</p><p>An antiportal (or occluder) works by defining a <a href="/facts/Plane_(geometry)/tAUtRFcn">plane</a> or <a href="/facts/Volume/aeAXCBUd">volume</a> which can <i>never</i> be seen through, normally by placing it within an <a href="/facts/Opacity_(optics)/l90q0sAV">opaque</a> object. The renderer uses this to quickly calculate which objects/faces/vertices lie behind the antiportal, and so are out of line of sight, so do not need to be rendered.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
</p><p>Many <a href="/facts/Video_game/vmTdNASJ">video games</a> and 3D graphics programs use this technique for speed rendering. <i><a href="/facts/Unreal_Tournament_2004/GoAUMnwL">Unreal Tournament 2004</a></i>, among many other games, uses this technique.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Binary_space_partitioning/sn9MhTSB">Binary space partitioning</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="http://www.flipcode.com/archives/Building_a_3D_Portal_Engine-Issue_01_Introduction.shtml">Building a 3D Portal Engine</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>David Abramson; Alexander V. Bogdanov; Jack J. Dongarra; Albert Y. Zomaya; Yuriy E. Gorbachev (2003). International Conference Melbourne, Australia and St. Petersburg, Russia June 2–4, 2003 Proceedings, Part I. Computational Science — ICCS 2003. Springer Berlin Heidelberg. p. 915. ISBN 9783540448600. <a href="9783540448600" target="_blank">9783540448600</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Peter Walsh (2010). Advanced 3D Game Programming with DirectX 10.0. Jones & Bartlett Learning. pp. 490–511. ISBN 9781449612764. <a href="9781449612764" target="_blank">9781449612764</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>André LaMothe (2003). Tricks of the 3D Game Programming Gurus: Advanced 3D Graphics and Rasterization. Sams Publishing. p. 1408. ISBN 9780672318351. <a href="9780672318351" target="_blank">9780672318351</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Baldeve Paunoo; Daut Daman (2004). Dynamic Scene Occlusion Culling in Architectural Scenes (PDF) (Master of Science (Computer Science) thesis). Universiti Teknologi Malaysia. <a href="http://gmm.fsksm.utm.my/~cogramm/cgi-bin/2004/upload_files/full_paper_backup/077672.pdf" target="_blank">http://gmm.fsksm.utm.my/~cogramm/cgi-bin/2004/upload_files/full_paper_backup/077672.pdf</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Daniel Sanchez-crespo (2004). Core Techniques and Algorithms in Game Programming. New Riders Press. p. 372. ISBN 9780131020092. <a href="9780131020092" target="_blank">9780131020092</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Byrne, Edward (2005). Game Level Design. Cengage Learning. p. 231. ISBN 1-58450-369-6. <a href="1-58450-369-6" target="_blank">1-58450-369-6</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Byrne, Edward (2005). Game Level Design. Cengage Learning. p. 231. ISBN 1-58450-369-6. <a href="1-58450-369-6" target="_blank">1-58450-369-6</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
</ol>

Portal rendering open-in-new

Portal rendering