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| 2 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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| 3 | <HTML>
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| 4 | <HEAD>
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| 5 | <TITLE>Visibility</TITLE>
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| 6 | <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1">
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| 7 | <META NAME="Generator" CONTENT="NetObjects Fusion 8 für Windows">
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| 8 | <BASE TARGET="_parent">
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| 9 | <LINK REL=STYLESHEET TYPE="text/css" HREF="../html/style.css">
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| 10 | <LINK REL=STYLESHEET TYPE="text/css" HREF="../html/site.css">
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| 11 | <STYLE>
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| 13 | </HEAD>
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| 14 | <BODY NOF="(MB=(DefaultMasterBorder, 121, 49, 171, 0), L=(VisibilityLayout, 860, 700))" TOPMARGIN=0 LEFTMARGIN=0 MARGINWIDTH=0 MARGINHEIGHT=0>
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| 15 | <TABLE BORDER=0 CELLSPACING=0 CELLPADDING=0 WIDTH=860 NOF=LY>
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| 16 | <TR VALIGN=TOP ALIGN=LEFT>
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| 17 | <TD WIDTH=19 HEIGHT=54><IMG SRC="../assets/images/autogen/clearpixel.gif" WIDTH=19 HEIGHT=1 BORDER=0 ALT=""></TD>
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| 18 | <TD WIDTH=7><IMG SRC="../assets/images/autogen/clearpixel.gif" WIDTH=7 HEIGHT=1 BORDER=0 ALT=""></TD>
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| 19 | <TD WIDTH=18><IMG SRC="../assets/images/autogen/clearpixel.gif" WIDTH=18 HEIGHT=1 BORDER=0 ALT=""></TD>
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| 20 | <TD WIDTH=816><IMG SRC="../assets/images/autogen/clearpixel.gif" WIDTH=816 HEIGHT=1 BORDER=0 ALT=""></TD>
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| 21 | </TR>
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| 22 | <TR VALIGN=TOP ALIGN=LEFT>
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| 23 | <TD COLSPAN=2></TD>
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| 24 | <TD COLSPAN=2 WIDTH=834 CLASS="TextObject" STYLE="background-color: rgb(255,255,255);">
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| 25 | <P>In computer graphics, <B>Visibility</B> deals with the problem of rendering faster by rendering only the objects of the scene that can be seen.<BR>Existing solutions along that line employed in modern day 3D/game-engines are mostly based either on <B>Portals</B> or on <B>Quake style PVS</B> (potentially visible set). While these approaches have been successfully employed in commercial products for years, they nonetheless have considerable drawbacks: </P>
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| 26 | <OL>
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| 27 | <LI>Both approaches are <I>not suited for outdoor scenes</I> (except scenes which are technically indoor-scenes).</LI>
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| 28 | <LI>It is <I>hard to automatically place portals efficiently</I>, so it normally has to be done by hand.</LI>
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| 29 | <LI><I>Portals</I> are by nature a very <I>conservative visibility approximation</I>.</LI>
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| 30 | <LI><I>Portals</I> are <I>not suited for dynamic occluders</I>.</LI>
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| 31 | <LI>For maximum efficiency <I>Quake style PVS </I>is usually done on a scene<I> stored in a BSP tree</I>, which, amongst other drawbacks, is a scene data structure <I>not well suited for dynamically changing scenes</I>.</LI>
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| 32 | <LI><I>Quake style PVS</I> precalculation can take prohibitively long.</LI>
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| 33 | </OL>
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| 34 | <P STYLE="margin-top: 6pt;">The <B>GTP VisibilityLib</B> will overcome these problems with a 2-phase strategy: </P>
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| 35 | <OL>
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| 36 | <LI>A solution which supplies <B>precalculated visibility</B> based on <B>modern visibility research</B>, also suited for <B>outdoor scenes</B>.</LI>
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| 37 | <LI>A solution which efficiently employs <B>modern day graphic hardware</B> to deliver <B>on-the-fly visibility</B> with <B>minimal overhead</B>.</LI>
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| 38 | </OL>
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| 39 | <P> Both solutions work best when used together, but can also be employed independently from one another, as to best suit the 3D/game engine in use.</P>
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| 40 | <P> </P>
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| 48 | <P><IMG ID="Bild2" HEIGHT=200 WIDTH=266 SRC="../assets/images/autogen/a_city_highestres_noseam.gif" VSPACE=0 HSPACE=0 ALIGN="TOP" BORDER=1 STYLE="border-left-color: rgb(0,102,204); border-left-style: solid; border-top-color: rgb(0,102,204); border-top-style: solid; border-right-color: rgb(0,102,204); border-right-style: solid; border-bottom-color: rgb(0,102,204); border-bottom-style: solid;" ALT="city_highestres_noseam" TITLE="city_highestres_noseam"></P>
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| 49 | </TD>
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| 50 | <TD>
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| 51 | <P><IMG ID="Bild3" HEIGHT=200 WIDTH=266 SRC="../assets/images/autogen/a_overview_highestres.gif" VSPACE=0 HSPACE=0 ALIGN="TOP" BORDER=1 STYLE="border-left-color: rgb(0,102,204); border-left-style: solid; border-top-color: rgb(0,102,204); border-top-style: solid; border-right-color: rgb(0,102,204); border-right-style: solid; border-bottom-color: rgb(0,102,204); border-bottom-style: solid;" ALT="overview_highestres" TITLE="overview_highestres"></P>
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| 52 | </TD>
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| 53 | <TD>
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| 54 | <P><IMG ID="Bild4" HEIGHT=200 WIDTH=276 SRC="../assets/images/autogen/a_city_vis_highestres_aa.gif" VSPACE=0 HSPACE=0 ALIGN="TOP" BORDER=1 STYLE="border-left-color: rgb(0,102,204); border-left-style: solid; border-top-color: rgb(0,102,204); border-top-style: solid; border-right-color: rgb(0,102,204); border-right-style: solid; border-bottom-color: rgb(0,102,204); border-bottom-style: solid;" ALT="city_vis_highestres_aa" TITLE="city_vis_highestres_aa"></P>
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| 55 | </TD>
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| 61 | </P>
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| 62 | <P> </P>
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| 63 | </TD>
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| 76 | </TABLE>
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| 77 | </BODY>
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| 78 | </HTML>
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| 79 | |
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