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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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7 | <META NAME="Generator" CONTENT="NetObjects Fusion 8 für Windows">
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14 | <BODY NOF="(MB=(DefaultMasterBorder, 121, 127, 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=26 HEIGHT=54><IMG SRC="../assets/images/autogen/clearpixel.gif" WIDTH=26 HEIGHT=1 BORDER=0 ALT=""></TD>
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18 | <TD WIDTH=834><IMG SRC="../assets/images/autogen/clearpixel.gif" WIDTH=834 HEIGHT=1 BORDER=0 ALT=""></TD>
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19 | </TR>
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21 | <TD></TD>
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22 | <TD WIDTH=834 CLASS="TextObject" STYLE="background-color: rgb(255,255,255);">
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23 | <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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24 | <OL>
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25 | <LI>Both approaches are <I>not suited for outdoor scenes</I> (except scenes which are technically indoor-scenes).</LI>
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26 | <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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27 | <LI><I>Portals</I> are by nature a very <I>conservative visibility approximation</I>.</LI>
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28 | <LI><I>Portals</I> are <I>not suited for dynamic occluders</I>.</LI>
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29 | <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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30 | <LI><I>Quake style PVS</I> precalculation can take prohibitively long.</LI>
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31 | </OL>
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32 | <P STYLE="margin-top: 6pt;">The <B>GTP VisibilityLib</B> will overcome these problems with a 2-phase strategy: </P>
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33 | <OL>
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34 | <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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35 | <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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36 | </OL>
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37 | <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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38 | <P> </P>
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39 | <P>
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40 | <TABLE WIDTH=834 BORDER=0 CELLSPACING=0 CELLPADDING=0 ALIGN=LEFT NOF=TE>
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43 | <TABLE ID="Tabelle1" BORDER=0 CELLSPACING=2 CELLPADDING=2 WIDTH="100%">
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44 | <TR>
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46 | <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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47 | </TD>
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48 | <TD>
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49 | <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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50 | </TD>
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51 | <TD>
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52 | <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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53 | </TD>
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60 | <P> </P>
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