particle systems and removes all systems which died after the 
                  update.</TD></TR>
              <TR bgColor=#ffffff>
                <TD class=ColorCode vAlign=top width="18%">Render</TD>
                <TD class=EtoC colSpan=2 vAlign=top>Renders all active and 
                  visible systems.</TD></TR>
              <TR bgColor=#ffffff>
                <TD class=ColorCode vAlign=top width="18%">Shutdown</TD>
                <TD class=EtoC colSpan=2 vAlign=top>Shuts down the manager 
                  (removes all allocated systems).</TD></TR>
              <TR bgColor=#ffffff>
                <TD class=ColorCode vAlign=top width="18%">DoesExist</TD>
                <TD class=EtoC colSpan=2 vAlign=top>Checks whether a given 
                  particle system still exists in the particle manager (if it 
                  has not been removed yet).</TD></TR>
              <TR bgColor=#ffffff>
                <TD class=BGRed colSpan=3 vAlign=top>
                  <DIV align=center><B><FONT color=#cccccc>表3 
                  粒子管理器類的成員函數</FONT></B></DIV></TD></TR></TBODY></TABLE><BR>　　AddSystem函數可能只有一個參數：指向粒子類的指針。這將允許你根據需要輕易地增加一個煙系統或火系統。下面是我如何在引擎中增加一個粒子系統的例子：<BR><BR>　　<SPAN 
            class=ColorCode>gParticleMgr-&gt;AddSystem( new 
            Smoke(nrSmokeParticles, position, ...) 
            );</SPAN><BR><BR>　　在世界更新函數中我調用了gParticleMgr-&gt;Update()函數，這個函數自動更新所有的系統并釋放死亡的系統。Render函數然后渲染所有的可見粒子系統。因為我們不想在每一幀跟蹤系統中的所有粒子以判斷是否所有的粒子均已死亡（這樣系統可被刪除），我們將使用Update函數來代替。如果這個函數返回TRUE，這意味著系統處于存活狀態。反之系統已死亡并可以被刪除。粒子管理程序的Update函數如清單2所示。<BR><BR>　　<SPAN 
            class=ColorCatchword>// 清單2 - Update function of the particle 
            manager.</SPAN><BR>　　<SPAN class=ColorCode>for (int i=0; 
            i&lt;particleSystems.Length())</SPAN>　　<SPAN class=ColorCatchword>// 
            traverse all particle systems<BR></SPAN>　　<SPAN 
            class=ColorCode>{<BR>　　　　if 
            (!particleSystems[i]-&gt;Update())</SPAN>　　　 <SPAN 
            class=ColorCatchword>// if the system died, remove 
            it<BR></SPAN>　　　　<SPAN class=ColorCode>{<BR>　　　　　　delete 
            particleSystems[i];</SPAN>　　　　　 <SPAN class=ColorCatchword>// 
            release it from memory<BR></SPAN>　　　　　　<SPAN 
            class=ColorCode>particleSystems.SwapRemove(i);</SPAN>　　　 <SPAN 
            class=ColorCatchword>// remove number i, and fill the 
            gap<BR>　　　　　　　　　　　　　　　　　　　　　　　　 // with the last entry in the 
            array<BR></SPAN>　　　　<SPAN 
            class=ColorCode>}<BR>　　　　else<BR>　　　　　　i++;<BR>　　}</SPAN><BR><BR>　　在我的粒子系統中，其中分配的所有具有相同底紋和混合方式的粒子將連續地渲染，同時將底紋轉換和上載減到最小。這樣，如果在屏幕上有十個可見的煙系統，就只有一個底紋轉換和狀態改變將被執行。<BR><A 
            name=5.0></A><BR><B>5、設計，然后再編碼</B><BR>　　設計一個靈活的，快速的和可擴展的高級粒子系統并不很困難，如果你花時間來考慮你將如何在游戲中使用它，并且由此細致設計你的系統。由于在此討論的系統使用帶有繼承的類，你也可以在.DLL文件中加入獨立的粒子系統形式。這就使建立某種插件（<SPAN 
            class=English>Plug-In</SPAN>）系統成為可能,而這可能是某些開發者所感興趣的。<BR>　　你也可以下載我的粒子系統（我為Oxygen3D開發的最新的引擎）的源程序。這些源碼不是獨立的可編輯系統，但如果你遇到問題，它應該能幫助你。如果你還有任何問題或意見，請直接給我發電子郵件。<BR><BR>　　<IMG 
            height=16 src="download.gif" width=16> <A 
            class=BlackLink 
            href="http://mays.soage.com/develop/effect/200111/image/AParSystem/AdvancedParticles.zip">附帶的源程序</A>（12K）、<A 
            class=BlackLink 
            href="http://www.mysticgd.com/misc/AdvancedParticleSystems.pdf">英文版的原稿</A>（PDF 
            1.0MB）<BR><BR>
            <HR align=center noShade SIZE=1 width="95%">
            <BR>　　<B>原作者及其它</B><BR>　　<SPAN class=English>John van der Burg is 
            the lead programmer for Mystic Game Development, located in the 
            Netherlands. Currently he is working on Oxygen3D, which is his third 
            hardware-only engine and his eighth engine overall. Currently he is 
            doing freelance work on LOOSE CANNON for Digital Anvil and for OMG 
            Games on THE CREST OF DHARIM. He previously freelanced for Lionhead 
            Studios on BLACK AND WHITE, and for Orange Games on CORE. You can 
            find screenshots of his previous work at <A class=cLink 
            href="http://www.mysticgd.com/" 
            target=_blank>http://www.mysticgd.com/</A>.Feel free to drop him a 
            line at<A class=cLink 
            href="mailto:john@mysticgd.com.">mailto:john@mysticgd.com.</A>.</SPAN><BR><BR>
            <TABLE align=center border=0 cellPadding=2 cellSpacing=0 
class=BGRed>
              <TBODY>
              <TR>
                <TD align=middle><IMG height=250 
                  src="APSother-4.jpg" width=250></TD>
                <TD><FONT color=#cccccc face="Times New Roman, Times, serif">A 
                  blood system. Blood colors were set based on the colors in the 
                  light maps. Blood on dark areas looks dark as well. The red 
                  areas in the bottom screenshot are the blood splats on the 
                  camera lens, dripping down the lens. 
            </FONT></TD></TR></TBODY></TABLE><BR>
            <TABLE align=center border=0 cellPadding=2 cellSpacing=0 
class=BGRed>
              <TBODY>
              <TR>
                <TD align=middle><IMG height=250 
                  src="APSother-5.jpg" width=250></TD>
                <TD><FONT color=#cccccc 
                  face="Times New Roman, Times, serif">This was constructed from 
                  sparks and a big real-time calculated flare explosion (not 
                  just a texture). </FONT></TD></TR></TBODY></TABLE><BR>
            <TABLE align=center border=0 cellPadding=2 cellSpacing=0 
class=BGRed>
              <TBODY>
              <TR>
                <TD align=middle><IMG height=250 
                  src="APSother-6.jpg" width=250></TD>
                <TD><FONT color=#cccccc 
                  face="Times New Roman, Times, serif">This image is the same as 
                  the above one, but with some extra animated explo- sions 
                  (animated textures) and shockwaves, which are admittedly very 
                  small and may be difficult to see in this 
              image.</FONT></TD></TR></TBODY></TABLE><BR>
            <TABLE align=center border=0 cellPadding=2 cellSpacing=0 
class=BGRed>
              <TBODY>
              <TR>
                <TD align=middle><IMG height=250 
                  src="APSother-7.jpg" width=250></TD>
                <TD><FONT color=#cccccc 
                  face="Times New Roman, Times, serif">This electricity has its 
                  own render function. A hierarchy tree was constructed to 
                  represent the electricity flow using branches and 
                  sub-branches. It is a thunder- storm lightning effect with the 
                  branches animated. Particle shapes are being con- structed for 
                  every part in the electricity 
            tree.</FONT></TD></TR></TBODY></TABLE><BR>
            <TABLE align=center border=0 cellPadding=2 cellSpacing=0 
class=BGRed>
              <TBODY>
              <TR>
                <TD align=middle><IMG height=250 
                  src="APSother-8.jpg" width=250></TD>
                <TD><FONT color=#cccccc face="Times New Roman, Times, serif">A 
                  rain effect, using stretched shapes for the particles. The 
                  rain also splats on the ground by calling the sparks system 
                  with adjusted settings and texture.</FONT></TD></TR></TBODY></TABLE><!-- #EndEditable --></TD></TR>
        <TR>
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