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celestia源代码

In general, to run the basic &celestia; solar system program, your computer should have a CPU (processor) that has a speed of at least 300 million cycles per second (300 MHz).  Typically, computers bought new within the last 2 -3 years have adequate CPU speeds.  If your computer is more than 3 years old or is a Pentium II or equivalent with a processor speed slower than 300 MHz, &celestia; may run slowly and you will be disappointed.
</para><para>
The basic &celestia; program also requires a minimum of 128 megabytes of RAM memory.  The graphics files that &celestia; use are large, and if your computer does not have at least 128 megabytes of RAM, &celestia; may run very slowly, not run at all or may lock up.  In addition, if you wish to explore &celestia;'s maximum capabilities, you will need 256 megabytes of RAM memory, with 512 megabytes of RAM recommended.
</para><para>
Although it's not absolutely required, the program will be vastly more enjoyable if you also have a 3D video graphics accelerator in your computer.  This is hardware circuitry that draws complex graphic images on your video display monitor.  &celestia; should run with any 3D accelerator card with at least 8 megabytes of memory.  However, a 16 megabyte or 32 megabyte card is preferred if you intend to use &celestia;'s most detailed graphic files.  If you have such a card, &celestia; will run smoothly and its graphics will be complete, crisp and sharp.  If is runs too slowly, is blurry, locks up, or objects appear to be moving with jerky motions, you may need to locate a faster computer or one with more memory or graphics capability.
</para>
<important>
<para>&celestia; uses the OpenGL API to render 3D graphics.  In order to get the most from Celestia, you should have a modern OpenGL graphics card with the latest drivers from the manufacturer.  If you have problems running &celestia;, verify that your graphics card is capable enough to run &celestia;, and that the drivers are up to date.  If in doubt about the OpenGL driver, download and install a new one.  It will be available free from your card maker's web site.  Having a new driver is the best thing you can do to ensure that &celestia; runs properly.
</para>
<para>
While a graphic video card might use Open GL processing, &celestia; does not run well on all such ca
rd brands or models.  Version 1.3.0 incorporates major improvements to render &celestia; more compatible with as many brands of cards as possible, but several graphic cards handle images in a manner that &celestia; may not control properly.  To date, &celestia;'s features work best on the video chipsets manufactured by NVIDIA, Inc.  Those video cards sell under the model names "Riva", "GeForce" and "Quadro".  If an NVIDIA Open GL card is not present in your computer, &celestia; can still offer you a beautiful solar system experience, but some of its advanced features may not function.  These include shadows on mountains and craters (bump mapping), sunlight reflections off water (specular highlights), shadows of moon eclipses, and atmospheric haze.
</para><para>
As development of &celestia; continues, better support for graphics hardware will continue to be introduced; if not all the features of your graphics card are supported yet, be patient.  Better yet, join the &celestia; development team and help improve the program.
</para></important>
</chapter>

<chapter id="installation_uninstallation">
<title>Installation and Uninstallation</title>
<para>
If you have a video card incorporating a graphics accelerator with at least 32 MB of memory, install the full &celestia; installation (i.e. - celestia-win32-1.3.1.exe).  If your computer is an older model, does not have a graphics accelerator or does not support Open GL processing, obtain the &celestia; package with low-resolution textures and install that.  The views you see in &celestia; will be simpler and less detailed, but this version of the program and its files require less RAM and it may run more smoothly.  Also, see the &celestia; website for additional <ulink url="http://www.shatters.net/celestia/faq.html">answers to troubleshooting questions</ulink>.  Alternatively, the main &celestia; package includes some low-resolution image files.  While running &celestia;, you can actually switch from one resolution of graphics to another by tapping the &hiresolution; key on the keyboard (for large resolution), or the &loresolution; key (to change to low resolution images).  This alone may speed up your program.  Note, however, that not every image in &celestia; is represented by both a high and low-resolution image.  If you tap the &loresolution; key and nothing happens, it just means there is no smaller resolution image of that moon or asteroid or spacecraft to use.
</para>

<sect1 id="win">
<title>Windows Operating System (95, 98, ME, 2000, NT, XP)</title>
<para>
Once you have obtained and downloaded the executable file, simply click twice (double-click) rapidly on its name with your left mouse button.  The file will begin running and will install &celestia;.  In general, just click <guibutton>Next</guibutton> whenever it asks a question.  &celestia; has its preferred choices and unless you have reasons for altering them, we suggest you follow them.
</para>
</sect1>

<sect1 id="mac">
<title>Macintosh OS Operating Systems</title>
<para>
To install the Macintosh version, click on it and follow the on-screen menu instructions.
</para>
</sect1>

<sect1 id="linux">
<title>Linux Operating Systems</title>
<para>
RPMS packages are provided for the SuSE and Mandrake distribution. You can get them from the SourceForge <ulink url="http://sourceforge.net/project/showfiles.php?group_id=21302">project page</ulink>.
</para>
<para>
If you run SuSE or Mandrake the prefered way to install &celestia; is to get the <filename>celestia-kde</filename>, <filename>celestia-kde-texture</filename> and <filename>celestia-kde-handbook</filename> packages for your distribution and to install them by running as root in the directory where the files have been downloaded:</para>
<para><userinput><command>rpm</command> <option>-Uvh</option> <filename>celestia-kde*</filename></userinput>
</para>
<para>
Alternatively, or if you don't run one of the supported distribution, you can compile &celestia; yourself.
Unpack it and its libraries with gzip and tar via the command:</para>
<para><userinput><command>gzip</command> <option>-dc</option> <filename>celestia-1.3.1.tar.gz</filename> <command>| tar</command> <option>xvf</option></userinput></para>
<para>
Then change directory (<command>cd</command>) into the newly created directory and configure Celestia.  Run <command>configure</command> with the appropriate command line for the version that you want to compile:</para>
<variablelist>
<varlistentry>
<term>KDE</term>
<listitem><para><userinput><command>./configure</command> <option>-with-kde</option></userinput></para></listitem>
</varlistentry>
<varlistentry>
<term>Gnome/Gtk</term>
<listitem><para><userinput><command>./configure</command> <option>-with-gtk</option></userinput></para></listitem>
</varlistentry>
<varlistentry>
<term>GLUT</term>
<listitem><para><userinput><command>./configure</command></userinput></para></listitem>
</varlistentry>
</variablelist>
<note><para>To enable the CELX script language (new in 1.3.1), add <option>--with-lua</option> to the <command>configure</command> command. You need to have <ulink url="http://www.lua.org/">Lua 5</ulink> installed. Lua 5 packages are available for Mandrake in the "contrib" directory on Mandrake mirrors.</para></note>
<para>
<command>configure</command> may complain if you are missing a required component, or if you have an out of date version of a required component.  Check the error output from configure to determine what's missing, install the necessary items, and then try rerunning <command>configure</command>.  If neither the KDE or Gnome versions of &celestia; will build, try falling back to the GLUT version.  There are many options for configure; you can view them all-together with a brief explanation for each-by running <userinput><command>./configure</command> <option>-help</option></userinput>.
</para>
<para>After running configure, compile and install &celestia;:</para>
<para><userinput><command>make</command></userinput></para>
<para><userinput><command>make</command> <option>-install</option></userinput></para>
<note><para><command>make</command> <option>-install</option> will need to be run as root unless you've overridden the default install directory by invoking <command>configure</command> with the <option>-prefix</option> option.
</para></note>
<para>
Hopefully, compilation of &celestia; will go smoothly.  If it doesn't, it's most likely because some required package is missing.  A relatively common problem is that the OpenGL developer package necessary for building OpenGL applications has not been installed.  If the compiler complains that gl.h or glu.h is not found, it's a symptom of a missing or improperly installed OpenGL developer package.  Once make completes without errors, you're ready to run &celestia; from either your desktop of choice or the command line.
</para>
</sect1>

<sect1 id="uninstall">
<title>Uninstall</title>
<para>
To uninstall &celestia; in Windows, click the <guibutton>Start</guibutton> button at the bottom left of your screen, select <guisubmenu>Settings</guisubmenu>, then select <guimenuitem>Control Panel</guimenuitem>, then select Add/Remove Programs.  Locate &celestia; in the pull-down list and click the button that says, "Add/Remove". </para>
<para> For Apple and UNIX owners, follow your system's standard uninstall procedure.
</para>
</sect1>

</chapter>


<chapter id="general_operation">
<title>General Operation and Keyboard commands</title>
<note><para>In the sections that follow, images and screenshots from the program will be displayed.  Many of these images use higher-resolution graphic add-ons that are not part of the default download program, but which are available from the &celestia; forum and other websites.  As a result, if your version of &celestia; does not precisely match the enclosed screenshots, don't be alarmed.</para></note>
<para>
To launch &celestia;, double-click on its icon either on your desktop or in the Programs menu that appears when you click your Start button.  The program will load and will open far out in space hovering above Io, one of Jupiter's most fascinating moons.  Mighty Jupiter will be visible somewhere behind Io.  The beauty of &celestia; is its accuracy.  The image in front of you is exactly what you would see if you were really positioned in space at that very spot right now.  In other words, Io, Jupiter, and all of the planets and stars and spacecraft visible on your computer screen really are located in space where &celestia; has put them.</para>

<para>The Opening Screen:</para>

<screenshot>
<screeninfo>Earth</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="fig1.jpg" format="PNG" />
</imageobject>
<textobject>
<phrase>Earth</phrase>
</textobject>
<caption><para><ulink url="cel://Follow/Sol:Earth/2003-08-30T16:07:23.18386?x=0HIjR+0qNFbMDA&amp;y=x8yXF3Dy&amp;z=oTFzSBjgc0YG&amp;ow=0.554402&amp;ox=-0.000000&amp;oy=0.832249&amp;oz=-0.000000&amp;select=Sol:Earth&amp;fov=31.999998&amp;ts=1.000000&amp;ltd=0&amp;rf=40855&amp;lm=1862270976">Earth</ulink></para></caption>
</mediaobject>
</screenshot>

<para>Earth turns on its axis constantly and is always changing position.  Thus, the screenshot above may or may not be the same scene you see when you open &celestia;.  However, it will be similar</para>

<itemizedlist>
<listitem><para>In the top left corner will be some information about your target (Io).  The Distance will be the distance in kilometers (km) from you to the surface of the moon.  Io's Radius in km will also be listed.</para></listitem>
<listitem><para>In the lower left corner will be Speed through space relative to the Sun.  At the moment, your ship is not moving so your speed is zero.  Later, we will begin to fly on our own and your speed will be listed here.</para></listitem>
<listitem><para>In the top right corner will be the current time and date.  In Astronomy, times are given in Universal Time (commonly referred to as Greenwich Mean Time), and this is what &celestia; uses by default.  If you find it more convenient, you can access the Time menu to make &celestia; use your local time zone instead.  The date is listed in the format (year/month/day).  Note that time will be in 24-hour format.  Thus, 1:00 PM will be 13:00:00 hours.  &celestia; can also speed up or slow down time or travel forward or backward in time with the touch of a button.  Now, you are experiencing the program in "Real Time".</para></listitem>
<listitem><para>In the lower right of the screen will be a message telling you that you are "Following" Earth.  Wherever it goes, you go.  Thus, although Earth is actually moving rapidly through space, you are moving with it.</para></listitem>
<listitem><para>Under that will be your <quote>Field of View</quote> or <quote>FOV</quote>. This is the amount of sky your view takes in.  &celestia; starts you out with an FOV that it calculates, based upon your screen size, resolution and monitor settings.  It ranges from 15掳 to 45掳, which means your monitor is displaying about 15掳 - 45掳 of the sky (most people have a total visual field of 120掳).  However, you can change the FOV easily by holding down the &Shift; key on the keyboard, <mousebutton>left</mousebutton>-clicking your mouse button and dragging the mouse forward or backward.  Try it.  As the FOV gets smaller, the scene enlarges.  It is similar to a telescope magnification.  You can also press the &dec_fov; key or the &inc_fov; keys to change field of view from the keyboard.  Enlarging the FOV allows you to magnify objects in the distance, while still keeping the planet in the foreground.  In general, an FOV of about 32掳 presents a sky view that draws objects at about the size you see them in space.  If you wish to return to the default FOV that your program opened with and you have a mouse wheel, click/push the <mousebutton>wheel</mousebutton> button.  Please note that if you change your screen window size by dragging its borders, &celestia; may assign and change the FOV, based on the new screen size.</para></listitem>
<listitem><para>
You can also instruct &celestia; to launch the program with a particular starting FOV, rather than sizing it based on your screen settings.  To do so, locate the file named <filename>start.cel</filename>, which is in the &celestia; main Directory folder.  <mousebutton>right</mousebutton>-click on it and choose the option that says, <guimenuitem>open with</guimenuitem>.  A list of programs on your computer will appear.  Locate a text editing program such as MS WordPad or Notepad and click <guibutton>OK</guibutton>.  The <filename>start.cel</filename> file will open and you鈥檒l see a set of single line commands (in English).  Locate the line that says,
<programlisting>
# set { name "FOV" value ____ }
</programlisting>
Remove the # symbol and in the space, type whatever FOV value you wish.  For example:
<programlisting>
set { name "FOV" value 32.0 }
</programlisting>
produces a 32掳 field of view that is about what your eyes would see without a telescope if looking at the Moon or a particular spot in space.
Save the file, close it and launch &celestia;.  The program will now always start with an FOV of 32掳.
</para>
</listitem>

</itemizedlist>

<informaltable pgwide="1">
<tgroup cols="2">
<tbody>
<row>
<entry>
<screenshot>
<screeninfo>The FOV here is 45掳.  Notice size of the moon behind Earth.</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="fig2.jpg" format="PNG" />
</imageobject>
<textobject>
<phrase>The FOV here is 45掳.  Notice size of the moon behind Earth.</phrase>
</textobject>
<caption><para><ulink url="cel://Follow/Sol:Earth/2003-03-22T18:59:45.88?x=OD6Jd5I3xO6tDA&amp;y=TuD9jqpi/f///////////w&amp;z=hVjrjdVgKXc&amp;ow=-0.363648&amp;ox=0.079560&amp;oy=0.927376&amp;oz=0.037466&amp;select=Sol:Earth&amp;fov=45.000004&amp;ts=1.000000&amp;rf=57239&amp;lm=0">The FOV here is 45掳.  Notice size of the moon behind Earth.</ulink></para></caption>
</mediaobject>
</screenshot>
</entry><entry>
<screenshot>
<screeninfo>The FOV here is 12掳.  Earth and moon are now enlarged.</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="fig3.jpg" format="PNG" />
</imageobject>
<textobject>
<phrase>The FOV here is 12掳.  Earth and moon are now enlarged.</phrase>
</textobject>
<caption><para><ulink url="cel://Follow/Sol:Earth/2003-03-22T19:01:27.24?x=4P8Iu2jRse6tDA&amp;y=rV64OPKX/////////////w&amp;z=FdjZPUzzKHc&amp;ow=-0.255431&amp;ox=0.084504&amp;oy=0.962843&amp;oz=0.023405&amp;select=Sol:Earth&amp;fov=12.053194&amp;ts=1.000000&amp;rf=57239&amp;lm=0">The FOV here is 12掳.  Earth and moon are now enlarged.</ulink></para></caption>
</mediaobject>
</screenshot>
</entry>
</row>
</tbody>
</tgroup>
</informaltable>