或言靖边名将，武林巨擘皆武曲星谪下凡尘。是可信欤？缘李小龙故，吾宁信
之。

本实例试图体现的就是李小龙回归到那苍苍中武曲星座里的景象：

（一〕从第一行开始：

#VRML V2.0 utf8 

WorldInfo {   
   title "永恒"   
   info [   
      "Author: 金臂螳螂",   
      "Date: March 1, 1998 (Sun)"  
   ]   
}   

NavigationInfo {   
   type "EXAMINE"   
}

Background {   
      groundAngle [0.523, 1.047, 1.571]  
      groundColor [0 0 0, 0 0 1, 0 0 1, 0 1 1]  
      skyAngle [0.523, 1.047, 1.571]  
      skyColor [1 1 1, 1 1 1, 0 1 1, 0 1 1]  
}

Group {  
   children [   

      DEF EntryView Viewpoint { #此虚拟实境亦规定了进入，内外三个视点。 
      fieldOfView 1.57   
      orientation 1 0 0 0.79   
      position 0.0 -7.0 10.0   
      description "EntryView"  
      },

      DEF Outside Viewpoint {   
      position 0 0 40   
      description "Outside"   
      },

      DEF Inside Viewpoint {   
      position 0 0 6  
      description "Inside"   
      }   

   ]   
}

（二〕设计星座：

Group {  
   children [   

   DEF Lee Transform {   
     children Shape {   
       appearance Appearance {   
       material Material { emissiveColor 1.0 0.5 0.0 }   
       texture ImageTexture {url "stand.gif"}  #粘贴图案为李小龙。 
       }   
       geometry Box {size 3 3 3}   #立方体   
     },   
   },

   DEF Lee Transform {   
      

      children Shape {   
         appearance Appearance {   
         material Material {   
            emissiveColor 1.0 0.5 0.0    
            transparency 0.8   #颜色及透明的协调形成一雾状球网。 
         }   
         }   
         geometry Sphere {radius 10}    #圆球   
       },   
   },

   DEF Long Transform {   
      translation 4.0 0.0 0.0    
      center -4.0 0.0 0.0    
         children [    
            Shape {    
            appearance Appearance {    
            material Material {    
            diffuseColor 0.0 0.0 1.0    
            specularColor 0.9 0.9 0.9   
            shininess 0.3    
            }   
            texture ImageTexture {url "reptile.gif"}  #粘贴图案为龙。 
            }    
            geometry Sphere { radius 0.5 }    #球A，绕立方体(李小龙)旋转。 
   },

   DEF Snake Transform {    
      translation 1.0 0.0 0.0    
      center -1.0 0.0 0.0    
         children Shape {    
            appearance Appearance {    
            material Material {    
            diffuseColor 0.7 0.7 0.7    
            shininess 1.3    
            }    
            }    
            geometry Sphere {radius 0.2}   #球B，绕球A旋转。  
          }    
       }    
   ]   
},

以上，以李小龙(立方体)为恒星，另设球A绕李小龙转，球B绕球A转。最外层有一
个雾状球型网，罩住星座以增加些神秘感。

（三〕设计星座的旋转：

DEF Bruce TimeSensor {   
   cycleInterval 8.0   
   loop TRUE   
},

DEF Reptile TimeSensor {   
   cycleInterval 5.0   
   loop TRUE   
},

DEF Serpent TimeSensor {   
   cycleInterval 2.0   
   loop TRUE   
},

DEF LeePath OrientationInterpolator {    
   key [ 0.0, 0.50, 1.0 ]    
   keyValue   
      [ 0.0 0.0 1.0  0.0,   
      0.0 0.0 1.0  3.14,   
      0.0 0.0 1.0  6.28 ]   
},

DEF LongPath OrientationInterpolator {   
   key [ 0.0, 0.50, 1.0 ]   
   keyValue    
      [ 0.0 0.0 1.0  0.0,   
      0.0 0.0 1.0  3.14,   
      0.0 0.0 1.0  6.28 ]   
},

DEF SnakePath OrientationInterpolator {    
   key [ 0.0, 0.50, 1.0 ]   
   keyValue    
      [ 0.0 0.0 1.0  0.0,   
      0.0 0.0 1.0  3.14,   
      0.0 0.0 1.0  6.28 ]   
      }   
   ]    
}

ROUTE Bruce.fraction_changed  TO LeePath.set_fraction   
ROUTE Reptile.fraction_changed TO LongPath.set_fraction   
ROUTE Serpent.fraction_changed TO SnakePath.set_fraction   
ROUTE LeePath.value_changed  TO Lee.set_rotation   
ROUTE LongPath.value_changed  TO Long.set_rotation   
ROUTE SnakePath.value_changed  TO Snake.set_rotation

#以上事件的设计教为复杂，不再赘述。提纲掣领，慢慢推求，自然明澈。
#不过一点数理，又有何难？

#学而不知数理，犹如宝镜微尘，世上六艺乱纷纷，数乃人之根本。
#聪明蒙童易得，愚昧皓首难成，漫同高士共评论，数澈不差分寸。


（四〕至此，将所有红色指令按其出现的顺序剪切到一个文件里作为源码，再存
为*.wrl文件，如e_Dragon.wrl。

最后，浏览此e_Dragon.wrl虚拟实境，并逐一对照核实源码中所言效果，以知
其所以然。

练习题：阅读并理解此虚拟实境之源码，修改源码，取消雾状网。