// Persistence of Vision Ray Tracer Scene Description File

// File: ?.pov

// Vers: 3.5

// Desc: 2nd part of b_field

// Date: 11/30/04

// Auth: cdk

//



#version 3.5;



#include "colors.inc"



global_settings {

  assumed_gamma 1.0

  ambient_light color rgb <1,1,1>

}

background { color rgb <.1, .4, .7> }  


//some handy recyclable definitions

#declare lclock=clock+.20001;
                                  
#macro make_arrow(draw_vector,arrow_cap_length,arrow_cap_width,arrow_width)

  #local vector_length=vlength(draw_vector);  
  union{                             
     #if(vector_length<= arrow_cap_length)   
          //cone { <0, 1, 0>, 0.0, <0, -1, 0>, 1.0 }
          cone{0*x,vector_length/arrow_cap_length*arrow_cap_width,draw_vector,0} 
          #else                   
cone{draw_vector*(vector_length-arrow_cap_length)/vector_length,arrow_cap_width,draw_vector,0}           
cylinder{0*x,draw_vector*(vector_length-arrow_cap_length)/vector_length,arrow_width}    
     #end

  }

#end

/*

cylinder{0,.5*x,.032  texture{mrg_red_texture} translate cp}

object{ 

        make_arrow(draw_vector,arrow_cap_length,arrow_cap_width,arrow_width)    
   

        make_arrow(1.0*x,headl,headw,awidth)

        texture{mrg_red_texture} translate cp

         }



*/

#declare mrg_green_texture=

        texture {
          pigment {          // (---surface color---) 
                color rgb <.0,.7,.0>
                   }

          finish {         // (---surface finish---)      
            ambient 1.0   
            specular 0.1     // shiny
            }

        }                 

        #declare mrg_blue_texture=   
        texture {
          pigment {          // (---surface color---)    
                color rgb <.0,0,3>      
          }

          finish {           // (---surface finish---) 
            ambient 1.0    
            specular 0.04     // shiny
          }
        }          

        #declare black_texture=   
        texture {    
          pigment {          // (---surface color---)  
                color rgb <1,1,1>  
          }    
          finish {           // (---surface finish---)  
            ambient 1.0 
            specular 0.1     // shiny     
          }             
        } 
          #declare pink_texture=   
        texture {    
          pigment {          // (---surface color---)  
                color rgb <1,0,1>  
          }    
          finish {           // (---surface finish---)  
            ambient 1.0 
            specular 0.1     // shiny     
          }             
        } 

        #declare mrg_red_texture= 
        texture {     
          pigment {          // (---surface color---)
                  color rgb <.80,0,.0>
                  }
          finish {           // (---surface finish---)
                ambient 1.0
                specular 0.1     // shiny
                 }
              }

#declare ds=.01;        //declare length of segment 
#declare sfinal = lclock; 
#declare R=5; 
#declare xpos = function(ss) { sin(2*pi*ss) }    //declare x position   
#declare ypos = function(ss) { cos(2*pi*ss) }     //declare y position
#declare zpos = function(ss) { 0 }                //declare z position 
#declare b = 0;     
//vector drawing sizes

#declare arrow_cap_length =.2;

#declare arrow_cap_width =arrow_cap_length*.5;

#declare arrow_width =arrow_cap_width/4;



             
#declare field_point=<0, 0, -3>;           //declare field point

#declare s =0;
#while (s<sfinal) 

#declare source_point=<xpos(s), ypos(s), zpos(s)>;  //declare source  point  
#declare vec_r = field_point - source_point;
 
#declare dl = <xpos(s+ds), ypos(s+ds), zpos(s+ds)> - <xpos(s), ypos(s),
zpos(s)>;

#declare vdl= dl/vlength(dl);   

//adding dB       
#declare dB= -vcross(dl, vec_r)/pow(vlength(vec_r), 3)*200;

         /*cylinder { 0, dB, .025 

                translate field_point

                texture {mrg_blue_texture}

                no_shadow}   */
        
         
  #declare b = b+ dB;
  #declare s = s + ds;
  #end                 
                   
 object{ 

       make_arrow(b/15,arrow_cap_length,arrow_cap_width,arrow_width)        

        texture{mrg_blue_texture} translate field_point

         no_shadow} 


/*cylinder { 0, vec_r, .02        
            translate source_point             //draws r hat       
            texture{pink_texture}         
            no_shadow} 
            */
            
            object{ 

       make_arrow(vec_r,arrow_cap_length,arrow_cap_width,arrow_width)        

        texture{pink_texture} translate source_point

         no_shadow}        
            
            
                                   
cylinder { <-5, 0, 0>, <5, 0, 0>, .02        
                texture{black_texture}              //x, y, z axis  
                no_shadow}
                                                           

cylinder { <0, -5, 0>, <0, 5, 0>, .02  
                texture{black_texture}  
                no_shadow}                            

cylinder { <0, 0, 5>, <0, 0, -5>, .02
                texture{black_texture}   
                no_shadow}           









camera {
  location  <5.5,2, -7.0>
  right     x*image_width/image_height
  look_at   <0, 0, 0>
  angle 60
}




/* */

light_source {

  <2, -3, 2>            // light's position (translated below)

  color rgb <6, 1, 1>  // light's color

  translate <-10, 8, -20>//place it to the left (neg x), above (pos y) and
//behind (neg z) vantage point

}



// ----------------------------------------



 
  //draw entire current segment

#declare s=0;  


  #declare field_point=<0, 0, -3>;           //declare field point

#declare source_point=<xpos(s), ypos(s), zpos(s)>;  //declare source  point


#while (s<= sfinal)

        cylinder { <xpos(s), ypos(s), zpos(s)>, <xpos(s+ds), ypos(s+ds),
                        zpos(s+ds)>, .1 

        texture{mrg_green_texture}
        pigment {          // (---surface color---)

                        color rgbt <.0,.5,.0>

                        }}

        #declare s = s+ds;           //modify s with each loop of while loop                        
        #declare source_point=<xpos(s), ypos(s), zpos(s)>;    
        #end