encoding  utf-8
layout symbols

symbol-assign line wall:debris AUT

code metapost


def l_u_rail (expr P) = 
  T:=identity;
  cas := 0;
  dlzka := arclength P;
  mojkrok:=adjust_step(dlzka, 0.8u);
  pickup PenC;
  forever:
    t0 := arctime (cas) of P;
    t1 := arctime (cas + mojkrok*2/5) of P;
    t  := arctime (cas + mojkrok/2) of P;
    t4 := arctime (cas + mojkrok*3/5) of P;
    t5 := arctime (cas + mojkrok) of P;
    thdraw (subpath (t0,t1) of P);
    thdraw (subpath (t4,t5) of P);
    drawdot
       (point t of P);
    #mark_ (P,t,0.02u);
    #mark_ (P,t,-0.02u);
     #f := (P,t,0.2u);
     #draw f;
    cas := cas + mojkrok;
    exitif cas > dlzka - (2*mojkrok/3); % for rounding errors
  endfor;
enddef;


initsymbol("l_u_rail")
#text en line u:rail "Railing"

              
      def a_debris_CHED (expr p) =
      T:=identity;
      pickup PenC;
      path q, qq; q = bbox p;
      picture tmp_pic; 
      tmp_pic := image(
        for i = xpart llcorner q step u until xpart urcorner q:
         for j = ypart llcorner q step u until ypart urcorner q:
            qq := punked 
  (((-.2u,-.2u)--(.2u,-.2u)--(.2u,.2u)--(-.2u,.2u)--cycle) 
         randomized (u/2))
               rotated uniformdeviate(360) 
               shifted ((i,j) randomized u);
       if xpart (p intersectiontimes qq) < 0:
        thclean qq;
        thdraw qq;
       fi;
          endfor;  
        endfor;
      );
      clip tmp_pic to p;
      draw tmp_pic;
    enddef;
    
      def a_sand_CHED(expr p) =
        T:=identity;
        %  thclean p;
        pickup PenC;
        path q; q = bbox p;
        picture tmp_pic; 
        tmp_pic := image(
          for i = xpart llcorner q step .3u until xpart urcorner q:
            for j = ypart llcorner q step .3u until ypart urcorner q:
              draw origin shifted ((i,j) randomized 0.2u) withpen PenC;
            endfor;  
          endfor;
        );
        clip tmp_pic to p;
        draw tmp_pic;
      enddef;
      
      def l_flowstone_CHED (expr P) = 
  T:=identity;
  cas := 0;
  dlzka := arclength P;
  mojkrok:=adjust_step(dlzka, .25u);
  pickup PenC;  
  t1:=0;
  forever:
    t2 := arctime (cas + mojkrok) of P;
    thdraw (point t1 of P){dir (angle(thdir(P,t1)) + 60)} ..
           {dir (angle(thdir(P,t2)) - 60)}(point t2 of P);
    cas := cas + mojkrok;
    exitif cas > dlzka + (mojkrok / 3); % for rounding errors
    t1:=t2;
  endfor;
enddef;

def l_overhang_CHED (expr P) =
# taken from: def l_ceilingstep_SKBB (expr P) =
  T:=identity;
  cas := 0;
  dlzka := arclength P;
  #controls the length
  mojkrok:=adjust_step(dlzka, 0.3u);
  pickup PenC;
  forever:
    t1 := arctime (cas + mojkrok*1/5) of P;
    t  := arctime (cas + mojkrok/2) of P;
    t2 := arctime (cas + mojkrok*4/5) of P;
    thdraw (subpath (t1,t2) of P);
    #controls the lengthof the tick
    mark_ (P,t,0.15u);
    cas := cas + mojkrok;
    exitif cas > dlzka - (2*mojkrok/3); % for rounding errors
  endfor;
enddef;

 def l_pit_CHED (expr P) = 
  T:=identity;
  cas := 0;
  dlzka := arclength P;
  mojkrok:=adjust_step(dlzka, 0.1u);
  pickup PenD;  
  forever:
    t := arctime cas of P;
    mark_ (P,t,0.1u);
    cas := cas + mojkrok;
    exitif cas > dlzka + (mojkrok / 3); % for rounding errors
  endfor;
  pickup PenC;  
  thdraw P;
enddef; 



initsymbol ("l_flowstone_CHED");
initsymbol ("l_pit_CHED");
initsymbol ("l_overhang_CHED");

    initsymbol ("a_sand_CHED");
    initsymbol ("a_debris_CHED");
    
def l_wall_blocks_CHED (expr P) = 

%  pickup PenD;
%  draw P withcolor red;

  T:=identity;
  cas := 0;
  dlzka := arclength P;
if dlzka > 0:
  mojkrok:=adjust_step(dlzka, .9u);
  pickup PenB;
  forever:
    t1 := arctime (cas + mojkrok*1/10) of P;
    t2 := arctime (cas + mojkrok*9/10) of P;
    q := ((point t1 of P) + .2u * unitvector(thdir(P,t1) rotated -90)) --
         (subpath (t1,t2) of P) --
         ((point t2 of P) + .2u * unitvector(thdir(P,t2) rotated -90));
    thdraw q randomized (u/6);
    cas := cas + mojkrok;
    exitif cas > dlzka - (2*mojkrok/3); % for rounding errors
  endfor;
fi;
enddef;

    initsymbol ("l_wall_blocks_CHED");

#derived from def l_pit_UIS (expr P) =     
    def l_floorstep_CHED (expr P) = 
  T:=identity;
  cas := 0;
  dlzka := arclength P;
 # Step leangth changed from 0.25
  mojkrok:=adjust_step(dlzka, 0.12u);
  pickup PenD;  
  forever:
    t := arctime cas of P;
 #length of tck shorted pit was 0.2
    mark_ (P,t,0.1u);
    cas := cas + mojkrok;
    exitif cas > dlzka + (mojkrok / 3); % for rounding errors
  endfor;
  pickup PenC;  
  thdraw P;
enddef;

    initsymbol ("l_floorstep_CHED");
     
    
endcode

    symbol-assign area blocks AUT
    symbol-assign area debris CHED
    symbol-assign area sand CHED
    
    symbol-assign line flowstone CHED
    symbol-assign line overhang CHED
    symbol-assign line pit CHED
    symbol-assign line wall:blocks CHED
    symbol-assign line floor-step CHED




endlayout