// Exemplo de arquivo de descricao de cena para POV-ray
// Last edited on 2017-05-07 20:10:09 by stolfilocal

// ======================================================================
// CORES E TEXTURAS

background{ color rgb < 0.75, 0.80, 0.85 > }

#declare tx_plastico = 
  texture{
    pigment{ color rgb < 0.10, 0.80, 1.00 > }
    finish{ diffuse 0.8 ambient 0.1 specular 0.5 roughness 0.005 }
  }

#declare tx_fosca = 
  texture{
    pigment{ color rgb < 1.00, 0.80, 0.10 > }
    finish{ diffuse 0.9 ambient 0.1 }
  }

#declare tx_peca = 
  texture{
    pigment{ color rgb < 0.5, 0.5, 0.5 > }
    finish{ diffuse 0.9 ambient 0.1 }
  }

#declare tx_espelho = 
  texture{
    pigment{ color rgb < 1.00, 0.85, 0.30 > }
    finish{ diffuse 0.2 reflection 0.7*< 1.00, 0.85, 0.30 > ambient 0.1 }
  }

#declare tx_vidro = 
  texture{
    pigment{ color rgb < 0.85, 0.95, 1.00 > filter 0.70 }
    finish{ diffuse 0.03 reflection 0.25 ambient 0.02 specular 0.25 roughness 0.005 }
  }


#declare tx_xadrez =
  texture{
    pigment{ checker color rgb < 0.0, 0.0, 0.0 >, color rgb < 1.00, 0.97, 0.90 > }
    finish{ diffuse 0.9 ambient 0.1 }
    scale 1.0
  }

// ======================================================================
// DESCRIÇÃO DA CENA 
#include "eixos.inc"

#macro interpolalin(t0, v0, t1, v1, tt)
  #local r = (tt-t0)/(t1-t0);
  #local s = 1 - r;
  #local vv = s*v0 + r*v1;
  vv
#end

#macro arcobezier(t0, t1, A, B, C, D, tt)
  #local AB = interpolalin(t0, A, t1, B, tt);
  #local BC = interpolalin(t0, B, t1, C, tt);
  #local CD = interpolalin(t0, C, t1, D, tt);
  
  #local ABC = interpolalin(t0, AB, t1, BC, tt);
  #local BCD = interpolalin(t0, BC, t1, CD, tt);
  
  #local ABCD = interpolalin(t0, ABC, t1, BCD, tt);
  
  ABCD
#end

#declare lado = 40;
#declare n_arcos = 4;
#declare n_bolas = 1500;
#declare grossura = 1;
#declare tx = tx_fosca;

#macro suaviza(P, n_arcos, i)
  #local j = mod(i+1, n_arcos);
  #local vv = (P[j][1] - P[i][2])/2;
  #declare P[i][2] = P[i][3] - vv;
  #declare P[j][1] = P[j][0] + vv;
#end

#macro Corda(grossura, lado, n_arcos, n_bolas, tx)
  #declare tt = 0;
  #declare P = array[n_arcos][4];

  #declare P[0][0] = <0,0,0>;
  #declare P[0][1] = <0.25,0,0.5>;
  #declare P[0][2] = <.7,0,.7>;
  #declare P[0][3] = <.5,0,.25>;
  #declare P[1][0] = P[0][3];
  #declare P[1][1] = <-0.2,0,-0.8>;
  #declare P[1][2] = <-0.7,-.5,-0.5>;
  #declare P[1][3] = <-0.2,0,.6>;
  #declare P[2][0] = P[1][3];
  #declare P[2][1] = <1,.5,0>;
  #declare P[2][2] = <0,2,-.5>;
  #declare P[2][3] = <0.5,0,.4>;
  #declare P[3][0] = P[2][3];
  #declare P[3][1] = <1,0.8,-1>;
  #declare P[3][2] = <0,0.4,-0.2>;
  #declare P[3][3] = P[0][0];
    
  #declare i = 0;
  #while (i < n_arcos)
    suaviza(P, n_arcos, i)
    #declare i = i + 1;
  #end

  #declare i = 0;
  #declare j = 0;
  #while (j < n_bolas)
    #if ((tt >= i/n_arcos) & (tt < (i + 1)/n_arcos))
      #declare centro = arcobezier(i/n_arcos, (i + 1)/n_arcos, P[i][0], P[i][1], P[i][2], P[i][3],tt); 
      #declare tt=tt+1/n_bolas;
      #declare j=j+1;
      sphere{ lado*centro, grossura texture {tx} }
	#else
	  #declare i=i+1;
    #end 
  #end  
#end

Corda(grossura, lado, n_arcos, n_bolas, tx)



#include "camlight.inc"
#declare centro_cena = < 6, 0, 0 >;
#declare raio_cena = 50;
#declare dir_camera = < 10.00, 30.00, 5.00 >;
#declare dist_camera = 5*raio_cena;
#declare intens_luz = 1.20;
camlight(centro_cena, raio_cena, dir_camera, dist_camera , z, intens_luz)