// CORES E TEXTURAS

#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 }
  }

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

// DESCRIÇÃO DA CENA 

#macro CriaCurva(raio)
  #declare curva =
  spline { natural_spline
    -0.25, < 0.0,-5.0,-1.0>,
    0.00, < 0.0, 0.0, 0.0>,
    0.25, < 0.0, 5.0, 4.0>,
    0.50, < 1.5, 6.0,12.0>,
    0.75, < 8.0, 4.0,18.5>,
    1.00, <15.0, 5.0,20.0>,
    1.25, <20.0, 5.0,19.4>
  }
#end

#macro InterpolacaoLinear(x0, y0, x1, y1, tt)
  #local delta = x1 - x0;
  #local r = (tt - x0)/delta;
  #local s = 1 - r;
  #local vv = s*y0 + r*y1;
  vv
#end

#macro arcobevier(t0, t1, A, B, C ,D, tt)
  #local AB = InterpolacaoLinear(t0, A.y, t1, B.y, tt);
  #local BC = InterpolacaoLinear(t0, B.y, t1, C.y, tt);
  #local CD = InterpolacaoLinear(t0, C.y, t1, D.y, tt);

  #local ABC = InterpolacaoLinear(t0, AB, t1, BC, tt);
  #local BCD = InterpolacaoLinear(t0, BC, t1, CD, tt);
  #local ABCD = InterpolacaoLinear(t0, ABC, t1, BCD, tt);
 
  ABCD
#end

#macro suavizaZ(P, N, i, vv)
  #local j = mod(i+i, N);
  #declare P[i][2] = P[i][3] - vv;
  #declare P[j][2] = P[j][0] + vv;
#end


#macro suavizaX(P, N, i)
  #local j = mod(i+i, N);
  #local vv = (P[j][i] - P[i][2])/2; 
  suavizaZ(P, N, i, vv)
#end

#macro palito(R, A, B, C, D, t0, t1, uu)
  #local palto = union {
  #local tt = t0.x;
  #while (tt < t1.x)
    sphere{ <0,0,0>, R 
      pigment { color rgb<1,0.3,0>} 
      translate <tt, arcobevier(t0.x, t1.x, A, B, C, D, tt), t1.z>
    }
    #local tt = tt + uu;
  #end
  }
  palto
#end

#macro CriaNo(n_voltas, raio_corda, espacamento_entre_bolas)
  #declare uu = 0.07;
  #declare bolas = 10;

  #declare n_arcos = 3;
  #declare n_curvas = 4;
  #declare arcos = array[n_arcos][n_curvas];
  #declare arcos[0][0] = <1, 3, 5>;
  #declare arcos[0][1] = <1, 5, 0>;
  #declare arcos[0][2] = <4, 5, 5>;
  #declare arcos[0][3] = <4, 3, 0>;
  #declare arcos[1][0] = <4, 3, 5>;
  #declare arcos[1][1] = <4, 0, 0>;
  #declare arcos[1][2] = <10, 0, 5>;
  #declare arcos[1][3] = <10, 3, 0>;
  #declare arcos[2][0] = <15, 3, 0>;
  #declare arcos[2][1] = <10, 20, 5>;
  #declare arcos[2][2] = <15, 20, 0>;
  #declare arcos[2][3] = <10, 3, 5>;

  suavizaX(arcos, n_arcos, 0);
  suavizaX(arcos, n_arcos, 1);
  suavizaX(arcos, n_arcos, 2);

  union {
  #declare i = 0;
  #while (i < n_arcos)
    object { palito(raio_corda, arcos[i][0],
				arcos[i][1],
                                arcos[i][2],
                                arcos[i][3],
                                arcos[i][0],
                                arcos[i][3], uu) }
    #declare i = i + 1;
  #end
  }

#end 

CriaNo(5, 0.7, 1)

#include "camlight.inc"
#declare centro_cena = < 0.00, 0.00, 0.00 >;
#declare raio_cena = 30.0;
#declare dir_camera = < 10.00, 10.00, 10.00 >;
#declare dist_camera = 2*raio_cena;
#declare intens_luz = 1.20;
camlight(centro_cena, raio_cena, dir_camera, dist_camera , y, intens_luz)