//Tp05 by Carlos Robson
// ======================================================================

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

#declare Yellow = rgb<255, 255, 0>;
#declare Black =  rgb < 0.4, 0.4, 0.4 >;

#declare tx_plastico = 
  texture{
    pigment{ color rgb < 0.4, 0.4, 0.4 > }
    finish{ diffuse 0.8 ambient 0.1 specular 0.5 roughness 0.005 }
  }
  
#declare esfera =
	sphere {
		< 0, 0,  0>, 0.25 // Near lower left corner
		 texture{ tx_plastico }
	}

#macro interpola(to, vo, t1, v1, tt )
	#local r = (tt-to)/(t1-to);
	#local s = 1-r;
	#local vv= s*vo+r*v1;
	vv
#end

#macro arcobezier(to, t1, a, b, c, d, tt )
	#local ab = interpola(to, a, t1, b, tt );
	#local bc = interpola(to, b, t1, c, tt );
	#local cd = interpola(to, c, t1, d, tt );	
	#local abc = interpola(to, ab, t1, bc, tt );
	#local bcd = interpola(to, bc, t1, cd, tt );
	#local abcd = interpola(to, abc, t1, bcd, tt );
	abcd
#end

#macro desenhaBezier(A,B,C,D)
		#for (j, 0, 1, 0.001)
			object { esfera translate arcobezier(0,1,A,B,C,D,j) }
		#end
#end

#macro suavizaX(P,N,i)
 //Suaviza a junta entre o arco
 //i e o arco = mod(i+1,N)
#local j = mod(i+1,N);
#local vv = (P[j][i] - P[i][2])/2;
#declare P[i][2] = P[i][3]-vv;
#declare P[j][1] = P[j][0]+vv;

#end

#macro curva()
#declare P = array[3][4];

#declare P[0][0] = <0,-3,2>;
#declare P[0][1] = <-1,2,-3>;
#declare P[0][2] = <-3,0,2>;
#declare P[0][3] = <1,1,2>;

#declare P[1][0] = <1,1,2>;
#declare P[1][1] = <2,0,-3>;
#declare P[1][2] = <0,-2,0>;
#declare P[1][3] = <3,0,2>;

#declare P[2][0] = <3,0,2>;
#declare P[2][1] = <3,-2,-1>;
#declare P[2][2] = <-1,-3,2>;
#declare P[2][3] = <0,-3,2>;

	//[<0,2,-3>,<1,0,-2>,<1,0,2>,<1,0,1>]
	
	suavizaX(P,2,0)
	suavizaX(P,2,1)
	suavizaX(P,2,2)

	union
	{
		desenhaBezier(P[0][0],P[0][1],P[0][2],P[0][3])
		desenhaBezier(P[1][0],P[1][1],P[1][2],P[1][3])
		desenhaBezier(P[2][0],P[2][1],P[2][2],P[2][3])
	}
#end


	
  
// ======================================================================
// DESCRIÇÃO DA CENA 

#include "eixos.inc"

object{ eixos(3.00) }

object{ curva() }

#include "camlight.inc"
#declare centro_cena = < 0.00, 0.00, 1.00 >;
#declare raio_cena = 4;
#declare dir_camera = < 14.00, 7.00, 4.00 >;
#declare dist_camera = 5*raio_cena;
#declare intens_luz = 1.20;
camlight(centro_cena, raio_cena, dir_camera, dist_camera , z, intens_luz)