// CORES E TEXTURAS

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


#declare tx_grey = 
  texture{
    pigment{ color rgb < 0.6, 0.6, 0.7 > }
    finish{ diffuse 0.8 ambient 0.1 specular 0.5 roughness 0.005 }
  }

// ======================================================================		
// MACROS

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


#macro arco_bezier(t0, t1, tt, A, B, C, D) 
	#local AB = interpola(t0, A, t1, B, tt);
	#local BC = interpola(t0, B, t1, C, tt);
	#local CD = interpola(t0, C, t1, D, tt);
	
	#local ABC = interpola(t0, AB, t1, BC, tt);
	#local BCD = interpola(t0, BC, t1, CD, tt);

	#local ABCD = interpola(t0, ABC, t1, BCD, tt);
	ABCD
#end

// ======================================================================
// CONSTRUCAO DA CENA

//object{ gerar_quadrado(1)}
//object{ gerar_circulo(1, 1, 0.5)}
#declare length = 10;
#declare tt_ = -length;
#while(tt_ < length)
	//object{ sphere{<0, 0, 0>, 0.5 texture{tx_grey}} translate interpola(-1, <-1, -1, -1>, 1, <1, 1, 1>, tt_)}
	object{ sphere{<0,0,0>, 0.5 texture{tx_grey}} translate arco_bezier(-length, length, tt_, <0,0,0>, <length,0,0>, <length,length,0>, <0,length,0>)}
	#declare tt_ = tt_ + 0.1;
#end

#local PEA = <3,5,7>;
#local VEA = <-2,2,0>;
#local PAB = <5,8,10>;
#local VAB = <1,-3,2>;
#local A1 = PEA;
#local A2 = A1-VEA;
#local A4 = PAB;
#local A3 = A4-VAB;

// ======================================================================
// CAMERA E ILUMINACAO:

#include "camlight.inc"
#declare centro_cena = < 0.00, 0.00, 0.00 >;
#declare raio_cena = 20;
#declare dir_camera = < 0.00, 2.00, 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)