#include "library.h"

const double pi = acos(-1.0);

double distance(double ax, double ay,
                double bx, double by)
{ return sqrt((ax-bx)*(ax-bx) + (ay-by)*(ay-by)); }

double random_in_range(double a, double b)
{ return random_in_range((int)(a * 10000), (int)(b * 10000)) / 10000.0; } 

double random_angle(double mindeg, double maxdeg)
{ return random_in_range(mindeg, maxdeg) * pi / 180; } 

void trunk(double p1x, double p1y,
           double p2x, double p2y,
           double beta,
           double len,
           double taper)
{ double base = distance(p1x, p1y, p2x, p2y);
  double alpha = direction_from_to_in_radians(p1x, p1y, p2x, p2y) - pi/2;
  if (sin(beta) > 2 * len / base)
  { print("Bad sin(beta)\n");
    return; }
  double p3x = (p1x + p2x) / 2,
         p3y = (p1y + p2y) / 2;
  double p4x = p3x + len * sin(alpha + beta),
         p4y = p3y - len * cos(alpha + beta);
  double end = base * taper;
  double g = pi/2 - alpha - beta;
  double p5x = p4x - 0.5 * end * sin(g),
         p5y = p4y - 0.5 * end * cos(g);
  double p6x = p4x + 0.5 * end * sin(g),
         p6y = p4y + 0.5 * end * cos(g);
  move_to(p1x, p1y);
  draw_to(p5x, p5y);
  draw_to(p6x, p6y);
  draw_to(p2x, p2y);
  draw_to(p1x, p1y); }

void main()
{ 
  make_window(800, 800);
  trunk( 50, 780,   150, 780,  0,          700,  0.5);
  trunk(250, 780,   350, 780,  15*pi/180,  700,  0.5);
  trunk(550, 780,   650, 720,  20*pi/180,  300,  0.3); 
}