// By Chung-Chih Li, Nov. 19, 2002
// This program uses CMU Graphics library.
#include <iostream>
using namespace std; 

#include <CMUgraphics.h>
#include <cmath> 

int W_Width=1000;
const double PI = 3.141592653589793238462643383279;

class point
{
friend class triangle;
public:
    point();
    point(double x, double y);
    double x() const;
    double y() const;
    double distance(point & p) const;
private:
    double my_x;
    double my_y;
};

class triangle
{
public:
    triangle();
    triangle(point a, point b, point c);
    point p1();
    point p2();
    point p3();
	void set_color(int color);
    void shift(point v);
    double area();
    point center();
    triangle rotate(double theta);               // use default center
    triangle rotate(double theta, point C); // use c as center;  void shift(point v);
private:
    point my_p1;
    point my_p2;
    point my_p3;
	int my_color;
    point rotate_oneP(double theta, point P,  point center);
};


point::point()
:my_x(0), my_y(0)
{
}

point::point(double x, double y)
:my_x(x), my_y(y)
{
}

double point::x() const
{
    return my_x;
}

double point::y() const
{
    return my_y;
}

double point::distance(point & p) const
{
    return sqrt(pow(my_x-p.my_x,2)+pow(my_y-p.my_y,2));
}



triangle::triangle()
:my_p1(point(0,0)), my_p2(point(0,0)), my_p3(point(0,0)),my_color(0)
{}

triangle::triangle(point a, point b, point c)
:my_p1(a), my_p2(b), my_p3(c),my_color(0)
{}


point triangle::p1()
{
    return my_p1;
}

point triangle::p2()
{
    return my_p2;
}

point triangle::p3()
{
    return my_p3;
}



void triangle::shift(point v)
{
    my_p1.my_x += v.x();
    my_p1.my_y += v.y();
    my_p2.my_x += v.x();
    my_p2.my_y += v.y();
    my_p3.my_x += v.x();
    my_p3.my_y += v.y();
}


double triangle::area()
{
    double a,b,c,s,Area;
    a = my_p1.distance(my_p2);
    b = my_p2.distance(my_p3);
    c = my_p3.distance(my_p1);
    s = (a+b+c)/2;
    Area = sqrt(s*(s-a)*(s-b)*(s-c));
    return Area;
}

point triangle::center()
{
    double x,y;
    x = (my_p1.my_x+my_p2.my_x+my_p3.my_x)/3.0;
    y = (my_p1.my_y+my_p2.my_y+my_p3.my_y)/3.0;
    return point(x,y);
}




void triangle::set_color(int color)
{
    my_color=color;
}


triangle triangle::rotate(double theta)   // use default center 
{
    point C = center();
    my_p1 = rotate_oneP(theta, my_p1, C);
    my_p2 = rotate_oneP(theta, my_p2, C);
    my_p3 = rotate_oneP(theta, my_p3, C);
    return triangle(my_p1,my_p2,my_p3);
}

triangle triangle::rotate(double theta, point C) // use c as center;
{
    my_p1 = rotate_oneP(theta, my_p1, C);
    my_p2 = rotate_oneP(theta, my_p2, C);
    my_p3 = rotate_oneP(theta, my_p3, C);

    return triangle(my_p1,my_p2,my_p3);
}

point triangle::rotate_oneP(double theta, point P, point C)
{
    double x = P.x() - C.x();
    double y = P.y() - C.y();
    double r = P.distance(C);
    double beta;
    
    if ( x<= 0.0000001 && x >= -0.0000001) 
        beta=3.1415926/2;
    else 
        beta = atan(y/x);

    if (x < -0.0000001)
        beta = beta+3.1415926;
    beta -= theta;
    x = r*cos(beta);
    y = r*sin(beta);

    return point(x+C.x(),y+C.y());
}


void drawT(window *W, triangle T)
{
	W->DrawLine(T.p1().x(), T.p1().y(), T.p2().x(), T.p2().y());
	W->DrawLine(T.p2().x(), T.p2().y(), T.p3().x(), T.p3().y());
	W->DrawLine(T.p3().x(), T.p3().y(), T.p1().x(), T.p1().y());
//    W->DrawLine(T.center().x(), T.center().y(), T.center().x()+1, T.center().y()+1);
}



void main()
{
    window *GWin;
    int x,y;
	int Font_size = 20, GWin_X_Width, GWin_Y_Width;
	double theta;
	
    cout << "Input Window Width (400-2800):";
    cin >> x;
//	x= 600;
	W_Width=x;
    GWin_X_Width=W_Width;
    GWin_Y_Width= GWin_X_Width*3/4;

    point a(0,GWin_Y_Width-20);
	point b(GWin_X_Width/5,GWin_Y_Width-GWin_X_Width/10);
	point c(GWin_X_Width/4,GWin_Y_Width-20);
	triangle Tri(a,b,c);


        
	cout << "Click on the " <<  GWin_X_Width << "X" 
		 <<  GWin_Y_Width << " Window to activate." << endl;

    window LocalWin(GWin_X_Width, GWin_Y_Width, 0, 0);

    GWin = &LocalWin;

    GWin->SetWaitClose(false);
    GWin->ChangeTitle("Rotation in CMU Graphics Windows C.C.L.");
    GWin->WaitMouseClick(x,y);
    x=y=0;
    GWin->SetFont(Font_size,1,ROMAN);
    
	GWin->SetPen(0.0, 0.0, 1.0);
    GWin->SetFont(Font_size,1,ROMAN);
  
	drawT(GWin, Tri);
	GWin->WaitMouseClick(x,y);

	x=y=0;

    double g=-0.01, steps=500;
    double hv = GWin_X_Width/steps;
    double vv= -g*(GWin_X_Width/3), vs=0;
    double d_theta = -0.05;
	point s;

	double i=0;
	while (Tri.center().y() <= GWin_Y_Width-20)
	{
	  i = i+hv;
      s = point(hv,vs-(vv*i+g*i*i/2));
	  vs = (vv*i+g*i*i/2);	  
	  Tri.shift(s);
	  Tri.rotate(d_theta);
	  drawT(GWin, Tri);
      GWin->GetMouseClick(x,y);
        if ( x >= 0)
        {
			Sleep(20);
   	        GWin->WaitMouseClick(x,y);
		}
		else Sleep(20);
	}

	GWin->WaitMouseClick(x,y);
}