include iostream include stack include stdlib include glut include tim

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#include <iostream>
#include <stack>
#include <stdlib.h>
#include "glut.h"
#include <time.h>
using namespace std;
struct Point
{
int x;
int y;
};
Point *points;
Point *pp;
int n, k = 0;
Point p0;
stack<Point> S;
Point nextToTop(stack<Point> &S)
{
Point p = S.top();
S.pop();
Point res = S.top();
S.push(p);
return res;
}
void swap(Point &p1, Point &p2)
{
Point temp = p1;
p1 = p2;
p2 = temp;
}
int dist(Point p1, Point p2)
{
return (p1.x - p2.x)*(p1.x - p2.x) + (p1.y - p2.y)*(p1.y - p2.y);
}
int orientation(Point p, Point q, Point r)
{
int val = (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y);
if (val == 0) return 0;
return (val > 0)? 1: 2;
}
int compare(const void *vp1, const void *vp2)
{
Point *p1 = (Point *)vp1;
Point *p2 = (Point *)vp2;
int o = orientation(p0, *p1, *p2);
if (o == 0)
return (dist(p0, *p2) >= dist(p0, *p1))? -1 : 1;
return (o == 2)? -1: 1;
}
void convexHull()
{
int ymin = points[0].y, min = 0;
for (int i = 1; i < n; i++)
{
int y = points[i].y;
if ((y < ymin) || (ymin == y && points[i].x < points[min].x))
ymin = points[i].y, min = i;
}
swap(points[0], points[min]);
p0 = points[0];
qsort(&points[1], n-1, sizeof(Point), compare);
S.push(points[0]);
S.push(points[1]);
S.push(points[2]);
for (int i = 3; i < n; i++)
{
while (orientation(nextToTop(S), S.top(), points[i]) != 2)
S.pop();
S.push(points[i]);
}
int i = 0;
cout << endl << "Точки выпуклой оболочки:" << endl;
while (!S.empty())
{
Point p = S.top();
cout << p.x << "\t" << p.y << endl;
pp[i] = p;
S.pop();
++i;
k++;
}
cout << endl << "Количество точек выпуклой оболочки: " << k << endl << endl;
}
void show(){
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_LINE_LOOP);
for (int i = 0 ; i < k; i++)
{
glColor3f(0, 1, 0);
glVertex2f(pp[i].x, pp[i].y);
}
glEnd();
glColor3f(1, 1, 1);
for (int i = 0; i < n; i++)
{
glBegin(GL_TRIANGLE_FAN);
glVertex2f(points[i].x, points[i].y);
float r = 2;
for (float phi = 0; phi <= 6.30; phi += 0.1)
{
float x0 = r * cos(phi);
float y0 = r * sin(phi);
glVertex2f(x0 + points[i].x, y0 + points[i].y);
}
glEnd();
}
glutSwapBuffers();
}
int main(int argc, char **argv)
{
setlocale(LC_ALL,"Rus");
cout << "Алгоритм Грэхема:" << endl;
cout << "Количество точек на плоскости: ";
cin >> n;
points = new Point [n];
pp = new Point [n];
srand(time(NULL));
for(int i = 0; i < n; i++){
points[i].x=rand()%550+30;
points[i].y=rand()%350+30;
}
for(int i = 0; i < n; i++){
cout<<points[i].x<<"\t";
cout<<points[i].y<<endl;
}
convexHull();
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize(600, 400);
glutCreateWindow("Graham");
glClearColor(0,0,0,0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 600, 400, 0, -1, 1);
glutDisplayFunc(show);
glutMainLoop();
delete []points;
delete []pp;
return 0;
}