#include <cmath>
#include <vector>

using namespace std;

const float fps = 0.01;

struct P {
    float x;
    float y;
    float vx;
    float vy;
    float m;
};

vector<P> p;

void display() {
    glClear(GL_COLOR_BUFFER_BIT);
    for (vector<P>::iterator i = p.begin(); i != p.end(); ++i) {
        if (i->m <= 2) {
            glPointSize(2);
            glBegin(GL_POINTS);
            glVertex2f(i->x, i->y);
            glEnd();
        } else {
            glBegin(GL_LINES);
            for (int a = 0; a < 36; ++a) {
                float x = i->m * cos(a * 3.14 / 18);
                float y = i->m * sin(a * 3.14 / 18);
                glVertex2f(i->x + x, i->y + y);
                x = i->m * cos((a + 1) * 3.14 / 18);
                y = i->m * sin((a + 1) * 3.14 / 18);
                glVertex2f(i->x + x, i->y + y);
            }
            glEnd();
        }
    }
    glutSwapBuffers();
}

void timer(int = 0) {
    for (vector<P>::iterator i = p.begin(); i != p.end(); ++i)
        for (vector<P>::iterator j = p.begin(); j != p.end(); ++j)
            if (i != j) {
                float d = sqrt((i->x - j->x) * (i->x - j->x) +
                               (i->y - j->y) * (i->y - j->y));
                if (d < i->m + j->m) {
                    float f = 50 * (i->m + j->m - d);
                    i->vx += f * (i->x - j->x) / d / i->m * fps;
                    i->vy += f * (i->y - j->y) / d / i->m * fps;
                    j->vx -= f * (i->x - j->x) / d / j->m * fps;
                    j->vy -= f * (i->y - j->y) / d / j->m * fps;
                }
            }
    for (vector<P>::iterator i = p.begin(); i != p.end(); ++i) {
        i->x += i->vx * fps;
        i->y += i->vy * fps;
        if (i->x < 0)
            i->x += 480;
        if (i->y < 0)
            i->y += 480;
        if (i->x > 480)
            i->x -= 480;
        if (i->y > 480)
            i->y -= 480;
    }
    display();
    glutTimerFunc(10, timer, 0);
}

int main(int argc, char **argv) {
    P p0 = {480 / 2, 480 / 2, 0, 0, 40};
    p.push_back(p0);
    for (int i = 0; i < 100; ++i) {
        P p0 = {rand() % 480, rand() % 480, rand() % 100000 / 500.0 - 100,
                rand() % 100000 / 500.0 - 100, 4};
        p.push_back(p0);
    }
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowSize(480, 480);
    glutInitWindowPosition(20, 1050 - 480 - 20);
    glutCreateWindow("Молекулы");
    glClearColor(0, 0, 0, 1.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0, 480, 480, 0, -1, 1);
    glutDisplayFunc(display);
    timer();
    glutMainLoop();
}