CGR Ass 2

#include <iostream>
#include <algorithm>
#include <graphics.h>
#include <cmath>
using namespace std;

class ScanLine {
public:
    int x[20], y[20], k;
    float slope[20], x_int[20];

    void polygon(int n){
        int i;
        float dx, dy;

        // Make First and Last Points of the Polygon the same
        x[n] = x[0];
        y[n] = y[0];

        // Draw Lines
        for (int i = 0; i < n; i++){
            line(x[i], y[i], x[i + 1], y[i + 1]);
        }

        // Get Slopes of each Line
        for (int i = 0; i < n; i++){
            dy = y[i + 1] - y[i];
            dx = x[i + 1] - x[i];
            if (dy == 0) slope[i] = 1;
            else if (dx == 0) slope[i] = 0;
            else slope[i] = dx/dy;
        }

        // Find Intersection Points
        for (int p = 0; p < 512; p++) {
            k = 0;
            for (int i = 0; i < n; i++){
                if ( ((y[i] <= p) && (y[i + 1] > p)) || ((y[i] > p) && (y[i + 1] <= p) )) {
                    x_int[k] = x[i] + slope[i] * (p - y[i]);
                    k++;
                }
            }

            // Sort (WHy THIS NOT WORKY!! :(( )
            // int ok = sizeof(x_int)/sizeof(x_int[0]);
            // sort(x_int, x_int+ok);

            // Bubble sort
            for (int j = 0; j < k-1; j++){
                for (int i = 0; i < k-1; i++){
                    if (x_int[i] > x_int[i+1]){
                        int temp = x_int[i];
                        x_int[i] = x_int[i+1];
                        x_int[i+1] = temp;
                    }
                }
            }

            for (int i = 0; i < k; i+=2){
                setcolor(YELLOW);
                line(x_int[i], p, x_int[i+1], p);
                delay(30);

            }
        }

    }

};

int main(){


    int n, i;
    ScanLine P;
    cout << "Enter the number of Edges: "; cin >> n;
    cout << "Enter the co-ordinates: " << endl;
    for (int i = 0; i < n; i++){
        cin >> P.x[i] >> P.y[i];
    }

    int gd = DETECT; int gm;
    initgraph(&gd, &gm, nullptr);

    P.polygon(n);

    getch();
    closegraph();

    return 0;
}


/*

Enter the number of Edges: 3
Enter the co-ordinates:
300 50
500 250
100 400

*/