Creating Butterfly themed Fractal in C++ Using Graphics

// C++ code to Create a Butterfly 
// themed Fractal using Graphics

#include <math.h>
#include <stdlib.h>
#include <winbgim.h>

#define Y 1080
#define X 1920

// c is defined as the angle between each
// iterative lines, changing this would result
// in different and interesting patterns.
#define c 5 * M_PI / 7

// colorVal is used to provide different colors
// for each iterating point/line in the cycle.
int colorVal = 0;

// The core function in the program which is
// recursive in nature and terminates when the
// line size is less than 0.1 pixels.
int Pyt_Tree(float x, float y, float r, float ang)
{

    // Max iteration condition so as to increase
    // the accuracy of the fractal pattern.
    // The closer it is to zero the higher the
    // details but would cost more processing time.
    if (r < 0.1) {

        // combination of type casting and iteration
        // so as to provide a Greatest Integer Function
        // sort of manipulation for the color input.
        setcolor((colorVal++ % 15000) / 1000 + 1);

        // Conversion of the parametric coordinates
        // of the points to the Argand coordinates
        // while displaying them.
        line(x, y, x - r * sin(ang), y - r * cos(ang));

        return 0;
    }

    float r_n;

    if (c > M_PI / 4) {
        r_n = sin(c);
    }
    else {
        r_n = cos(c);
    }

    // Recursive calling of the Pyt_Tree() function
    // to get towards the end of the branch of the
    // fractal tree.
    Pyt_Tree(x - r * sin(ang), y - r * cos(ang),
             r / (2 * r_n), (ang + c));
    Pyt_Tree(x - r * sin(ang), y - r * cos(ang),
             r / (2 * r_n), (ang - c));

    return 0;
}

// Driver code
int main()
{
    initwindow(X, Y);
    Pyt_Tree(X / 2, Y, Y * 0.9, 0);
    getch();
    closegraph();
    return 0;
}