C Program to implement 3-D rotation with respect to x-axis, y-axis and z-axis

#include <stdio.h>
#include <graphics.h>
#include <math.h>
#include <stdlib.h>
#include <dos.h>
#include <conio.h>
 
#define ORG -50
 
double face1[5][2] = {
{ 250, 125 },
{ 350, 125 },
{ 350, 225 },
{ 250, 225 },
{ 250, 125 }
};
 
double face2[5][2] = {
{ 250+ORG, 125-ORG },
{ 350+ORG, 125-ORG },
{ 350+ORG, 225-ORG },
{ 250+ORG, 225-ORG },
{ 250+ORG, 125-ORG }
};
 
double angle = 5.0 * M_PI / 180;
double midx1, midy1, midx2, midy2;
 
void rotate (void)
{
int i;
for (i=0; i<5; i++)
{
double xnew, ynew;
 
xnew = midx1 + (face1[i][0] - midx1) * cos (angle) -
(face1[i][1] - midy1) * sin (angle);
ynew = midy1 + (face1[i][0] - midx1) * sin (angle) +
(face1[i][1] - midy1) * cos (angle);
 
face1[i][0] = xnew;
face1[i][1] = ynew;
 
xnew = midx2 + (face2[i][0] - midx2) * cos (angle) -
(face2[i][1] - midy2) * sin (angle);
ynew = midy2 + (face2[i][0] - midx2) * sin (angle) +
(face2[i][1] - midy2) * cos (angle);
 
face2[i][0] = xnew;
face2[i][1] = ynew;
}
 
cleardevice();
 
for (i=0; i<4; i++)
{
setcolor(7);
line (face1[i][0], face1[i][1], face1[i+1][0], face1[i+1][1]);
setcolor(8);
line (face2[i][0], face2[i][1], face2[i+1][0], face2[i+1][1]);
setcolor(9);
line (face1[i][0], face1[i][1], face2[i][0], face2[i][1]);
}
 
delay (125);
}
 
void main()
{
int gd = DETECT, gm;
 
midx1 = (face1[0][0] + face1[1][0]) / 2.0;
midy1 = (face1[1][1] + face1[2][1]) / 2.0;
midx2 = (face2[0][0] + face2[1][0]) / 2.0;
midy2 = (face2[1][1] + face2[2][1]) / 2.0;
 
initgraph (&gd, &gm, "..\\bgi");
 
while (!kbhit())
rotate();
 
closegraph();
}