CubeRotaionAboutCentroid

#include <stdio.h>
#include <graphics.h>
#include <math.h>
#include <stdlib.h>
#include <dos.h>
#include <conio.h>
 
#define ORG -50

double cx=320,cy=320;
double face1[5][2] = {
				{ 320-50, 240-50 },
				{ 320+50, 240-50 },
				{ 320+50, 240+50 },
				{ 320-50, 240+50 },
				{ 320-50, 240-50 }
		           };
 
double face2[5][2] = {
				{ 320-50+ORG, 240-50-ORG },
				{ 320+50+ORG, 240-50-ORG },
				{ 320+50+ORG, 240+50-ORG },
				{ 320-50+ORG, 240+50-ORG },
				{ 320-50+ORG, 240-50-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(9);
	line (face1[i][0], face1[i][1], face1[i+1][0], face1[i+1][1]);
	line (face2[i][0], face2[i][1], face2[i+1][0], face2[i+1][1]);
	line (face1[i][0], face1[i][1], face2[i][0], face2[i][1]);
    }
 
    delay (125);
}
 
int 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, "");
	setbkcolor(WHITE);
    while (!kbhit())
	rotate();
 
    closegraph();
}