#include "graphics.h"
#include "math.h"
#define X 0
#define Y 1
#define Z 2
typedef float point[3];
int x=0,y=0;
void display(point * P,int n,int color)
{
float C[3][4],t,deltat;
  point point1,point2;
  int i,j;
  setcolor(color);
  for(j=0;j<3;j++)
 {  C[j][0]=P[0][j];
    C[j][1]=-3*P[0][j]+3*P[1][j];
    C[j][2]=3*P[0][j]-6*P[1][j]+3*P[2][j];
    C[j][3]=-P[0][j]+3*P[1][j]-3*P[2][j]+P[3][j];
     /*C[j][0]=P[0][j]-3*P[1][j]+3*P[2][j]-P[3][j];
    C[j][1]=-3*P[1][j]-6*P[2][j]+3*P[3][j];
    C[j][2]=3*P[2][j]-3*P[3][j];
    C[j][3]=P[3][j]; */
 }
  point1[X]=P[0][X];point1[Y]=P[0][Y];point1[Z]=P[0][Z];
  deltat=1.0/n;
  t=0.0;
  for(i=1;i<=n;i++)
  { t+=deltat;
    point2[X]=C[X][0]+t*(C[X][1]+t*(C[X][2]+t*C[X][3]));
    point2[Y]=C[Y][0]+t*(C[Y][1]+t*(C[Y][2]+t*C[Y][3]));
    point2[Z]=C[Z][0]+t*(C[Z][1]+t*(C[Z][2]+t*C[Z][3]));
    line(point1[0],point1[1], point2[0],point2[1]);
    point1[X]=point2[X];point1[Y]=point2[Y]; point1[Z]=point2[Z];
  }
}
void zhongxing(int x,int y,int s)
{ int i;
   for(i=x-5;i<=x+5;i++)
    {   putpixel(i,y,s);}
    for(i=y-5;i<=y+5;i++)
    {   putpixel(x,i,s);
       }
}

void kongdian(point * pot,int color)
{ int i;
  setcolor(color);
 for(i=0;i<4;i++)
 {  circle(pot[i][X],pot[i][Y],3);   }

}

void shuchu(char * s,int color)
{    setcolor(color);
     outtextxy(0,0,s);
}
void main()

{int driver=DETECT,mode; int i=0,j,key,s=1;
point pot[4]={{100,200,0},{200,250,0},{300,200,0},{400,250,0}};
 char s1[]="PLEASE CHOOSE THE CONTROL POINT",s2[]="PLEASE MOVE THE CONTROL POINT",s3[]="ESC BE PRESSED";
 registerbgidriver(EGAVGA_driver);
 initgraph(&driver,&mode,"\\tc");
shuchu(s1,14);
kongdian(pot,5);
display(pot,50,4);
zhongxing(pot[i][X],pot[i][Y],2);
for(;;)
 { if(bioskey(1))

   { key=bioskey(0);
     if(key==0x4d00)
       { if(s==1)
        { if(i!=3)
         {zhongxing(pot[i][X],pot[i][Y],0);
         i+=1;
         zhongxing(pot[i][X],pot[i][Y],2);
         }
        }
        if(s==-1)
         { display(pot,50,0);kongdian(pot,0);zhongxing(pot[i][X],pot[i][Y],0);
           pot[i][X]+=1;
           display(pot,50,4);kongdian(pot,5);zhongxing(pot[i][X],pot[i][Y],2);
         }

     }


   if(key==0x011b)
   { outtextxy(0,20,s3);

   break;
   }

  if(key==0x4b00)
   {
      if(s==1)
      {if(i!=0)
        {zhongxing(pot[i][X],pot[i][Y],0);
        i-=1;
        zhongxing(pot[i][X],pot[i][Y],2);}
       }
       if(s==-1)
         {display(pot,50,0);kongdian(pot,0);zhongxing(pot[i][X],pot[i][Y],0);
           pot[i][X]-=1;
           display(pot,50,4);kongdian(pot,5);zhongxing(pot[i][X],pot[i][Y],2);
         }



   }
   if(key==0x5000)
      {
       if(s==-1)
         {display(pot,50,0);kongdian(pot,0);zhongxing(pot[i][X],pot[i][Y],0);
           pot[i][Y]+=1;
           display(pot,50,4);kongdian(pot,5);zhongxing(pot[i][X],pot[i][Y],2);
         }
       }
    if(key==0x4800)
      {
        if(s==-1)
         {display(pot,50,0);kongdian(pot,0);zhongxing(pot[i][X],pot[i][Y],0);
           pot[i][Y]-=1;
           display(pot,50,4);kongdian(pot,5);zhongxing(pot[i][X],pot[i][Y],2);
         }
        }/**/
     if(key==0x1c0d)
     { if(s==1) { shuchu(s1,0);shuchu(s2,14); }
       else {  shuchu(s2,0);shuchu(s1,14);  }
       s=-s;
     }


 }
 }
getch();

closegraph();
}