Drawing lines with Bresenham's Line Algorithm

Question

My computer graphics homework is to implement OpenGL algorithms using only the ability to draw points.

So obviously I need to get drawLine() to work bef

Answer 1

You can find the complete code in C++ to draw a line using Bresenham Algorithm at http://www.etechplanet.com/codesnippets/computer-graphics-draw-a-line-using-bresenham-algorithm.aspx:

/*BRESENHAAM ALGORITHM FOR LINE DRAWING*/
#include
#include
#include
#include
#include
#include
#include
void bhm_line(int,int,int,int,int);
void main()
{
 int ghdriver=DETECT,ghmode,errorcode,x1,x2,y1,y2;
 initgraph(&ghdriver,&ghmode,"..\\bgi");
 errorcode = graphresult();
 if(errorcode !=grOk)
 {
  cout<<"Graphics error:%s\n"<>x1>>y1;
 cout<<"Enter the coordinates (x2,y2): ";
 cin>>x2>>y2;
 bhm_line(x1,y1,x2,y2,1);
 getch();
}
void bhm_line(int x1,int y1,int x2,int y2,int c)
{
 int x,y,dx,dy,dx1,dy1,px,py,xe,ye,i;
 dx=x2-x1;
 dy=y2-y1;
 dx1=fabs(dx);
 dy1=fabs(dy);
 px=2*dy1-dx1;
 py=2*dx1-dy1;
 if(dy1<=dx1)
 {
  if(dx>=0)
  {
   x=x1;
   y=y1;
   xe=x2;
  }
  else
  {
   x=x2;
   y=y2;
   xe=x1;
  }
  putpixel(x,y,c);
  for(i=0;x0 && dy>0))
    {
     y=y+1;
    }
    else
    {
     y=y-1;
    }
    px=px+2*(dy1-dx1);
   }
   delay(0);
   putpixel(x,y,c);
  }
 }
 else
 {
  if(dy>=0)
  {
   x=x1;
   y=y1;
   ye=y2;
  }
  else
  {
   x=x2;
   y=y2;
   ye=y1;
  }
  putpixel(x,y,c);
  for(i=0;y0 && dy>0))
    {
     x=x+1;
    }
    else
    {
     x=x-1;
    }
    py=py+2*(dx1-dy1);
   }
   delay(0);
   putpixel(x,y,c);
  }
 }
}