#include "wgtgfx.h"
#include <time.h>


void shadedline (int x1, int firstcolor, int x2, int lastcolor, int y)
{
int length;
int numcolors;
int colorvalue;
int step;
int x;
unsigned char far * dest;   /* Ptr to the screen */

 length = x2 - x1 + 1;
 if (length > 0)
 {
  numcolors = lastcolor - firstcolor + 1;

  colorvalue = firstcolor << 8;
  step = ((long)numcolors << 8) / (long)length;

  dest = abuf + y * 320 + x1;
  /* Make a pointer to the first pixel */


  /* Begin assembly optimization */
  if (length > 0)
   {
    asm {
	mov cx, word ptr length		/* Set length */
	les di, dest			/* Set destination ptr */
	mov ax, word ptr colorvalue	/* Set color */
       }
    shadedlineloop:
    ;
    asm {
	mov es:di, ah			/* Move color to screen */
	add ax, word ptr step  		/* Add to color */
	inc di				/* Move to next pixel */
	dec cx				/* Decrease length */
	jnz shadedlineloop		/* Repeat for all pixels */
	}
   }
 }
}


void main (void)
{
int i;
unsigned char col;

 setvga256 ();

 do {
 col = rand () % 256;  /* Pick a random color for the right endpoint */
		       /* This will let us see how fast the screen is
			  being updated. You may want to take the turbo
			  button off for a while to see what speed it
			  runs at. */
 for (i = 0; i < 200; i++)
    shadedline (0, 0, 319 - i, col, i);

 } while (!kbhit ());

 getch ();
 setvideomode (3);

}