bitmap.c

source code to compute the visibility polygon of a point in a polygon.

/* Brian O'Connor
 * bitmap.h
 * macros that facilitate treating a 32-bit int as a 32-bit bitmap.
 */

#include "bitmap.h"
#include <assert.h>
#include <stdio.h>

int TestBit(Bitmap b, int i)
{
  assert(i < BITMAP_SIZE);
  return( b & (1 << i) );
}


void SetBit(Bitmap& b, int i)
{
  assert(i < BITMAP_SIZE);
  b = b | (1 << i);
}

void ClearBit(Bitmap& b, int i)
{
  assert(i < BITMAP_SIZE);
  b = b & ( ~(1 << i) );
}


int MapIsClear(Bitmap b)
{
  return( b == 0);
}

void PrintBitmap(Bitmap b)
{
  int i;
  for( i = BITMAP_SIZE - 1; i >= 0; i-- ) {
    if( b & (1 << i) ) {
	printf("1");
    } else printf("0");
  }
  printf("\n");
}

Bitmap ZeroBitmap(void)
{
  return( 0L );
}