#define I_HAVE_REALLY_COOL_OS
#include 
#include 
#include 
#include 
#include 
#include 

long int R = 200, Sq, offset;
int  i,j,x, y, width, height;
bool first_time=true;
long int buff[5];
float z, t;
char c[3];
char color;
FILE* fp;

void draw_damn_thing();


#ifdef I_HAVE_REALLY_COOL_OS
#include 
#include 
GtkWidget * mywnd;
GdkWindowAttr wattr;
GdkGC* my_gc;
GdkColor * cols[16];
void putpixel(int x,int y,char color)
{
  gdk_gc_set_foreground(my_gc,cols[color]);
  gdk_gc_set_fill(my_gc,GDK_SOLID);
  //  gdk_rgb_gc_set_background(my_gc,256*256*color+256*color+color);
  //  gdk_draw_point(mywnd->window,my_gc,x,y);

  /*  switch(color/4)
      {
       case 0:
        my_gc=mywnd->style->white_gc;
        break;
      case 1:
        my_gc=mywnd->style->black_gc;
        break;
      case 3:
        my_gc=*mywnd->style->dark_gc;
        break;
      case 2:
        my_gc=*mywnd->style->light_gc;
        break;
      }*/
  if((x<0)||(y<0)||(x>640)||(y>480))
    printf("(%d,%d)\n",x,y);
  gdk_draw_point(mywnd->window,my_gc,x,y);
  //  if(first_time)
  //    printf("%d ",color);
}
void my_exit()
{
  if(fp!=NULL)
    fclose(fp);
  fp=NULL;
  exit(0);
}
gint gtk_draw_damn_thing(GtkWidget* W)
{
  draw_damn_thing();
  first_time=false;
  return TRUE;
}

GdkColor *NewColor(char color)
{
  GdkColor *c = (GdkColor *) g_malloc (sizeof (GdkColor));

  c->red = 0xffff;
  c->green = 0xffff;
  c->blue = 0xffff;
  gdk_color_alloc(gdk_colormap_get_system(),c);
  c->pixel=color;
  
  return (c);
}


#define delay(x) sleep(x)
#define getch() getchar()
#else
#include                //for exit();
#include                // for delay();
#include  		//for graphics functions
#include                 //for getch()
#include "c:\borlandc\include\graphlib.h"
#endif

void draw_damn_thing()
{
  int vi,vj;
  for( i = 0; i < 640; i++ )
    for( j = 0; j < 480; j++ )
      {
	vi=i-320;
	vj=j-240;
	//	Sq = R*R - (i-320)*(i-320) - (j-240)*(j-240);
	Sq = R*R - vi*vi - vj*vj;
	if( Sq >= 0 )
		{
		  /*			z = sqrt(Sq)-R;       //place map on top of the sphere.
					
					t = 2*R/(2*R+z);
					
					x=(1-t)*320+t*i;
					y=(1-t)*240+t*j;
					//			x = i + t*(320-i) - 320 + width/2;
					//			y = j + t*(240-j) - 240 + height/2;
		  */
		  /*		  z=sqrt(Sq)-R;
				  t=(2*R)/(2*R+z);
				  x=rintf((1-t)*320 + t*i);
				  y=rintf((1-t)*240 + t*j);
		  */

		  z=sqrt(Sq);
		  x=-2*R*vi/(R+z);
		  y=-2*R*vj/(R+z);
		  
		  x+=320;y+=240;
		  //		  x=2*R*(320-i)/(z+2*R)+320;
		  //		  y=2*R*(240-j)/(z+2*R)+240;

		  if(fseek( fp, (y*width + x)/2 + buff[2]+buff[3], SEEK_SET )==-1)
		    printf("x=%d,y=%d,i=%d,j=%d,vi=%d,vj=%d\n",x,y,i,j,vi,vj);
		  fread( &color, sizeof(color), 1, fp );
		  if((y*width + x)%2)
		    color=color&0x0f;
		  else
		    color=(color&0xf0)/16;
		  
		  putpixel(i,j,color);
		  
		} // end if
      } // end for
  // end for
}




int main(int argc,char ** argv)
{

   if(( fp = fopen( "sz22b.bmp", "rb")) == NULL)
   {	printf("Cannot open file\n");
	return 0;
   }

   fread( c, sizeof(char), 2, fp);

   c[2] = '\0';

   fread( &buff[0], sizeof(long int), 1, fp );
   fread( &buff[1], sizeof(long int), 1, fp );
   fread( &buff[2], sizeof(long int), 1, fp );
   fread( &buff[3], sizeof(long int), 1, fp );

   fread( &width, sizeof(long int), 1, fp );
   fread( &height, sizeof(long int), 1, fp );

   cout << "File Type = " << c << endl                      //OK
	<< " Size of file = "  << buff[0] << endl               //ok
	<< " Reserved ( must be 0 ) = " << buff[1] << endl
	<< " Byte offset to bitmap data " << buff[2] << endl
	<< "number of bytes in header = " << buff[3] << endl    //ok
	<< "width = " << width << endl                          //ok
	<< "height = " << height << endl;                       //ok

   cout << "Press a key to continue" << endl << endl;
   getch();


#ifdef I_HAVE_REALLY_COOL_OS
   gtk_init(&argc,&argv);
   gdk_init(&argc,&argv);
   gdk_rgb_init();
   printf("GTK initialized\n");
   mywnd = gtk_window_new ( GTK_WINDOW_TOPLEVEL );
   gtk_signal_connect(GTK_OBJECT(mywnd), "destroy",GTK_SIGNAL_FUNC(my_exit), NULL);
   gtk_widget_set_usize(mywnd,640,480);
   //   gtk_widget_show(mywnd);

   wattr.window_type = GDK_WINDOW_CHILD;
   wattr.wclass = GDK_INPUT_OUTPUT;
   wattr.width = 640;
   wattr.height = 480;
   
   mywnd->window = gdk_window_new(NULL, &wattr, 0);
   gtk_widget_show(mywnd);
   gdk_window_set_title(mywnd->window,"Comp Graphics Homework 11");
   my_gc=gdk_gc_new(mywnd->window);
   gdk_window_show(mywnd->window);
   gtk_timeout_add( 100,gtk_draw_damn_thing, NULL );

   for(i=0;i<16;i++)
     //     {
     cols[i]=NewColor(i);
   //       cols[i]->pixel=i*256+i;
   //     }
   gtk_main();

   sleep(500);
   exit(0);
#else
   int driver = DETECT, mode, errorcode;
   /* initialize graphics and local variables */
   initgraph(&driver, &mode, "c:\\borlandc\\bgi");

   /* read result of initialization */
   errorcode = graphresult();
   if (errorcode != grOk)  /* an error occurred */
     {
       printf("Graphics error: %s\n", grapherrormsg(errorcode));
       printf("Press any key to halt:");
       getch();
       exit(1); /* terminate with an error code */
     }
#endif


   draw_damn_thing();
   getch();

   fclose(fp);

#ifndef I_HAVE_REALLY_COOL_OS
   closegraph();
#endif
   return 0;
}

    Source: geocities.com/siliconvalley/park/1357

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