/*gr.dc is the persistent layer.  You can access
it directly but two tasks accessing it simultaneously
with no DCAlias() will screw-up color and stuff.
*/

U0 SunMoon()
{
  I64 i,x,y,radius;
  AutoComplete; //AutoComplete Off
  WinBorder;    //No Border
  WinMax;       //Maximize window
  DocClear;     //Clear command-line text
  Fs->text_attr=BLACK<<4+WHITE; //Current CTask is Fs segment register.
  for (i=0; i<0x8000; i+=0x200)
  {
//Sun
    x=0.2*GR_WIDTH;
    y=0.5*GR_HEIGHT;
    radius=120;
    gr.dc->color=DKGRAY;
    GrCircle(gr.dc,x,y,radius);
    gr.dc->color=ROPF_DITHER+RED<<16+YELLOW;
    GrFloodFill(gr.dc,x,y);
    //Moon
    x=0.8*GR_WIDTH-i/0x200;
    y=0.5*GR_HEIGHT;
    radius=75;
    gr.dc->color=DKGRAY;
    GrCircle(gr.dc,x,y,radius);
//<CTRL-ALT-a> for the "pi" character.
    GrCircle(gr.dc,x+0.5*radius,y,1.2*radius,,pi-.31*pi,0.62*pi);
    gr.dc->color=ROPF_PROBABILITY_DITHER+LTGRAY<<16+BLACK;
    gr.dc->dither_probability_u16=i;    //U16 can be [0,65535]
    GrFloodFill(gr.dc,x+0.5*radius,y);
    gr.dc->dither_probability_u16=2*i;  //U16 can be [0,65535]
    GrFloodFill(gr.dc,x-0.75*radius,y);
    Refresh; //Typically 30 fps
    DCFill;
  }
  Fs->text_attr=WHITE<<4+BLUE;
}

SunMoon;