一个让屏幕飘雪的程序 源代码...c语言写成

#include <windows.h>
#include <time.h>
const int ScrnWidth=1366;
const int ScrnHight=768;
const long SnowCol =0xFEFFFE;
const long SnowColDown=0xFFFFFF;
const long SnowColDuck =0xFFDDDD;
const int SnowNum = 500;
const int ID_TIMER = 1;

const char g_szClassName[]="my WindowsClass";
typedef struct POINTAPI
{long x;
 long y;
}a;
static HDC hDC1;
static struct POINTAPI pData[500];
static long pColor[500];
static int Vx,Vy,PVx,PVy,timecont;

long Abs(long num)
{ if(num>=0)  return(num);
else return(-num);
}

int Random (int max)
{return (rand()%max);
}
 
 int InitP(int i)

 {pData[i].x=Random(ScrnWidth);
  pData[i].y=Random(5);
  pColor[i]=GetPixel(hDC1,pData[i].x,pData[i].y);
  return 0;
 }
 
 long GetContrast(int i)
 {long ColorCmp;
  long tempR;
  long tempG;
  long tempB;
  int Slope;
  if(PVy!=0)  Slope = PVx / PVy;
  else Slope=2;
 if(Slope==0)ColorCmp = GetPixel(hDC1,pData[i].x,pData[i].y+1);
 else if(Slope>1) ColorCmp =GetPixel(hDC1,pData[i].x+1,pData[i].y+1);
 if(ColorCmp==SnowCol) return 0;
 tempB =Abs((ColorCmp>>16)&0xff-(pColor[i]>>16)&0xff);
 tempG=Abs((ColorCmp>>8)&0xff-(pColor[i]>>8)&0xff);
 tempR=Abs((ColorCmp)&0xff-(pColor[i])&0xff);
 (tempR*0.114+tempG*0.587+tempB*0.299);
 return ((tempR+tempG+tempB)/3);
 }
 
 void DrawP(void)
 {   int i;
  for(i=0;i<SnowNum;i++)
  {if(pColor[i]!=SnowCol&&pColor[i]!=-1)SetPixel(hDC1,pData[i].x,pData[i].y,pColor[i]);
  PVx = Random(2)-1+Vx*(i%3);
  PVy = Vy*(i%3+1);