LabWindows/CVI虚拟仪器设计技术场景与游戏设计之： 下雪场景

（2）程序源代码

//头文件声明 
#include "toolbox.h"  
#include "asynctmr.h"  
#include <utility.h>  
#include <ansi_c.h>  
#include "下雪场景.h"  
//全局静态变量 
static int TimerID;  
static int panelHandle;  
static int Snow[1000][3];  
static int PWidth;  
static int PHeight;  
//声明异步定时器 
int CVICALLBACK timer (int reserved, int timerId, int event, void *callbackData, int eventData1, int eventData2);  
//主函数 
int main (int argc, char *argv[])  
{  
int i;  
if (InitCVIRTE (0, argv, 0) == 0)  
return –1;  
if ((panelHandle = LoadPanel (0, " 下雪场景.uir", PANEL)) < 0)  
return –1; 
SetCtrlAttribute (panelHandle, PANEL_CANVAS, ATTR_PEN_COLOR, VAL_WHITE); 
SetCtrlAttribute (panelHandle, PANEL_CANVAS, ATTR_PEN_WIDTH, 1); 
GetPanelAttribute (panelHandle, ATTR_HEIGHT, &PHeight); 
GetPanelAttribute (panelHandle, ATTR_WIDTH, &PWidth); 
//用当前时间产生随机数 
SetRandomSeed (0); 
//随机产生雪花 
for (i = 0; i < 1000; i ++)  
{  
Snow[i][0] = (int) (Random(0, 1) * PWidth);  
Snow[i][1] = (int) (Random(0, 1) * PHeight);  
Snow[i][2] = 10 + (Random(0, 1) * 5);  
}  
//装载异步定时器 
TimerID = NewAsyncTimer (0.2, –1, 1, timer, 0); 
DisplayPanel (panelHandle);  
RunUserInterface ();  
//释放异步定时器资源 
DiscardAsyncTimer (TimerID);  
DiscardPanel (panelHandle);  
return 0; 
}  
//面板回调函数 
int CVICALLBACK PanelCB (int panel, int event, void *callbackData,  
int eventData1, int eventData2)  
{  
switch (event)  
{  
case EVENT_CLOSE:  
// 停止异步定时器 
SuspendAsyncTimerCallbacks (); 
// 延时0.2s  
Delay (0.2);  
QuitUserInterface (0);  
break; 
}  
return 0;  
}  
//异步定时器——绘制下雪场景 
int CVICALLBACK timer (int reserved, int timerId, int event, void *callbackData, int eventData1, int eventData2)  
{  
int i;  
static int OldX;  
static int OldY;  
static int colory;  
static int RGBValue;  
switch (event)  
{  
case EVENT_TIMER_TICK: 
// 禁止弹出运行时错误对话框 
DisableBreakOnLibraryErrors ();  
for (i = 0; i < 1000; i ++)  
{ 
OldX = Snow[i][0];  
OldY = Snow[i][1];  
Snow[i][1] = Snow[i][1] + Snow[i][2];  
if (Snow[i][1] > PHeight) 
{ 
Snow[i][1] = 0;  
Snow[i][2] = 5 + ((double)rand () / RAND_MAX * 50);  
Snow[i][0] = (double)rand () / RAND_MAX * PWidth; 
OldX = 0; 
OldY = 0; 
} 
SetCtrlAttribute (panelHandle, PANEL_CANVAS, ATTR_PEN_COLOR, VAL_BLACK); 
// 绘制雪花点
CanvasDrawPoint (panelHandle, PANEL_CANVAS, MakePoint (OldX, OldY)); 
// 设置雪花灰度渐变色阶 
colory = 8 * (Snow[i][2] -10); 
colory = 60 + colory;  
RGBValue = MakeColor (colory, colory, colory); 
SetCtrlAttribute (panelHandle, PANEL_CANVAS, ATTR_PEN_COLOR, RGBValue);  
CanvasDrawPoint (panelHandle, PANEL_CANVAS, MakePoint (Snow[i][0], Snow[i][1])); 
} 
break; 
}   
return 0;   
}