/****************************************************************************
** 貪吃蛇程序說明：
**
** 上下左右控制方向，esc重新開始，P鍵暫停游戲
** 
** 游戲5個關卡，gamespeed為游戲速度，吃10個方塊進入下關，游戲暫停，按P鍵繼續(xù)
**
** QT3的代碼，供大家交流！
**
**                              --by snailshell   mail：youngst@yeah.net
****************************************************************************/


#include <qapplication.h>
#include <qpalette.h>
#include "snake.h"
#define N 100
#define LEFT 0x1012
#define RIGHT 0x1014
#define DOWN 0x1015
#define UP 0x1013
#define ESC 0x1000
#define PAUSE 0X50
struct Food{  
    int x;/*食物的橫坐標*/  
    int y;/*食物的縱坐標*/   
    int yes;/*判斷是否要出現(xiàn)食物的變量*/
   }food;
/*食物的結構體*/

struct Snake{  
    int x[N];   
	int y[N];  
	int node;/*蛇的節(jié)數(shù)*/  
	int direction;/*蛇移動方向*/   
	int life;/* 蛇的生命,0活著,1死亡*/
	}snake;
SnakeGame::SnakeGame(QWidget *parent,const char *name,WFlags f):QWidget(parent,name,f)
{
	
SnakeTime=new QTimer(this);
QObject::connect(SnakeTime,SIGNAL(timeout()),this,SLOT(SnakeRun()));
lcd =new QLCDNumber(5,this,"");

lcd->setSegmentStyle( QLCDNumber::Flat );
lcd->setFrameStyle( QFrame::NoFrame | QFrame::Plain );

InitGame();

}
void SnakeGame::paintEvent(QPaintEvent *event)
{
	
	QPainter paint( this );

    QRect v = paint.viewport();
    
    paint.setViewport( v.left() ,
			v.top() , width(), height());

	lcd->setGeometry(width()-100,5,100,30);
     DrawGame(&paint);
     PlayGame(&paint);
 
    


}
void SnakeGame::InitGame()
{
	

	pause=1;stage=1,score=0;gamespeed =400;key=0;
	setPaletteBackgroundColor(QColor(192,253,123)); 
	
SnakeTime->start(gamespeed,false);

food.yes=1;/*1表示需要出現(xiàn)新食物,0表示已經(jīng)存在食物*/
   snake.life=0;/*活著*/
   snake.direction=1;/*方向往右*/
   snake.x[0]=50;snake.y[0]=100;/*蛇頭*/
   snake.x[1]=40;snake.y[1]=100;
   snake.node=2;/*節(jié)數(shù)*/
   }

void SnakeGame::SnakeRun()
{

update();

}

void SnakeGame::GameScore()
{
	
	lcd->display(score);
	
	
}
void SnakeGame::DrawGame(QPainter *painter)
{

painter->setPen( QPen(QColor( 41,75,35),1,Qt::SolidLine,Qt::RoundCap,Qt::RoundJoin)); 

for(i=0;i<=18;i+=2)/*畫圍墻*/
   {
     painter->drawRect(i,i+40,width()-2*i,height()-2*i-40); 
     
   }
 

}
void SnakeGame::PlayGame(QPainter *painter)
{
  

  GameScore();/*輸出得分*/
  
  if(food.yes==1)/*需要出現(xiàn)新食物*/
  {
      food.x=rand()%width()/2+20;
      food.y=rand()%height()/2+20+40;
      while(food.x%10!=0)/*食物隨機出現(xiàn)后必須讓食物能夠在整格內,這樣才可以讓蛇吃到*/
  food.x++;
      while(food.y%10!=0)
  food.y++;
  food.yes=0;/*畫面上有食物了*/
  }
  if(food.yes==0)/*畫面上有食物了就要顯示*/
  {painter->setBrush( QColor(Qt::yellow ));
            
            painter->drawRoundRect(food.x,food.y,10,10,50,50);
  }
  if(snake.life==0&&pause==1)/*蛇移動*/
	  {
QString str;
str = QString( "GAME STAGE : %1" )
          .arg( stage);
painter->drawText(10,20,str);
 for(i=snake.node-1;i>0;i--)/*蛇的每個環(huán)節(jié)往前移動,也就是貪吃蛇的關鍵算法*/
         {
            snake.x[i]=snake.x[i-1];
     snake.y[i]=snake.y[i-1];
  }
    /*1,2,3,4表示右,左,上,下四個方向,通過這個判斷來移動蛇頭*/
		if(key==UP&&snake.direction!=4)
/*判斷是否往相反的方向移動*/
   snake.direction=3;
       else
   if(key==RIGHT&&snake.direction!=2)
      snake.direction=1;
   else
      if(key==LEFT&&snake.direction!=1)
  snake.direction=2;
      else
  if(key==DOWN&&snake.direction!=3)
     snake.direction=4;
 
         switch(snake.direction)
  {
     case 1: snake.x[0]+=10;break;
     case 2: snake.x[0]-=10;break;
     case 3: snake.y[0]-=10;break;
     case 4: snake.y[0]+=10;break;
  }

  
  for(i=3;i<snake.node;i++)/*從蛇的第四節(jié)開始判斷是否撞到自己了，因為蛇頭為兩節(jié)，第三節(jié)不可能拐過來*/
  {
     if(snake.x[i]==snake.x[0]&&snake.y[i]==snake.y[0])
     {
               snake.life=1;
               break;
     }
        }
if(snake.x[0]<30||snake.x[0]>width()-40||snake.y[0]<70||
    snake.y[0]>height()-40)/*蛇是否撞到墻壁*/
{
  
     snake.life=1; /*蛇死*/

}   
if(snake.x[0]==food.x&&snake.y[0]==food.y)/*吃到食物以后*/
{
        painter->setBrush( QColor( 192,253,123));
        painter->drawRoundRect(food.x,food.y,10,10,50,50); /*把畫面上的食物東西去掉*/
    snake.x[snake.node]=-20;snake.y[snake.node]=-20;
          /*新的一節(jié)先放在看不見的位置,下次循環(huán)就取前一節(jié)的位置*/
    snake.node++;/*蛇的身體長一節(jié)*/
    food.yes=1;/*畫面上需要出現(xiàn)新的食物*/
    score+=10;
	
    GameScore();/*輸出新得分*/

	if(snake.node>10*stage+1&&stage<6)
		{
		stage+=1;
		gamespeed=gamespeed-100;
		pause=0;
		}/*關卡速度變快，游戲暫停*/

}
	
}
else	
{
	SnakeTime->stop();	

	if(pause==1)painter->drawText(10,20,"GAME  OVER!");
	else painter->drawText(10,20,"GAME  PAUSE!");
	
}/*游戲結束、暫停*/
painter->setBrush( QColor( Qt::red));painter->drawRoundRect(snake.x[0],snake.y[0],10,
               10,50,50);painter->setBrush( QColor( Qt::blue));
for(i=1;i<snake.node;i++)
     painter->drawRoundRect(snake.x[i],snake.y[i],10,
               10,50,50);/*畫出蛇*/

 painter->setPen( QPen(QColor( QColor(192,253,123)),1,Qt::SolidLine,Qt::RoundCap,Qt::RoundJoin));painter->setBrush( QColor( 192,253,123));
 painter->drawRoundRect(snake.x[snake.node-1],snake.y[snake.node-1],
10,10,50,50);/*去除蛇的的最后一節(jié)*/
 
    

}

void SnakeGame::keyPressEvent(QKeyEvent *k)
{
key= k->key();
if(key==ESC){SnakeTime->stop();InitGame();}
if(key==PAUSE)
	{
       if(SnakeTime->isActive())
		{//SnakeTime->stop();
	   pause=0;}
	   else
		   {
		   SnakeTime->start(gamespeed,false);
		   pause=1;
           }
	 }
}