一个简单的Mac贪吃蛇小游戏开发笔记,设计,算法等等.

前言

最近写了个贪吃蛇小游戏,和各位分享下思路.由于一直做的是iOS方面的工作,所以这次不做iPhone版的了,改做Mac版本.其他无论iPhone还是Mac,代码其实都是基本一致的,只想看iPhone游戏的也可以来看下.

 

游戏设计

蛇的移动由键盘控制,ASDW来改变蛇的移动方向.这是一个最基本的贪吃蛇游戏,实现了蛇的移动,吃食物.

整个程序主要有2个类,SnakeView类和Snake类,还有2个暂时不重要的Food和SnakeBody类.SnakeView是个视图类,主要的功能就是获得蛇和食物的frame,然后画出来,还有就是接受键盘事件,通知Snake类,这个类主要不涉及游戏的逻辑算法.Snake类是游戏的逻辑类,负责蛇的移动,吃食物,设置食物等等,并且告知SnakeView类关于蛇身的位置信息.Food和SnakeBody类主要是保存蛇身和食物的frame,便于绘画,暂时用处不大,如果游戏需要升级的话,Food类需要添加分数,有效时间等属性.

SnakeView类

键盘事件

- (BOOL)acceptsFirstResponder 
{ 
    return YES; 
}

- (void)keyDown: (NSEvent *) event 
{ 
    // the key ADWS for change the direction of the snake
    NSString *chars = [event characters]; 
    
    if ([chars isEqualToString:@"s"]) {
        [self.snake didMoveToDirection:goDown];
    }
    if ([chars isEqualToString:@"w"]) {
        [self.snake didMoveToDirection:goUp];
    }
    if ([chars isEqualToString:@"a"]) {
        [self.snake didMoveToDirection:goLeft];
    }
    if ([chars isEqualToString:@"d"]) {
        [self.snake didMoveToDirection:goRight];
    }
}

在drawRect方法中绘画,获得蛇身和食物的frame,然后使用NSRectFill绘画.

- (void)drawRect:(NSRect)dirtyRect
{
    // set body color of the snake to darkGrayColor
    [[NSColor darkGrayColor] set];

    //get every body of the snake, and draw using NSRectFill
    for (int i = 0; i < [self.snake.bodyArray count]; i++) {
        SnakeBody *body = [self.snake.bodyArray objectAtIndex:i];
        NSRectFill(body.bodyRect);
    }
    
    [[NSColor blackColor] set];
    NSRectFill(self.snake.theFood.foodRect);

}

游戏循环事件,设置一个NSTimer,每0.3秒执行gamePlay方法.

- (void)gamePlay
{
    //move the snake 
    [self.snake move];
    
    //update the game\'s view
    [self setNeedsDisplay:YES];
}

Snake类

一条蛇由N个身体组成,bodyArray变量存储着所以蛇身的位置信息.

移动方法

- (void)move
{
    //根据蛇的前进方向,添加一个新的蛇头,然后删掉一个蛇尾
    //by the move direction of the snake, add a new snake head, and delete the snake tail
    
    //get snake head X&Y
    SnakeBody *headBody = [self.bodyArray objectAtIndex:0];
    CGPoint headPoint = headBody.bodyRect.origin;
    CGPoint p;
    
    //delete the snake tail
    if (!hasEaten) {
        [bodyArray removeLastObject];
    }else{
        hasEaten = NO;
    }
    //add a new snake head
    switch (self.direction) {
        case goUp:
            p = CGPointMake(headPoint.x , headPoint.y - 10);
            break;
        case goDown:
            p = CGPointMake(headPoint.x , headPoint.y + 10);
            break;
        case goLeft:
            p = CGPointMake(headPoint.x - 10, headPoint.y);
            break;
        case goRight:
            p = CGPointMake(headPoint.x + 10, headPoint.y);
            break;
        default:
            break;
    }
    SnakeBody *body = [[SnakeBody alloc] initWithX:p.x andY:p.y];
    [bodyArray insertObject:body atIndex:0];
    [body release];
    
    [self detectSnakeState];
    
}

游戏状态检测

- (void)detectSnakeState
{
    SnakeBody *headBody = [self.bodyArray objectAtIndex:0];
    //touch itself,die   game over
    
    //touch wall,die     game over
    if (headBody.bodyRect.origin.x<0||headBody.bodyRect.origin.x>480||headBody.bodyRect.origin.y<0||headBody.bodyRect.origin.y>360) {
        [self.delegate SnakeDidDie];
    }

    
    //eat food        length+1....       (later,maybe add score and raise speed)
    if (CGRectEqualToRect(headBody.bodyRect,self.theFood.foodRect)) {
        hasEaten = YES;
        [self initTheFood];
    }
}

 

 

 

游戏是开源的,有兴趣的童鞋可以通过这个链接下载:https://github.com/zhungxd/Snake-Game