0

我有 22 张图片... 11 张是（rightwall1、rightwall2、rightwall3 等），另外 11 张是（leftwall1、leftwall2、leftwall3 等）

我通过将它们的 y 值设置为之前的墙壁 y 值加上墙壁的高度（所有墙壁的高度相同），将它们放在另一个之上。

这很好用！

现在，我试图使用 arc4random 设置 x 值，以便它们会在一定范围内跳跃整个地方（对于左墙：（-35 到 15）& 对于右墙：（330 到 405））.. .

右边的墙完美地工作，但左边的墙，其中一些工作，但大部分没有出现在屏幕上。

我手动将 x 值 1 设置为 -45，它显示在屏幕上，低于 arc4random 允许的值。

我能想到的唯一问题是我为左墙减去错误？

这是设置墙壁位置的代码，我在整个项目中还没有其他代码。

-(void)awakeFromNib {

        rightWall1.center = CGPointMake( ((arc4random()%75)+330), (460-((rightWall1.frame.size.height)/2)) );//460 = bottom of screen
        rightWall2.center = CGPointMake( ((arc4random()%75)+330), ((rightWall1.center.y)-(rightWall2.frame.size.height)) );
        rightWall3.center = CGPointMake( ((arc4random()%75)+330), ((rightWall2.center.y)-(rightWall3.frame.size.height)) );
        rightWall4.center = CGPointMake( ((arc4random()%75)+330), ((rightWall3.center.y)-(rightWall4.frame.size.height)) );
        rightWall5.center = CGPointMake( ((arc4random()%75)+330), ((rightWall4.center.y)-(rightWall5.frame.size.height)) );
        rightWall6.center = CGPointMake( ((arc4random()%75)+330), ((rightWall5.center.y)-(rightWall6.frame.size.height)) );
        rightWall7.center = CGPointMake( ((arc4random()%75)+330), ((rightWall6.center.y)-(rightWall7.frame.size.height)) );
        rightWall8.center = CGPointMake( ((arc4random()%75)+330), ((rightWall7.center.y)-(rightWall8.frame.size.height)) );
        rightWall9.center = CGPointMake( ((arc4random()%75)+330), ((rightWall8.center.y)-(rightWall9.frame.size.height)) );
        rightWall10.center = CGPointMake( ((arc4random()%75)+330), ((rightWall9.center.y)-(rightWall10.frame.size.height)) );
        rightWall11.center = CGPointMake( ((arc4random()%75)+330), ((rightWall10.center.y)-(rightWall11.frame.size.height)) );


        leftWall1.center = CGPointMake( (15-(arc4random()%50)), (460-((leftWall1.frame.size.height)/2)) );
        leftWall2.center = CGPointMake( (15-(arc4random()%50)), ((leftWall1.center.y)-(leftWall2.frame.size.height)) );
        leftWall3.center = CGPointMake( (15-(arc4random()%50)), ((leftWall2.center.y)-(leftWall3.frame.size.height)) );
        leftWall4.center = CGPointMake( (15-(arc4random()%50)), ((leftWall3.center.y)-(leftWall4.frame.size.height)) );
        leftWall5.center = CGPointMake( (15-(arc4random()%50)), ((leftWall4.center.y)-(leftWall5.frame.size.height)) );
        leftWall6.center = CGPointMake( (15-(arc4random()%50)), ((leftWall5.center.y)-(leftWall6.frame.size.height)) );
        leftWall7.center = CGPointMake( (15-(arc4random()%50)), ((leftWall6.center.y)-(leftWall7.frame.size.height)) );
        leftWall8.center = CGPointMake( (15-(arc4random()%50)), ((leftWall7.center.y)-(leftWall8.frame.size.height)) );
        leftWall9.center = CGPointMake( (15-(arc4random()%50)), ((leftWall8.center.y)-(leftWall9.frame.size.height)) );
        leftWall10.center = CGPointMake( (15-(arc4random()%50)), ((leftWall9.center.y)-(leftWall10.frame.size.height)) );
        leftWall11.center = CGPointMake( (15-(arc4random()%50)), ((leftWall10.center.y)-(leftWall11.frame.size.height)) );

}
4

1 回答 1

0

原来你不能使用 arc4random 获得负整数值（因为 arc4random 使用模数......整数......？？哈哈）所以我使用浮点数......

不能说：

(-1)*(arc4random() ....

你不得不说：

float num1;
num1 = -1;
(num1)*(arc4random() ....

奇怪......减法也是如此......你必须添加负1浮点乘以arc4random ..

于 2011-05-31T04:49:39.127 回答