objective-c – 如何在iOS中切片/切割精灵(核心图形)

我正在开发一款游戏,我想在其中添加一个合适的切片功能..所以当精灵切片时,应该创建2个新的精灵..请检查 here

目前,我只是缩小尺寸并复制精灵..这样的东西..在此先感谢..

- (BOOL) sliceSprite: (Sprite *) sprite withPath: (UIBezierPath *) slicePath


 {

            CGSize size = sprite.size;
            size.width /= 2; 
            size.height /=2;
            sprite.size = size;
            sprite.sliced = YES;

            Sprite *newSprite = [[Sprite alloc] initWithImage: sprite.image];

            newSprite.position = sprite.position;
            newSprite.size = size;
            newSprite.sliced = YES;
            newSprite.inView = YES;
            newSprite.xVelocity = SLICE_SPEEDUP * sprite.yVelocity;
            newSprite.yVelocity = SLICE_SPEEDUP * sprite.xVelocity;
            newSprite.angularVelocity = -SLICE_REVUP * sprite.angularVelocity;

            [sprites addObject: newSprite];
            [newSprite release];

        sprite.angularVelocity = SLICE_REVUP * sprite.angularVelocity;
            sprite.xVelocity = -SLICE_SPEEDUP * sprite.xVelocity;
            sprite.yVelocity = -SLICE_SPEEDUP * sprite.yVelocity;

            return YES;
    }

- (void) sliceSpritesInSwipePath
{
    CGRect swipeRect = [swipePath bounds];


        for (NSUInteger i = 0; i < [sprites count]; i++)
        {
                Sprite *sprite = [sprites objectAtIndex: i];

                if ([sprite intersectsWithPathInArray: swipePoints
                                               inRect: swipeRect])
                        if ([self sliceSprite: sprite withPath: swipePath])
                        {

                                [self resetSwipe];

                                if (![sliceSound isPlaying])
                                        [sliceSound play];

                break;
                        }
        }

}

解决方法

既然你在这里使用CoreGraphics,为什么不在绘制精灵时简单地使用剪切路径呢？

复制要切片的精灵,然后应用将两半遮盖的简单多边形作为各自的剪切路径.您需要的功能称为CGContextClip,可以找到简短的教程here.

编辑：教程列出了这个例子：

CGContextBeginPath (context);
CGContextAddArc (context,w/2,h/2,((w>h) ? h : w)/2,2*PI,0);
CGContextClosePath (context);
CGContextClip (context);

这会将当前路径设置为圆,然后将当前路径应用为剪切区域.