在SpriteKit中，SKCropNode对SKShapeNode不起作用 [英] In SpriteKit, SKCropNode has no effect over a SKShapeNode

问题描述

我一直在尝试使用SKCropNode将遮罩应用于SKShapeNode，到目前为止没有成功.认为这是SpriteKit错误-这是代码段:

I've been trying to apply a mask to a SKShapeNode using SKCropNode, and so far without success. Thinking that it's a SpriteKit bug - Here is the code snippet:

SKNode* contentNode = [SKNode node];

// picture - use an image bigger than 50x50
SKSpriteNode *pictureNode = [SKSpriteNode spriteNodeWithImageNamed:@"tree"];

// triangle
SKShapeNode* triangleNode = [SKShapeNode node];
UIBezierPath* triangleNodeBezierPath = [[UIBezierPath alloc] init];
[triangleNodeBezierPath moveToPoint:CGPointMake(0.0, 0.0)];
[triangleNodeBezierPath addLineToPoint:CGPointMake(0.0, 100.0)];
[triangleNodeBezierPath addLineToPoint:CGPointMake(50.0, 100.0)];
[triangleNodeBezierPath closePath];

triangleNode.path = triangleNodeBezierPath.CGPath;
triangleNode.fillColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1];

// create a mask
SKSpriteNode *mask = [SKSpriteNode spriteNodeWithColor:[SKColor blackColor] size: CGSizeMake(50, 50)]; //50 by 50 is the size of the mask

// create a SKCropNode
SKCropNode *cropNode = [SKCropNode node];

[cropNode addChild: contentNode];
[cropNode setMaskNode: mask];

[self addChild: cropNode];
[contentNode addChild:pictureNode]; // pictureNode is being cropped
[contentNode addChild:triangleNode]; // triangleNode is not

cropNode.position = CGPointMake( CGRectGetMidX (self.frame), CGRectGetMidY (self.frame));

有人对此问题有解决方法吗?非常感谢！

Does anyone have a workaround about this issue? Thanks a lot!

推荐答案

在一天的大部分时间里，这一直困扰着我.我曾计划创建一个类似于Tony出色的 TCProgressTimer的计时器Chamblee .但是，由于我的应用程序使用多个进度计时器，因此我不需要设计数十种不同大小的Sprite以在不同的分辨率下使用.

This had been bugging me for most of the day. I had planned to create a timer similar to the excellent TCProgressTimer by Tony Chamblee. However, as my application uses multiple progress timers I didn't want to have to design dozens of different sized sprites for use at different resolutions.

我的解决方案是将SKShapeNode对象转换为SKSpriteNode对象.我最终不得不回到基础知识，并使用Core Graphics来完成繁重的工作.我敢肯定，这是一种相当混乱的处理方式，但是我想要快速的结果来动态创建类似于使用SKShapeNode时获得的结果的对象.

My solution was to convert SKShapeNode objects to SKSpriteNode objects. I ended up having to go back to basics and use Core Graphics to do the heavy lifting. This is a rather messy way of doing things, I'm sure, but I wanted quick results to dynamically create objects that would resemble the results obtained when using SKShapeNode.

我目前只对制作圆形对象感兴趣，所以我这样做是这样的:

I am only interested in making circle objects at present, so I did it like this:

-(SKSpriteNode *)createSpriteMatchingSKShapeNodeWithRadius:(float)radius color:(SKColor *)color {
    CALayer *drawingLayer = [CALayer layer];
    CALayer *circleLayer = [CALayer layer];
    circleLayer.frame = CGRectMake(0,0,radius*2.0f,radius*2.0f);
    circleLayer.backgroundColor = color.CGColor;
    circleLayer.cornerRadius = circleLayer.frame.size.width/2.0;
    circleLayer.masksToBounds = YES;


    [drawingLayer addSublayer:circleLayer];

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(circleLayer.frame.size.width, circleLayer.frame.size.height), NO, [UIScreen mainScreen].scale);
    CGContextSetAllowsAntialiasing(UIGraphicsGetCurrentContext(), TRUE);
    CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(), [UIColor clearColor].CGColor);
    CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0,0,circleLayer.frame.size.width,circleLayer.frame.size.height));
    [drawingLayer renderInContext: UIGraphicsGetCurrentContext()];

    UIImage *layerImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithTexture:[SKTexture textureWithImage:layerImage]];


    return sprite;
}

生成的精灵现在可以按预期被SKCropNode遮罩了.由于这些精灵都是在场景开始之前生成的，因此我不会注意到性能受到影响.但是，我想如果您要动态生成多个节点，则此方法效率极低.

The resulting sprite can now be masked by an SKCropNode as expected. As these sprites are all generated before the scene begins, I do not notice a performance hit. However, I would imagine this method is highly inefficient if you are generating multiple nodes on the fly.

我很想听听其他用户的解决方案.希望有帮助.

I would be eager to hear solutions from other users. Hope that helps.

-DC

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