如何通过SKEffectNode在精灵周围创建一个辉光-HowcanyoucreateaglowaroundaspriteviaSKEffectNode

27  

@rickster's answer is great. Since I have low rep, I'm apparently not allowed to add this code as a comment to his. I hope this doesn't break stackoverflow rules of propriety. I'm not trying to userp his rep in any way.

@rickster的回答是伟大的。由于我有一个低代表，我显然不允许添加这段代码作为他的评论。我希望这不会违反stackoverflow的礼节规则。我不会试图以任何方式利用他的代表。

Here's code that does what he's describing in his answer:

这是他在回答中所描述的代码

Header:

标题:

//  ENHGlowFilter.h
#import 

@interface ENHGlowFilter : CIFilter

@property (strong, nonatomic) UIColor *glowColor;
@property (strong, nonatomic) CIImage *inputImage;
@property (strong, nonatomic) NSNumber *inputRadius;
@property (strong, nonatomic) CIVector *inputCenter;

@end

//Based on ASCGLowFilter from Apple

Implementation:

实现:

#import "ENHGlowFilter.h"

@implementation ENHGlowFilter

-(id)init
{
    self = [super init];
    if (self)
    {
        _glowColor = [UIColor whiteColor];
    }
    return self;
}

- (NSArray *)attributeKeys {
    return @[@"inputRadius", @"inputCenter"];
}

- (CIImage *)outputImage {
    CIImage *inputImage = [self valueForKey:@"inputImage"];
    if (!inputImage)
        return nil;

    // Monochrome
    CIFilter *mOnochromeFilter= [CIFilter filterWithName:@"CIColorMatrix"];
    CGFloat red = 0.0;
    CGFloat green = 0.0;
    CGFloat blue = 0.0;
    CGFloat alpha = 0.0;
    [self.glowColor getRed:&red green:&green blue:&blue alpha:&alpha];
    [monochromeFilter setDefaults];
    [monochromeFilter setValue:[CIVector vectorWithX:0 Y:0 Z:0 W:red] forKey:@"inputRVector"];
    [monochromeFilter setValue:[CIVector vectorWithX:0 Y:0 Z:0 W:green] forKey:@"inputGVector"];
    [monochromeFilter setValue:[CIVector vectorWithX:0 Y:0 Z:0 W:blue] forKey:@"inputBVector"];
    [monochromeFilter setValue:[CIVector vectorWithX:0 Y:0 Z:0 W:alpha] forKey:@"inputAVector"];
    [monochromeFilter setValue:inputImage forKey:@"inputImage"];
    CIImage *glowImage = [monochromeFilter valueForKey:@"outputImage"];

    // Scale
    float centerX = [self.inputCenter X];
    float centerY = [self.inputCenter Y];
    if (centerX > 0) {
        CGAffineTransform transform = CGAffineTransformIdentity;
        transform = CGAffineTransformTranslate(transform, centerX, centerY);
        transform = CGAffineTransformScale(transform, 1.2, 1.2);
        transform = CGAffineTransformTranslate(transform, -centerX, -centerY);

        CIFilter *affineTransformFilter = [CIFilter filterWithName:@"CIAffineTransform"];
        [affineTransformFilter setDefaults];
        [affineTransformFilter setValue:[NSValue valueWithCGAffineTransform:transform] forKey:@"inputTransform"];
        [affineTransformFilter setValue:glowImage forKey:@"inputImage"];
        glowImage = [affineTransformFilter valueForKey:@"outputImage"];
    }

    // Blur
    CIFilter *gaussianBlurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
    [gaussianBlurFilter setDefaults];
    [gaussianBlurFilter setValue:glowImage forKey:@"inputImage"];
    [gaussianBlurFilter setValue:self.inputRadius ?: @10.0 forKey:@"inputRadius"];
    glowImage = [gaussianBlurFilter valueForKey:@"outputImage"];

    // Blend
    CIFilter *blendFilter = [CIFilter filterWithName:@"CISourceOverCompositing"];
    [blendFilter setDefaults];
    [blendFilter setValue:glowImage forKey:@"inputBackgroundImage"];
    [blendFilter setValue:inputImage forKey:@"inputImage"];
    glowImage = [blendFilter valueForKey:@"outputImage"];

    return glowImage;
}


@end

In use:

在使用:

@implementation ENHMyScene //SKScene subclass

-(id)initWithSize:(CGSize)size {    
    if (self = [super initWithSize:size]) {
        /* Setup your scene here */
        [self setAnchorPoint:(CGPoint){0.5, 0.5}];
        self.backgroundColor = [SKColor colorWithRed:0.15 green:0.15 blue:0.3 alpha:1.0];

        SKEffectNode *effectNode = [[SKEffectNode alloc] init];
        ENHGlowFilter *glowFilter = [[ENHGlowFilter alloc] init];
        [glowFilter setGlowColor:[[UIColor redColor] colorWithAlphaComponent:0.5]];
        [effectNode setShouldRasterize:YES];
        [effectNode setFilter:glowFilter];
        [self addChild:effectNode];
        _effectNode = effectNode;
    }
    return self;
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    /* Called when a touch begins */

    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInNode:self];
        SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite.position = location;
        [self.effectNode addChild:sprite];
    }
}

22  

You can create a glow effect in Core Image by creating a CIFilter subclass that composes multiple built-in filters. Such a filter would involve steps like these:

通过创建一个包含多个内置过滤器的CIFilter子类，您可以在核心映像中创建一个辉光效果。这样的过滤器将包括以下步骤:

1. Create an image to be used as the blue glow. There's probably a few decent ways to do this; one is to use CIColorMatrix to create a monochrome version of the input image.
2. 创建一个用作蓝色辉光的图像。可能有一些不错的方法;一种是使用CIColorMatrix创建输入图像的单色版本。
3. Scale up and blur the glow image (CIAffineTransform + CIGaussianBlur).
4. 放大和模糊辉光图像(CIAffineTransform + CIGaussianBlur)。
5. Composite the original input image over the glow image (CISourceOverCompositing).
6. 在辉光图像上组合原始输入图像(CISourceOverCompositing)。

Once you have a CIFilter subclass that does all that, you can use it with a SKEffectNode to get a realtime glow around the effect node's children. Here it is running in the "Sprite Kit Game" Xcode template on an iPad 4:

一旦您有了一个CIFilter子类来完成所有这些工作，您就可以将它与一个SKEffectNode一起使用，从而在effect节点的子节点周围获得实时的辉光。它在ipad4的“Sprite Kit Game”Xcode模板中运行:

I got this up and running in a few minutes by cribbing the custom filter class used for a similar effect in the Scene Kit presentation from WWDC 2013 -- grab it from the WWDC Sample Code package at developer.apple.com/downloads, and look for the ASCGlowFilter class. (If you want to use that code on iOS, you'll need to change the NSAffineTransform part to use CGAffineTransform instead. I also replaced the centerX and centerY properties with an inputCenter parameter of type CIVector so Sprite Kit can automatically center the effect on the sprite.)

我在WWDC 2013年的场景工具包演示中使用了定制过滤器类，并在几分钟内运行了它——从developer.apple.com/downloads的WWDC示例代码包中获取它，然后查找ASCGlowFilter类。(如果您想在iOS中使用该代码，则需要更改NSAffineTransform部分以使用CGAffineTransform。我还用CIVector类型的inputCenter参数替换了centerX和centerY属性，这样Sprite Kit就可以自动将效果居中。)

Did I say "realtime" glow? Yup! That's short for "really eats CPU time". Notice in the screenshot it's no longer pegged at 60 fps, even with only one spaceship -- and with the software OpenGL ES renderer on the iOS Simulator, it runs at slideshow speed. If you're on the Mac, you probably have silicon to spare... but if you want to do this in your game, keep some things in mind:

我说过"实时"辉光吗?是的!这是“真的吃了CPU时间”的缩写。请注意，在截图中，即使只有一艘宇宙飞船，它也不再以60帧每秒的速度被锁定——而iOS模拟器上的OpenGL ES渲染器软件，它的运行速度也是以幻灯片的速度。如果你在Mac电脑上，你可能有多余的硅……但如果你想在游戏中做到这一点，记住以下几点:

• There are probably some ways to get better performance out of the filter itself. Play with different CI filters and you might see some improvement (there are several blur filters in Core Image, some of which will certainly be faster than Gaussian). Also note blur effects tend to be fragment-shader bound, so the smaller the image and the smaller the glow radius the better.
• 可能有一些方法可以从过滤器本身获得更好的性能。使用不同的CI过滤器，您可能会看到一些改进(Core Image中有几个模糊过滤器，其中一些肯定比高斯的要快)。另外，注意模糊效果往往是碎片着色的边界，所以图像越小，辉光半径越小越好。
• If you want to have multiple glows in a scene, consider making all the glowing sprites children of the same effect node -- that'll render them all into one image, then apply the filter once.
• 如果你想在一个场景中有多个发光点，可以考虑把所有发光的精灵都放在同一个效果节点上——这样可以把它们全部渲染成一个图像，然后再应用一次滤镜。
• If the sprites to be glowed don't change much (e.g. if our spaceship wasn't rotating), setting shouldRasterize to YES on the effect node should help a lot. (Actually, in this case, you might get some improvement by rotating the effect node instead of the sprite within it.)
• 如果要发光的精灵变化不大(例如，如果我们的飞船没有旋转)，那么在效果节点上设置shouldRasterize为YES应该会有很大的帮助(实际上，在这种情况下，您可以通过旋转效果节点而不是其中的精灵来获得一些改进)。
• Do you really need realtime glow? As with many spiffy graphical effects in games, you'll get much better performance if you fake it. Make a blurry, bluey spaceship in your favorite graphics editor and put it in the scene as another sprite.
• 你真的需要实时发光吗?就像游戏中许多华丽的图形效果一样，如果你假装它，你会得到更好的性能。在你最喜欢的图形编辑器中做一个模糊的，蓝色的宇宙飞船，把它作为另一个精灵。

3  

You could use a SKShapeNode behind the sprite and define a glow using it's glowWidth and strokeColor properties. If you size and position it right, this should give you the appearance of a glow. This doesn't give you many options for customization, but I imagine it's much easier than using a CIFilter with an SKEffectNode which is likely the other logical option you have for this.

您可以使用精灵后面的SKShapeNode并使用它的glowWidth和strokeColor属性定义辉光。如果你的尺寸和位置正确，这应该会让你看起来容光焕发。这并没有为您提供许多定制选项，但我认为这比使用带有SKEffectNode的CIFilter要容易得多，后者很可能是您拥有的另一个逻辑选项。