How to Create a Glow Around a Sprite via Skeffectnode

How can you create a glow around a sprite via SKEffectNode

@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.

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

Header:

//  ENHGlowFilter.h
#import <CoreImage/CoreImage.h>

@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:

#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:

@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];
}
}

Add glowing effect to an SKSpriteNode

I created this extension to add a glow effect to an SKSpriteNode

Just add this to your project

extension SKSpriteNode {

func addGlow(radius: Float = 30) {
let effectNode = SKEffectNode()
effectNode.shouldRasterize = true
addChild(effectNode)
let effect = SKSpriteNode(texture: texture)
effect.color = self.color
effect.colorBlendFactor = 1
effectNode.addChild(effect)
effectNode.filter = CIFilter(name: "CIGaussianBlur", parameters: ["inputRadius":radius])
}
}

Now given an SKSpriteNode

let sun = SKSpriteNode(imageNamed: "sun")

all you have to do it

sun.addGlow()

Sample Image

Add glowing effect to an SKSpriteNode

I created this extension to add a glow effect to an SKSpriteNode

Just add this to your project

extension SKSpriteNode {

func addGlow(radius: Float = 30) {
let effectNode = SKEffectNode()
effectNode.shouldRasterize = true
addChild(effectNode)
let effect = SKSpriteNode(texture: texture)
effect.color = self.color
effect.colorBlendFactor = 1
effectNode.addChild(effect)
effectNode.filter = CIFilter(name: "CIGaussianBlur", parameters: ["inputRadius":radius])
}
}

Now given an SKSpriteNode

let sun = SKSpriteNode(imageNamed: "sun")

all you have to do it

sun.addGlow()

Sample Image

Add glowing effect to an SKSpriteNode

I created this extension to add a glow effect to an SKSpriteNode

Just add this to your project

extension SKSpriteNode {

func addGlow(radius: Float = 30) {
let effectNode = SKEffectNode()
effectNode.shouldRasterize = true
addChild(effectNode)
let effect = SKSpriteNode(texture: texture)
effect.color = self.color
effect.colorBlendFactor = 1
effectNode.addChild(effect)
effectNode.filter = CIFilter(name: "CIGaussianBlur", parameters: ["inputRadius":radius])
}
}

Now given an SKSpriteNode

let sun = SKSpriteNode(imageNamed: "sun")

all you have to do it

sun.addGlow()

Sample Image

How to draw a line in Sprite-kit

Using SKShapeNode you can draw line or any shape.

SKShapeNode *yourline = [SKShapeNode node];
CGMutablePathRef pathToDraw = CGPathCreateMutable();
CGPathMoveToPoint(pathToDraw, NULL, 100.0, 100.0);
CGPathAddLineToPoint(pathToDraw, NULL, 50.0, 50.0);
yourline.path = pathToDraw;
[yourline setStrokeColor:[SKColor redColor]];
[self addChild:yourline];

Equivalent for Swift 4:

var yourline = SKShapeNode()
var pathToDraw = CGMutablePath()
pathToDraw.move(to: CGPoint(x: 100.0, y: 100.0))
pathToDraw.addLine(to: CGPoint(x: 50.0, y: 50.0))
yourline.path = pathToDraw
yourline.strokeColor = SKColor.red
addChild(yourline)


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