iOS Scenekit Neon Glow

Xcode SceneKit Making a glowing light box

Make an omni light in the same position as your SCNNode. And set the value of the emission of the SCNNode the same colour as your light.

let box = SCNBox.init(width: 1, height: 1, length: 1, chamferRadius: 0.3)
box.materials.first?.diffuse.contents = UIColor.blue
box.materials.first?.emission.contents = UIColor.white
box.materials.first?.emission.intensity = 1.0
let boxNode = SCNNode.init(geometry: box)
boxNode.position = SCNVector3(x: 0, y: 0, z: -10)
self.sceneView.scene?.rootNode.addChildNode(boxNode)

let omniLight = SCNLight()
omniLight.type = .omni
omniLight.color = UIColor.yellow
boxNode.light = omniLight

SceneKit ARKit glowing effect

Have you tried setting the writesToDepthBuffer to false for those nodes which you aren't apply the filters to?

For your information writesToDepthBuffer refers to:

SceneKit’s rendering process uses a depth buffer to determine the
ordering of rendered surfaces relative to the viewer. The default
value of this property is YES, specifying that SceneKit saves depth
information for each rendered pixel for use by later rendering passes.
Typically, you disable writing to the depth buffer when rendering
semitransparent objects, because later stages of the rendering process
may require depth information about the opaque objects behind them.

This example seems to be working fine:

/// Generates An SCNPlane & A Red & Green SCNSphere
func generateNodes(){

    let planeNode = SCNNode(geometry: SCNPlane(width: 1, height: 0.5))
    planeNode.geometry?.firstMaterial?.diffuse.contents = UIColor.black
    planeNode.position = SCNVector3(0, 0, -1)

    let redSphereNode = SCNNode(geometry: SCNSphere(radius: 0.1))
    redSphereNode.geometry?.firstMaterial?.diffuse.contents = UIColor.red
    redSphereNode.position = SCNVector3(-0.3, 0, -1)
    redSphereNode.filters = addBloom()

    let greenSphereNode = SCNNode(geometry: SCNSphere(radius: 0.1))
    greenSphereNode.geometry?.firstMaterial?.diffuse.contents = UIColor.green
    greenSphereNode.position = SCNVector3(0.3, 0, -1)
    greenSphereNode.filters = addBloom()

    self.augmentedRealityView.scene.rootNode.addChildNode(planeNode)
    self.augmentedRealityView.scene.rootNode.addChildNode(redSphereNode)
    self.augmentedRealityView.scene.rootNode.addChildNode(greenSphereNode)
    planeNode.geometry?.firstMaterial?.writesToDepthBuffer = false

}

/// Creates An Array Of CIBloom Filters
///
/// - Returns: [CIFilter]?
func addBloom() -> [CIFilter]? {
    let bloomFilter = CIFilter(name:"CIBloom")!
    bloomFilter.setValue(10.0, forKey: "inputIntensity")
    bloomFilter.setValue(30.0, forKey: "inputRadius")

    return [bloomFilter]
}

One thing to note however, which I did notice was that if I used an image with a transparent background for the contents of the SCNPlane it didn't work, although with another image it was fine.

Hope it points you in the right direction...

How to create a neon material using SCNMaterial in swift?

It's simple:

material.emission.contents = [NSColor greenColor];

all this does is make the material glow in it's own light.

If you wish to make other objects affected by this neon light,

you could add a light to your neon node like so:

SCNLight *mylight = [SCNLight light];
mylight.type = SCNLightTypeOmni;
mylight.color = [NSColor greenColor];
myNeonNode.light = mylight;

Hope that helped!

Note:

the power of the light can be controlled by the color you use:

Dark green will seem like a green light that is not so powerful.

Light green will seem like a green light that is more powerful.

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];
    }
}