I'm trying to use a spotlight in my scene and add shadows to an object. However, I noticed that when I increase the spotInnerAngle, the shadow of the object changes significantly. Here's an example:
Both of shadows in these images look quite different – does anyone know why increasing the spot angle is causing the shadow to be less apparent?
This is the code I'm using to create a spotlight/add shadows to my scene:
let spotLight = SCNNode()
spotLight.light = SCNLight()
spotLight.light?.type = SCNLight.LightType.spot
spotLight.light?.spotInnerAngle = 120
spotLight.light?.spotOuterAngle = 120
spotLight.light?.color = UIColor.white
spotLight.light?.castsShadow = true
spotLight.light?.automaticallyAdjustsShadowProjection = true
spotLight.light?.shadowSampleCount = 32
spotLight.light?.shadowRadius = 8
spotLight.light?.shadowMode = .deferred
spotLight.light?.shadowMapSize = CGSize(width: 2048, height: 2048)
spotLight.light?.shadowColor = UIColor.black.withAlphaComponent(1)
spotLight.position = SCNVector3(x: 0,y: 5,z: 0)
spotLight.eulerAngles = SCNVector3(-Float.pi / 2, 0, 0)
SceneKit's engine calculates shadows slightly differently than 3D software apps do, like Maya or 3dsMax. In SceneKit framework the position and scale of your Spotlight as well as its value of cone angle are crucial for shadow generating. The main rule is the following: when area of spotlight's ray in SceneKit becomes greater, the shadow edges become more obscure (aka blurry).
Here's a properties you have to take into consideration when using spotlight:
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light!.type = .spot
lightNode.rotation = SCNVector4(x: 0, y: 0, z: 0, w: 1)
lightNode.castsShadow = true
/* THESE SEVEN SPOTLIGHT PROPERTIES AFFECT SHADOW'S APPEARANCE */
lightNode.position = SCNVector3(0, 10, 0)
lightNode.scale = SCNVector3(7, 7, 7)
lightNode.light?.spotOuterAngle = 120
lightNode.light?.shadowRadius = 10
lightNode.light?.zNear = 0
lightNode.light?.zFar = 1000000
lightNode.light?.shadowSampleCount = 20
lightNode.light?.shadowColor = UIColor(write: 0, alpha: 0.75)
lightNode.light?.shadowMode = .deferred
scene.rootNode.addChildNode(lightNode)
Also, I recommend you use Ambient Light with very low Intensity for lighting up dark areas on your 3D models.
Hope this helps.
From Apple's documentation:
"[spotInnerAngle] determines the width of the fully illuminated area."
The default value of this property is 0, which means only the center of the area illuminated by the spotlight is lit at full intensity.
Increasing the inner angle will increase the area that is lit at full intensity, thus adding more light to the scene. In your case, this additional light was decreasing the visible shadow from that angle.
Related
I have an AR app in which I have calculated current sun position from the user. I reduced this position to distance of 10,000 meters, so it kinda "stays" in place when I move inside the scene. Now I would like to cast shadows from this node on other nodes inside my scene. I tried few types of lightning, but none was successful. Some didn't drop shadow at all, others behave strange. What would be the best method to create a light source from such distant node to cast shadows on invisible floor node? Should I also add ambient light to the scene? Can it be added to camera node, or should be somewhere else?
Use directional light for Sun simulation (Sun has parallel rays that for us are primary rays from very distant light source) and use ambient light for simulating fake secondary rays (in case you do not use Global Illumination).
// DIRECTIONAL LIGHT for `primary light rays` simulation
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light!.type = .directional
lightNode.light!.castsShadow = true
lightNode.light!.shadowMode = .deferred
lightNode.light!.categoryBitMask = -1
lightNode.light!.automaticallyAdjustsShadowProjection = true
//lightNode.light!.maximumShadowDistance = 11000
lightNode.position = SCNVector3(x: 0, y: -5000, z: 0)
lightNode.rotation = SCNVector4(x: -1, y: 0, z: 0, w: .pi/2)
scene.rootNode.addChildNode(lightNode)
Tip: The position of directional light could be any (in the following code it is even under the plane y:-5000), the most important thing is direction of directional light!
Also directional light has no falloff parameter or, so called, quadratic light decay.
// AMBIENT LIGHT for `fake secondary light rays` simulation
let ambientLightNode = SCNNode()
ambientLightNode.light = SCNLight()
ambientLightNode.light!.type = .ambient
ambientLightNode.light!.intensity = 1000
ambientLightNode.light!.color = NSColor.white
scene.rootNode.addChildNode(ambientLightNode)
Do not mistakenly use this Boolean value:
lightNode.castsShadow = true
instead of this one:
lightNode.light!.castsShadow = true
The Boolean value lightNode.castsShadow determines whether SceneKit renders the node’s contents into shadow maps.
And here's a screenshot if you wish to enable shadows in manually created directional light:
Sometimes, you get some benefits if you attach a light to the camera. In that case object's surfaces with normals parallel to light's rays are lit.
I have an ARKit scene with an invisible SCNPlane:
plane.geometry?.firstMaterial?.colorBufferWriteMask = []
This plane is placed on the ground and is used to render deferred shadows from other objects placed in the scene.
I want to render another SCNPlane which should be on the same level as the invisible plane (same Z-coordinate). The problem is, that every time the new object is under the invisible plane, it is not rendered at all.
Is there any way to render the object when it is under the invisible plane?
You can achieve it using the following lines of code:
shadowsPlane.geometry?.materials.first?.writesToDepthBuffer = true
shadowsPlane.geometry?.materials.first?.readsFromDepthBuffer = true
Choose one of two instance properties for .colorBufferWriteMask:
shadowsPlane.geometry?.materials.first?.colorBufferWriteMask = []
Set a rendering order for your objects like:
shadowsPlane.renderingOrder = -1 // the nearest layer
And, of course, use an appropriate .lightingModel instance property:
shadowsPlane.geometry?.materials.first?.lightingModel = .constant
Remember, there will be some tiny air gap between two planes:
shadowsPlane.position = SCNVector3(x: 0, y: 0, z: 0)
floorPlane.position = SCNVector3(x: 0, y: -0.01, z: 0)
Blocks just crumble apart.
How can this problem be solved?
Initializing blocks:
var boxNode = SCNNode(geometry: SCNBox(width: 0.75, height: 0.15, length: 0.25, chamferRadius: 0))
boxNode.position = SCNVector3(x: x1, y: y, z: z1)
boxNode.geometry?.firstMaterial = SCNMaterial()
boxNode.geometry?.firstMaterial?.diffuse.contents = UIImage(named: "wood.jpg")
boxNode.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
boxNode.eulerAngles.y = Float(Double.pi / 2) * rotation
boxNode.physicsBody?.friction = 1
boxNode.physicsBody?.mass = 0.5
boxNode.physicsBody?.angularDamping = 1.0
boxNode.physicsBody?.damping = 1
picture
video
full code
I won't be able to tell you how to fix it as I have the exact same problem which I wasn't able to solve. However, as I played around I figured out a couple of things (which you may find useful):
The same problem hasn't happened to me in pure SceneKit, hence I think it's a bug in ARKit
Node with physics has to be added to the rootNode of the scene, otherwise odd stuff happens (elements passing through each other, gravity behaving in an inconsistent way)
If you pass nil as shape parameter, SceneKit will figure bounding box based on the geometry of the node. This hasn't worked properly for me so what I've done (using SceneKit editor) was to duplicate the geometry and then set it as a custom shape for the bounding box (have a look at the attached image)
Overall I've found physics simulation in SceneKit when used with ARKit to be extremely buggy and I spent a lot of time "tricking" it into working more-or-less how I wanted it to work.
Apologies in advance as I'm not sure exactly what the right question is. The problems that I'm ultimately trying to address are:
1) Game gets laggy at times
2) CPU % can get high, as much as 50-60% at times, but is also sometimes relatively low (<20%)
3) Device (iPhone 6s) can get slightly warm
I believe what's driving the lagginess is that I'm constantly creating and removing circles in the SKScene. It's pretty much unavoidable because the circles are a critical element to the game and I have to constantly change their size and physicsBody properties so there's not much I can do in terms of reusing nodes. Additionally, I'm moving another node almost constantly.
func addCircle() {
let attributes = getTargetAttributes() //sets size, position, and color of the circle
let target = /*SKShapeNode()*/SKShapeNode(circleOfRadius: attributes.size.width)
let outerPathRect = CGRect(x: 0, y: 0, width: attributes.size.width * 2, height: attributes.size.width * 2)
target.position = attributes.position
target.fillColor = attributes.color
target.strokeColor = attributes.stroke
target.lineWidth = 8 * attributes.size.width / 35
target.physicsBody = SKPhysicsBody(circleOfRadius: attributes.size.width)
addStandardProperties(node: target, name: "circle", z: 5, contactTest: ContactCategory, category: CircleCategory) //Sets physicsBody properties
addChild(target)
}
The getAttributes() function is not too costly. It does have a while loop to set the circle position, but it doesn't usually get used when the function is called. Otherwise, it's simple math.
Some other details:
1) The app runs at a constant 120 fps. I've tried setting the scene/view lower by adding view.preferredFramesPerSecond = 60 in GameScene.swift and gameScene.preferredFramesPerSecond = 60 in GameViewController. Neither one of these does anything to change the fps. Normally when I've had performance issues in other apps, the fps dipped, however, that isn't happening here.
2) I’ve tried switching the SKShapeNode initializer to use a path versus circleOfRadius and then resetting the path. I’ve also tried images, however, because I have to reset the physicsBody, there doesn’t appear to be a performance gain.
3) I tried changing the physicsWorld speed, but this also had little effect.
4) I've also used Instruments to try to identify the issue. There are big chunks of resources being used by SKRenderer, however, I can't find much information on this.
Creating SKShapeNodes are inefficient, try to use it as few times as you can. instead, create a template shape, and convert it to an SKSpriteNode.
If you need to change the size, then use xScale and yScale, if you need to change the color, then use color with colorBlendFactor of 1
If you need to have a varying color stroke, then change the below code to have 2 SKSpriteNodes, 1 SKSpriteNode that handles only the fill, and 1 SKSpriteNode that handles only the stroke. Have the stroke sprite be a child of the fill sprite with a zPosition of 0 and set the stroke color to white. You can then apply the color and colorBlendFactor to the child node of the circle to change the color.
lazy var circle =
{
let target = SKShapeNode(circleOfRadius: 1000)
target.fillColor = .white
//target.strokeColor = .black //if stroke is anything other than black, you may need to do 2 SKSpriteNodes that layer each other
target.lineWidth = 8 * 1000 / 35
let texture = SKView().texture(from:target)
let spr = SKSpriteNode(texture:texture)
spr.physicsBody = SKPhysicsBody(circleOfRadius: 1000)
addStandardProperties(node: spr, name: "circle", z: 5, contactTest:ContactCategory, category: CircleCategory) //Sets physicsBody properties
return spr
}()
func createCircle(of radius:CGFloat,color:UIColor) -> SKSpriteNode
{
let spr = circle.copy()
let scale = radius/1000.0
spr.xScale = scale
spr.yScale = scale
spr.color = color
spr.colorBlendFactor = 1.0
return spr
}
func addCircle() {
let attributes = getTargetAttributes() //sets size, position, and color of the circle
let spr = createCircle(of:attribute.width,color:attributes.color)
spr.position = attributes.position
addChild(str)
}
The documentation for SceneKit's collisionBitMask property of SCNPhysicsBody states the following:
When two physics bodies contact each other, a collision may occur.
SceneKit compares the body’s collision mask to the other body’s
category mask by performing a bitwise AND operation. If the result is
a nonzero value, then the body is affected by the collision. Each body
independently chooses whether it wants to be affected by the other
body.
That last line indicates that if I have two objects, I can set it up so that when they collide, only one of them should be affected by the collision.
let CollisionCategoryPlane = 1 << 0
let CollisionCategorySphere1 = 1 << 1
let CollisionCategorySphere2 = 1 << 2
let plane = SCNNode(geometry: SCNPlane(width: 10, height: 10))
plane.position = SCNVector3(x: 0, y: -10, z: 0)
plane.eulerAngles = SCNVector3(x: Float(-M_PI/2), y: 0, z: 0)
plane.physicsBody = SCNPhysicsBody.staticBody()
plane.physicsBody?.categoryBitMask = CollisionCategoryPlane
plane.physicsBody?.collisionBitMask = CollisionCategorySphere1 | CollisionCategorySphere2
// the plane should be affected by collisions with both spheres (but the plane is static so it doesn't matter)
scene.rootNode.addChildNode(plane)
let sphere1 = SCNNode(geometry: SCNSphere(radius: 1))
sphere1.physicsBody = SCNPhysicsBody.dynamicBody()
sphere1.physicsBody?.categoryBitMask = CollisionCategorySphere1
sphere1.physicsBody?.collisionBitMask = CollisionCategoryPlane
// sphere1 should only be affected by collisions with the plane, not with sphere2
scene.rootNode.addChildNode(sphere1)
let sphere2 = SCNNode(geometry: SCNSphere(radius: 1))
sphere2.position = SCNVector3(x: 1, y: 10, z: 0)
sphere2.physicsBody = SCNPhysicsBody.dynamicBody()
sphere2.physicsBody?.categoryBitMask = CollisionCategorySphere2
sphere2.physicsBody?.collisionBitMask = CollisionCategoryPlane | CollisionCategorySphere1
// sphere2 should be affected by collisions with the plane and sphere1
scene.rootNode.addChildNode(sphere2)
Sphere1 should fall onto the plane, then sphere2 should fall onto sphere1 and bounce off, and sphere1 should be unaffected by the collision with sphere2. However, the observed behaviour is both spheres falling onto the plane and coming to rest inside each other - no collision event between the two spheres is registered.
What is going on here?
On related notes, some even stranger behaviour is observed when I make a couple small modifications to the above code.
If remove the line that defines the plane's collsionBitMask, leaving it as the default SCNPhysicsCollisionCategoryAll, sphere1 no longer collides with the plane.
If I move the lines that define the objects' physics bodies, categoryBitMasks, and collisionBiMasks to after the objects have each been added to the the scene, all the objects will collide with every other object. Even if I set every collisionBitMask to zero.