CODEWITHSUNDEEP
iosswiftsprite-kitscenekit
khabiroff
khabiroff

Reputation: 240

SKScene in SCNMaterial's contents appears upside down

I am trying to have an SCNNode with plane geometry, which presents 2d text inside it. I'm doing that through setting SKLabelNode as geometry's material (took that from here)

Here's my code:

let label = SKLabelNode(text: "Test Text 1")
label.fontColor = .white
label.fontName = UIFont.systemFont(ofSize: 32).fontName
label.fontSize = 32

let backgroundRectShape = SKShapeNode(rect: CGRect(origin: .zero, size: label.frame.size))
backgroundRectShape.fillColor = .orange
backgroundRectShape.addChild(label)
label.position = CGPoint(x: backgroundRectShape.frame.width / 2, y: 0)

let skScene = SKScene(size: label.frame.size)
skScene.addChild(backgroundRectShape)
backgroundRectShape.position = .zero

let plane = SCNPlane(width: label.frame.width / 10, height: label.frame.height / 10)
plane.firstMaterial?.diffuse.contents = skScene
let node = SCNNode(geometry: plane)

scene.rootNode.addChildNode(node)

Everything seems fine, but the SKLabelNode appears upside-down: Screenshot 1

The SCNNode is surely properly aligned and not rotated, because when I set an image as material content, everything is ok: Screenshot 2

I just can't understand why it is happening. The easiest solution would be setting SKLabelNode's yScale to -1, but I don't want to do that without understanding the reason why it appears upside down by default.

Upvotes: 9

Views: 940

Answers (2)

Bobby
Bobby

Reputation: 6255

plane.firstMaterial?.diffuse.contentsTransform = SCNMatrix4Translate(SCNMatrix4MakeScale(1, -1, 1), 0, 1, 0)

Upvotes: 6

Andy Jazz
Andy Jazz

Reputation: 58563

It is seemingly a bug or one of the many limitations of SpriteKit/SceneKit framework.

I suppose SCNMaterial's content erroneously appears upside-down due to the origin of iOS coordinate system.

enter image description here

But instead of scaling the SCNNode itself you should better mirror a texture along Y-axis using contentsTransform instance property of the SCNMaterial. Like so:

material.diffuse.contentsTransform = SCNMatrix4MakeScale(1, -1, 1)

Hope this helps.

Upvotes: 1

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