Get preview image from dae file, to display in UIImage - swift

Question

I'm building an augmented reality app and would like to show preview images of the available DAE files.
Is it possible to use Swift to extract image data from a DAE file and to load that into an UIImage?

Answer 1

Out of the box there is no function to call that will pull a screen shot from a .dae file. Thats not to say that there isn't a way to do this on device.
To understand what you are asking lets consider the different components.
The .dae file is loaded using an ARSCNView, which is a reader for .dae files. The ARSCNView is traditionally added as a subview to your ViewController. In this instance you would need the viewer to render the 3D file offscreen so you need to create an ARSCNView but do not add it as a subview of the VC (i would add it during the initial setup to make sure it all loads, but then comment that line out)
Once you have your 3D loaded into your ARSCNView, use the below function to rip the context of the view into a JPG image
let viewSnapshot = takeSnapshotOfView(view: yourARSCNView)
and to rip the context and resize the JPG:
import UIKit
import CoreGraphics
func takeSnapshotOfView(view:UIView) -> UIImage? {
UIGraphicsBeginImageContext(CGSize(width: view.frame.size.width, height: view.frame.size.height))
view.drawHierarchy(in: CGRect(x: 0.0, y: 0.0, width: view.frame.size.width, height: view.frame.size.height), afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image?.resize(CGRect(x: 0, y: 0, width: 300, height: (image?.size.height)! / 300 * (image?.size.width)!)) // resize image before returning
}
extension UIImage {
func resize(_ toSize: CGRect) -> UIImage {
let size = self.size
let widthRatio = toSize.width / self.size.width
let heightRatio = toSize.height / self.size.height
var newSize: CGSize
if widthRatio > heightRatio {
newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio)
} else {
newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio)
}
let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)
UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
self.draw(in: rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
}