RealityKit – How to add a Video Material to a ModelEntity?

问题

I use the code to add a picture texture in RealityKit and it works fine.

var material = SimpleMaterial()

material.baseColor = try! .texture(.load(named: "image.jpg"))

I try to use this code to add a video file to be a texture, but it crashes!!!

guard let url = Bundle.main.url(forResource: "data", withExtension: "mp4") else {
    return
}
material.baseColor = try! .texture(.load(contentsOf: url))

How can I add a video file?

回答1:

You can use video textures only in RealityKit 2.0 (Xcode 12 with iOS 14 target is needed). A previous version of RealityKit doesn't support video materials.

Here's a code showing you how to apply it:

import AVKit
import RealityKit

@IBOutlet var arView: ARView!

// AVPLAYER
guard let pathToVideo = Bundle.main.path(forResource: "video", ofType: "mp4") 
else { 
    return 
}
let videoURL = URL(fileURLWithPath: pathToVideo)
let avPlayer = AVPlayer(url: videoURL)

// ENTITY
let mesh = MeshResource.generatePlane(width: 1.92, depth: 1.08)    // 16:9 video
let material = VideoMaterial(avPlayer: avPlayer)
let planeEntity = ModelEntity(mesh: mesh, materials: [material])

// ANCHOR
let anchor = AnchorEntity(.plane(.vertical,
                            classification: .wall,
                             minimumBounds: [0.3, 0.3])
anchor.addChild(planeEntity)
arView.scene.anchors.append(anchor)

// PLAYBACK
avPlayer.play()

Also, you can add VideoMaterial this way:

// AVPLAYER and PlayerItem
let url = Bundle.main.url(forResource: "aaa",
                        withExtension: "mp4")
let asset = AVAsset(url: url!)
let playerItem = AVPlayerItem(asset: asset)
let avPlayer = AVPlayer()
    
// ENTITY
let mesh = MeshResource.generateSphere(radius: 1)
let material = VideoMaterial(avPlayer: avPlayer)
let entity = ModelEntity(mesh: mesh, materials: [material])
    
// ANCHOR
let anchor = AnchorEntity(world: [0,0,-10])
anchor.addChild(entity)
arView.scene.anchors.append(anchor)
    
// PLAYBACK
avPlayer.replaceCurrentItem(with: playerItem)
avPlayer.play()

回答2:

I found the workaround, such as below code

self.arView = arView
let scene = SCNScene()
scnView = SCNView(frame: arView.frame)
scnView?.scene = scene
scnView?.backgroundColor = UIColor.clear
scnView?.scene?.background.contents = UIColor.clear

Then add SCN camera and set camera transform from ARFrame, such as:

let rotation = SCNMatrix4MakeRotation(.pi / 2.0, 0, 0, 1)
        let cameraTransform = simd_mul(frame.camera.transform, simd_float4x4(rotation))

let projectionMatrix = SCNMatrix4(frame.camera.projectionMatrix(for: .portrait,
                                                                         viewportSize: self.viewBounds!.size,
                                                                         zNear: 0.001,
                                                                         zFar: 10000) )
self.arCameraNode?.simdTransform = cameraTransform
self.arCameraNode?.camera?.projectionTransform = projectionMatrix

Finally, add your SCN video node into rootNode
However, there is a little shifting, I think you can wait for Realitykit to support video material.

回答3:

I might be wrong, but currently RealityKit does not support videos. A video is not a normal texture, it is a set of animated textures.

来源：https://stackoverflow.com/questions/58131206/realitykit-how-to-add-a-video-material-to-a-modelentity

标签

swift

augmented-reality

arkit

realitykit