TextureListener.kt

    private val surfaceTextureListenerFront = object : TextureView.SurfaceTextureListener {
        override fun onSurfaceTextureAvailable(texture: SurfaceTexture, width: Int, height: Int) {
            openCameraFront(width, height)
        }
        override fun onSurfaceTextureSizeChanged(texture: SurfaceTexture, width: Int, height: Int) {
            configureTransformFront(width, height)
        }
        override fun onSurfaceTextureDestroyed(texture: SurfaceTexture) = true
        override fun onSurfaceTextureUpdated(texture: SurfaceTexture) = Unit
    }

    private val surfaceTextureListenerRear = object : TextureView.SurfaceTextureListener {
        override fun onSurfaceTextureAvailable(texture: SurfaceTexture, width: Int, height: Int) {
            openCameraRear(width, height)
        }
        override fun onSurfaceTextureSizeChanged(texture: SurfaceTexture, width: Int, height: Int) {
            configureTransformRear(width, height)
        }
        override fun onSurfaceTextureDestroyed(texture: SurfaceTexture) = true
        override fun onSurfaceTextureUpdated(texture: SurfaceTexture) = Unit
    }