EngineActivity.kt

class EngineActivity : AppCompatActivity() {
    lateinit var engine: Engine
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_engine)
        engine = Engine()
        val renderView = findViewById<SurfaceView>(R.id.renderView)
        engine.initEngine()
        renderView.setZOrderOnTop(true);
        renderView.holder.addCallback(object: SurfaceHolder.Callback{
            override fun surfaceCreated(p0: SurfaceHolder) {
                engine.createSwapChain(p0.surface)
                Choreographer.getInstance().postFrameCallback(FrameCallback())
            }

            override fun surfaceChanged(p0: SurfaceHolder, p1: Int, p2: Int, p3: Int) {
                engine.createSwapChain(p0.surface)
            }

            override fun surfaceDestroyed(p0: SurfaceHolder) {
            }

        })
    }

    inner class FrameCallback : Choreographer.FrameCallback {
        override fun doFrame(frameTimeNanos: Long) {
            // Schedule the next frame
            Choreographer.getInstance().postFrameCallback(this)
            engine.renderFrame()
        }
    }
}