SceneKitMetalDidRenderScene.swift

func renderer(_ renderer: SCNSceneRenderer, didRenderScene scene: SCNScene, atTime time: TimeInterval) {
    // Used to encode additional rendering commands after SceneKit has drawn its content.
    guard let encoder = scnView.currentRenderCommandEncoder else { return }
    
    encoder.setRenderPipelineState(pipelineState)
    encoder.setVertexBuffer(vertexBuffer, offset: 0, index: 0)
    encoder.drawPrimitives(type: .triangle, vertexStart: 0, vertexCount: 3)
}