HelloSceneKitController.cs

using System;
using MonoTouch.UIKit;
using MonoTouch.SceneKit;
using MonoTouch.Foundation;

namespace HelloSceneKit
{
    public class HelloSceneKitController : UIViewController
    {
        SCNView sceneView;
        SCNScene scene;
        SCNCamera camera;
        SCNNode cameraNode;
        SCNLight ambientLight;
        SCNNode ambientLightNode;
        SCNSphere sphere;
        SCNNode sphereNode;
        SCNMaterial material;

        UIButton animateButton;

        public override void ViewDidLoad ()
        {
            base.ViewDidLoad ();

            animateButton = UIButton.FromType (UIButtonType.System);
            animateButton.SetTitle ("Animate", UIControlState.Normal);
            animateButton.Frame = new System.Drawing.RectangleF (0, 0, 100, 50);
            animateButton.TouchUpInside += (sender, e) => {

                SCNTransaction.Begin ();
                SCNTransaction.AnimationDuration = 2.0;
                sphereNode.Rotation = new SCNVector4 (0, 1, 0, (float)Math.PI * 4);
                material.Shininess = 0.1f;
                SCNTransaction.Commit ();
            };

            scene = SCNScene.Create ();
            sceneView = new SCNView (View.Frame);
            sceneView.AutoresizingMask = UIViewAutoresizing.All;    
            sceneView.Scene = scene;

            // camera
            camera = new SCNCamera {
                XFov = 40,
                YFov = 40
            };
            cameraNode = new SCNNode {
                Camera = camera,
                Position = new SCNVector3 (0, 0, 40)
            };
            scene.RootNode.AddChildNode (cameraNode);
            
            // sphere
            sphere = SCNSphere.Create (10.0f);
            sphereNode = SCNNode.FromGeometry (sphere);
            sphereNode.Position = new SCNVector3 (0, 0, 0);
            scene.RootNode.AddChildNode (sphereNode);

            // ambient light
            ambientLight = SCNLight.Create ();
            ambientLightNode = SCNNode.Create ();
            ambientLight.LightType = SCNLightType.Ambient;
            ambientLight.Color = UIColor.Purple;
            ambientLightNode.Light = ambientLight;
            scene.RootNode.AddChildNode (ambientLightNode);

            // diffuse lights
            scene.RootNode.AddChildNode (CreateDiffuseLightNode (UIColor.Blue, new SCNVector3 (-40, 40, 60), SCNLightType.Omni));
            scene.RootNode.AddChildNode (CreateDiffuseLightNode (UIColor.Yellow, new SCNVector3 (20, 20, -70), SCNLightType.Omni));
            scene.RootNode.AddChildNode (CreateDiffuseLightNode (UIColor.Red, new SCNVector3 (20, -20, 40), SCNLightType.Omni));
            scene.RootNode.AddChildNode (CreateDiffuseLightNode (UIColor.Green, new SCNVector3 (-20, -40, 70), SCNLightType.Omni));
            
            // material
            material = SCNMaterial.Create ();
            material.Diffuse.Contents = UIImage.FromFile ("monkey.png");
            material.Specular.Contents = UIColor.White;
            sphere.Materials = new SCNMaterial[] { material };

            sceneView.AllowsCameraControl = true;

            View.AddSubview (sceneView);
            View.AddSubview (animateButton);
        }

        SCNNode CreateDiffuseLightNode (UIColor color, SCNVector3 position, NSString lightType)
        {
            var light = SCNLight.Create ();
            var lightNode = SCNNode.Create ();
            light.LightType = lightType;
            light.Color = color;
            lightNode.Light = light;
            lightNode.Position = position;
            return lightNode;
        }
    }
}