cylinder elevator

ViewController.m

//
//  ViewController.m
//  CylinderElevator
//
//  Created by MizushimaYusuke on 9/17/15.
//  Copyright (c) 2015 MizushimaYusuke. All rights reserved.
//

#import "ViewController.h"
@import SceneKit;

@interface ViewController () <SCNPhysicsContactDelegate, SCNSceneRendererDelegate>
@property (nonatomic, weak) SCNView *sceneView;
@property (nonatomic, weak) SCNNode *player;
@property (nonatomic, weak) SCNNode *elevator;
@property (nonatomic, weak) SCNNode *camera;
@property (nonatomic) BOOL up;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setupScene];
    [self createGround];
    [self createCylinder];
    [self createElevator];
    [self createPlayer];
    [self createCamera];
}

- (void)setupScene {
    SCNView *sv = [[SCNView alloc] initWithFrame:self.view.bounds];
    sv.backgroundColor = [UIColor colorWithHue:0.6 saturation:0.1 brightness:1 alpha:1];
    sv.scene = [SCNScene scene];
    sv.autoenablesDefaultLighting = YES;
    sv.allowsCameraControl = YES;
    [self.view addSubview:sv];
    
    sv.delegate = self;
    sv.scene.physicsWorld.contactDelegate = self;
    
    self.sceneView = sv;
}

- (void)createGround {
    SCNBox *b = [SCNBox boxWithWidth:10 height:1 length:10 chamferRadius:0];
    b.firstMaterial.diffuse.contents = [UIColor lightGrayColor];
    SCNNode *bNode = [SCNNode nodeWithGeometry:b];
    bNode.position = SCNVector3Make(0, -4, 0);
    bNode.physicsBody = [SCNPhysicsBody staticBody];
    [self.sceneView.scene.rootNode addChildNode:bNode];
}

- (void)createCylinder {
    SCNCylinder *c = [SCNCylinder cylinderWithRadius:2 height:8];
    c.firstMaterial.diffuse.contents = [UIColor lightGrayColor];
    SCNNode *cNode = [SCNNode nodeWithGeometry:c];
    cNode.physicsBody = [SCNPhysicsBody staticBody];
    cNode.physicsBody.friction = 1;

    SCNPhysicsHingeJoint *pin = [SCNPhysicsHingeJoint jointWithBody:cNode.physicsBody axis:SCNVector3Make(0, 1, 0) anchor:SCNVector3Zero];
    [self.sceneView.scene.physicsWorld addBehavior:pin];
    
    [self.sceneView.scene.rootNode addChildNode:cNode];
}

- (void)createElevator {
    SCNBox *box = [SCNBox boxWithWidth:2 height:0.02 length:2 chamferRadius:0];
    box.firstMaterial.diffuse.contents = [UIColor redColor];
    SCNNode *elevator = [SCNNode nodeWithGeometry:box];
    elevator.position = SCNVector3Make(0, -3.3, 3);
    elevator.physicsBody = [SCNPhysicsBody dynamicBody];
    elevator.physicsBody.angularVelocityFactor = SCNVector3Make(0, 0, 0);
    [self.sceneView.scene.rootNode addChildNode:elevator];
    self.elevator = elevator;

}

- (void)createPlayer {
    SCNBox *p = [SCNBox boxWithWidth:1 height:1 length:1 chamferRadius:0.1];
    p.firstMaterial.diffuse.contents = [UIColor yellowColor];
    SCNNode *pNode = [SCNNode nodeWithGeometry:p];
    pNode.position = SCNVector3Make(-4, 0, 3);
    pNode.physicsBody = [SCNPhysicsBody dynamicBody];
    pNode.physicsBody.friction = 1;
    [self.sceneView.scene.rootNode addChildNode:pNode];
    
    self.player = pNode;
}

- (void)createCamera {
    SCNNode *camera = [SCNNode node];
    camera.camera = [SCNCamera camera];
    camera.rotation = SCNVector4Make(1, 0, 0, -0.4);
    [self.sceneView.scene.rootNode addChildNode:camera];
    
    self.camera = camera;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self.player.physicsBody applyForce:SCNVector3Make(2.2, 3, 0) impulse:YES];
}

- (void)physicsWorld:(SCNPhysicsWorld *)world didBeginContact:(SCNPhysicsContact *)contact {
    if ((contact.nodeA == self.player && contact.nodeB == self.elevator)
        || (contact.nodeB == self.player && contact.nodeA == self.elevator)) {
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            self.up = YES;
        });
    }
}

- (void)renderer:(id<SCNSceneRenderer>)aRenderer updateAtTime:(NSTimeInterval)time {
    if (self.up) {
        float vx = self.elevator.presentationNode.position.z;
        float vz = -self.elevator.presentationNode.position.x;
        self.elevator.physicsBody.velocity = SCNVector3Make(vx, 1, vz);
    }
    
    self.camera.position = SCNVector3Make(0, self.player.presentationNode.position.y + 5, 10);
}

@end