tower camera

ViewController.m

//
//  ViewController.m
//  TowerCamera
//
//  Created by MizushimaYusuke on 8/30/15.
//  Copyright (c) 2015 MizushimaYusuke. All rights reserved.
//

#import "ViewController.h"
@import SceneKit;

@interface ViewController () <SCNSceneRendererDelegate>
@property (nonatomic, weak) SCNView *sceneView;
@property (nonatomic, weak) SCNNode *player;
@property (nonatomic, weak) SCNNode *cameraScene;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setupScene];
    [self createTower];
    [self createPlayer];
    [self createCamera];
}

- (void)setupScene {
    SCNView *sv = [[SCNView alloc] initWithFrame:self.view.bounds];
    sv.backgroundColor = [UIColor colorWithHue:0.6 saturation:0.3 brightness:1 alpha:1];
    sv.scene = [SCNScene scene];
    sv.autoenablesDefaultLighting = YES;
    sv.delegate = self;
    [self.view addSubview:sv];
    
    self.sceneView = sv;
}

- (void)createTower {
    
    SCNCylinder *ground = [SCNCylinder cylinderWithRadius:5 height:0.2];
    ground.firstMaterial.diffuse.contents = [UIColor brownColor];
    SCNNode *groundNode = [SCNNode nodeWithGeometry:ground];
    groundNode.position = SCNVector3Make(0, -5, 0);
    groundNode.physicsBody = [SCNPhysicsBody staticBody];
    [self.sceneView.scene.rootNode addChildNode:groundNode];
    
    SCNCylinder *tower = [SCNCylinder cylinderWithRadius:3.5 height:10];
    tower.firstMaterial.diffuse.contents = [UIColor brownColor];
    SCNNode *towerNode = [SCNNode nodeWithGeometry:tower];
    towerNode.name = @"tower";
    towerNode.physicsBody = [SCNPhysicsBody staticBody];
    [self.sceneView.scene.rootNode addChildNode:towerNode];
    
    float dw = M_PI / 5.0;
    for (int i=0; i<9; i++) {
        float y = i - 3.5;
        SCNBox *step = [SCNBox boxWithWidth:12 height:0.1 length:2 chamferRadius:0];
        step.firstMaterial.diffuse.contents = [UIColor brownColor];
        SCNNode *stepNode = [SCNNode nodeWithGeometry:step];
        stepNode.position = SCNVector3Make(0, y, 0);
        stepNode.rotation = SCNVector4Make(0, 1, 0, dw * i);
        stepNode.physicsBody = [SCNPhysicsBody staticBody];
        [self.sceneView.scene.rootNode addChildNode:stepNode];
    }
}

- (void)createPlayer {
    SCNSphere *player = [SCNSphere sphereWithRadius:0.3];
    player.firstMaterial.diffuse.contents = [UIColor greenColor];
    SCNNode *playerNode = [SCNNode nodeWithGeometry:player];
    playerNode.name = @"player";
    playerNode.position = SCNVector3Make(0, -4, 4.5);
    playerNode.physicsBody = [SCNPhysicsBody dynamicBody];
    [self.sceneView.scene.rootNode addChildNode:playerNode];
    
    SCNPhysicsSliderJoint *motor = [SCNPhysicsSliderJoint jointWithBody:playerNode.physicsBody axis:SCNVector3Make(0, 1, 0) anchor:SCNVector3Make(0, -4, -4.5)];
    [self.sceneView.scene.physicsWorld addBehavior:motor];
    motor.motorMaximumTorque = 0.01;
    motor.motorTargetAngularVelocity = -0.3;
    
    self.player = playerNode;
}

- (void)createCamera {
    SCNNode *cs = [SCNNode node];
    [self.sceneView.scene.rootNode addChildNode:cs];
    
    SCNNode *camera = [SCNNode node];
    camera.camera = [SCNCamera camera];
    camera.position = SCNVector3Make(0, 0, 12);
    [cs addChildNode:camera];
    
    SCNLookAtConstraint *lc = [SCNLookAtConstraint lookAtConstraintWithTarget:self.player];
    lc.influenceFactor = 0.1;
    lc.gimbalLockEnabled = YES;
    camera.constraints = @[lc];
    self.cameraScene = cs;

}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self.player.physicsBody applyForce:SCNVector3Make(0, 5, 0) impulse:YES];
}

- (void)renderer:(id<SCNSceneRenderer>)aRenderer updateAtTime:(NSTimeInterval)time {
    self.cameraScene.rotation = self.player.presentationNode.rotation;
}

@end