TwoBoxes.swift

//
//  GameViewController.swift
//  WordMatch
//
//  Created by Dan Appel on 12/17/15.
//  Copyright (c) 2015 Dan Appel. All rights reserved.
//

import UIKit
import QuartzCore
import SceneKit

class GameViewController: UIViewController {

    var boxNode = SCNNode()
    typealias Vector2 = (x: Float, y: Float)
    var rotationAngle = Vector2(x: 0, y: 0)
    var distance: Double = 1
    
    var scnView: SCNView {
        return self.view as! SCNView
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()

        setupScene()
        
        setupBox()
        
        lights()
        camera()
        action()
    }
    
    func setupScene() {
        
        let scene = SCNScene()
        
        scnView.scene = scene
        scnView.showsStatistics = true
        scnView.allowsCameraControl = true
    }
    
    func setupBox() {
        
        let box1 = SCNBox(width: 10, height: 10, length: 10, chamferRadius: 1.0)
        let box2 = SCNBox(width: 10, height: 10, length: 10, chamferRadius: 1.0)
        
        let subBoxNode1 = SCNNode(geometry: box1)
        subBoxNode1.transform = SCNMatrix4MakeTranslation(7, 0, 0)
        
        let subBoxNode2 = SCNNode(geometry: box2)
        subBoxNode2.transform = SCNMatrix4MakeTranslation(-7, 0, 0)
        boxNode.addChildNode(subBoxNode1)
        boxNode.addChildNode(subBoxNode2)
        scnView.scene!.rootNode.addChildNode(boxNode)
    }
    
    func lights() {
        let ambientLightNode = SCNNode()
        let ambientLight = SCNLight()
        ambientLight.type = SCNLightTypeAmbient
        ambientLight.color = UIColor(white: 0.67, alpha: 1)
        ambientLightNode.light = ambientLight
        scnView.scene!.rootNode.addChildNode(ambientLightNode)
        
        let omniLightNode = SCNNode()
        let omniLight = SCNLight()
        omniLight.type = SCNLightTypeOmni
        omniLight.color = UIColor(white: 0.3, alpha: 1)
        omniLightNode.light = omniLight
        omniLightNode.position = SCNVector3Make(0, 50, 50)
        scnView.scene!.rootNode.addChildNode(omniLightNode)
    }
    
    func camera() {
        let cameraNode = SCNNode()
        let camera = SCNCamera()
        cameraNode.camera = camera
        cameraNode.position = SCNVector3Make(0, 0, 50)
        scnView.scene!.rootNode.addChildNode(cameraNode)
    }
    
    func action() {
        let panGesture = UIPanGestureRecognizer(target: self, action: "handlePan:")
        scnView.addGestureRecognizer(panGesture)
    }

    func handlePan(gestureRecognizer: UIPanGestureRecognizer) {
        
        let translation = gestureRecognizer.translationInView(gestureRecognizer.view!)
        
        // for some reason these are flipped
        let xAngle = translation.y.toRadians() + rotationAngle.x
        let yAngle = translation.x.toRadians() + rotationAngle.y
        
        let xRotation = SCNMatrix4MakeRotation(xAngle, 1, 0, 0)
        let yRotation = SCNMatrix4MakeRotation(yAngle, 0, 1, 0)
        
        let rotation = SCNMatrix4Mult(xRotation, yRotation)
        
        boxNode.transform = rotation
        
        if gestureRecognizer.state == .Ended {
            rotationAngle.x += xAngle
            rotationAngle.y += yAngle
            
            // 2 radians per circle, therefore radians % 2 gives us actual rotation
            rotationAngle.x = rotationAngle.x % 2
            rotationAngle.y = rotationAngle.y % 2
        }
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Release any cached data, images, etc that aren't in use.
    }

}

extension CGFloat {
    func toRadians() -> Float {
        // 1 pixel = 1 degree
        
        // degrees -> radians:
        // 
        //              π radians
        //  degree  x  -----------   = radians
        //             180 degrees
        //
        // ex: 180 degrees -> pi radians
        
        return Float(self) * Float(M_PI)/180.0
    }
}

extension CGVector {
    var x: Float {
        return Float(self.dx)
    }
    var y: Float {
        return Float(self.dy)
    }
}