/*

 Copyright (C) 2016 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 View Controller for Metal Sample Code. Maintains a CADisplayLink timer that runs on the main thread and triggers rendering in AAPLView. Provides update callbacks to its delegate on the timer, prior to triggering rendering.

 */

#import <UIKit/UIKit.h>

@protocol AAPLViewControllerDelegate;

@interface AAPLViewController : UIViewController

@property (nonatomic, weak) IBOutlet id <AAPLViewControllerDelegate> delegate;

// the time interval from the last draw

@property (nonatomic, readonly) NSTimeInterval timeSinceLastDraw;

// What vsync refresh interval to fire at. (Sets CADisplayLink frameinterval property)

// set to 1 by default, which is the CADisplayLink default setting (60 FPS).

// Setting to 2, will cause gameloop to trigger every other vsync (throttling to 30 FPS)

@property (nonatomic) NSUInteger interval;

// Used to pause and resume the controller.

@property (nonatomic, getter=isPaused) BOOL paused;

// used to fire off the main game loop

- (void)dispatchGameLoop;

// use invalidates the main game loop. when the app is set to terminate

- (void)stopGameLoop;

@end

// required view controller delegate functions.

@protocol AAPLViewControllerDelegate <NSObject>

@required

// Note this method is called from the thread the main game loop is run

- (void)update:(AAPLViewController *)controller;

// called whenever the main game loop is paused, such as when the app is backgrounded

- (void)viewController:(AAPLViewController *)controller willPause:(BOOL)pause;

@end