/*

 Copyright (C) 2015-2016 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Application view controller implementing Metal Kit delgates.

 */

#import <cmath>

#import "NBodyVisualizer.h"

#import "AppViewController.h"

@implementation AppViewController

{

@private

    // Default Metal system devive

    id<MTLDevice>  device;

    // Metal-Kit view

    MTKView*  mpView;

    // N-body simulation visualizer object

    NBodyVisualizer*  mpVisualizer;

}

- (void) _update:(nonnull MTKView *)view

{

    const CGRect bounds = view.bounds;

    const float  aspect = float(std::abs(bounds.size.width / bounds.size.height));

    // Set the new aspect ratio for the mvp linear transformation matrix

    mpVisualizer.aspect = aspect;

} // _update

- (void) mtkView:(nonnull MTKView *)view drawableSizeWillChange:(CGSize)size

{

    // Update the mvp linear transformation matrix

    [self _update:view];

} // mtkView

- (void) drawInMTKView:(nonnull MTKView *)view

{

    if(view)

    {

        @autoreleasepool

        {

            [self _update:view];

            // Draw the particles from the N-body simulation

            mpVisualizer.drawable = view.currentDrawable;

        }

    } // if

} // drawInMTKView

- (void) didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

} // didReceiveMemoryWarning

- (UIStatusBarStyle) preferredStatusBarStyle

{

    return UIStatusBarStyleLightContent;

} // preferredStatusBarStyle

- (void) viewDidAppear:(BOOL)animated

{

    [super viewDidAppear:animated];

    // Instantiate a new N-body visualizer object

    mpVisualizer = [NBodyVisualizer new];

    assert(mpVisualizer);

    // Acquire all the resources for the visualizer object

    mpVisualizer.device = device;

    // If successful in acquiring resources for the visualizer

    // object, then continue

    assert(mpVisualizer.haveVisualizer);

} // viewDidAppear

- (void) viewDidLoad

{

    [super viewDidLoad];

    // Acquire a default Metal system device

    device = MTLCreateSystemDefaultDevice();

    // If this is a valid system device, then continue

    assert(device);

    // Our view should be a Metal-Kit view

    mpView = static_cast<MTKView *>(self.view);

    // If this a valid Metal-kit view, then continue

    assert(mpView);

    // Metal-kit view requires a Metal device and an app delegate

    mpView.device   = device;

    mpView.delegate = self;

} // viewDidLoad

@end