Handmade Hero-like Mac OS X setup and gfx code

hamahe.m

// Bare bones Handmade Hero-like functionality (but not in HH coding style)
// Simple graphics, runloop and initialization only, needs a XIB for the menubar etc.
// Compiles as normal Objective-C
// (c) 2014 by @zenmumbler

#import <Cocoa/Cocoa.h>
#import <CoreGraphics/CoreGraphics.h>
#include <stdint.h>

static bool running = false;
static int xOffset;

// capture all the app objects so ARC won't deallocate them immediately
@class HHView;
@class HHAppDelegate;
@class HHWindowDelegate;

static HHAppDelegate *appDelegate;
static NSWindow *mainWindow;
static HHView *mainView;
static HHWindowDelegate *winDelegate;


@interface HHAppDelegate : NSObject<NSApplicationDelegate> {
}
@property (nonatomic, strong) NSArray* xibObjects;
@end
@implementation HHAppDelegate
- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication *)sender {
    // Cocoa will kill your app on the spot if you don't stop it
    // So if you want to do anything beyond your main loop then include this method.
    running = false;
    return NSTerminateCancel;
}
@end


@interface HHWindowDelegate : NSObject<NSWindowDelegate> {}
@end
@implementation HHWindowDelegate
- (BOOL)windowShouldClose:(id)sender {
    running = false;
    return NO;
}
@end


@interface HHView : NSView {
    void* dataPtr_;
    CGContextRef backBuffer_;
}
- (instancetype)initWithFrame:(NSRect)frameRect;
- (void)drawRect:(NSRect)dirtyRect;
- (void*)bitmapData;
@end
@implementation HHView

- (instancetype)initWithFrame:(NSRect)frameRect {
    self = [super initWithFrame: frameRect];
    if (self) {
        int width = frameRect.size.width;
        int height = frameRect.size.height;
        int rowBytes = 4 * width;
        dataPtr_ = calloc(1, rowBytes * height); // calloc clears memory upon first touch
        
        CMProfileRef prof; // these 2 calls are deprecated as of 10.6, but still work and I can't find their modern equivalent.
        CMGetSystemProfile(&prof);
        CGColorSpaceRef colorSpace = CGColorSpaceCreateWithPlatformColorSpace(prof);
        
        backBuffer_ = CGBitmapContextCreate(dataPtr_, width, height, 8, rowBytes, colorSpace, kCGImageAlphaNoneSkipLast | kCGBitmapByteOrderDefault);
        CGColorSpaceRelease(colorSpace);
        CMCloseProfile(prof);
    }
    return self;
}

- (void*)bitmapData {
    return dataPtr_;
}

- (void)drawRect:(NSRect)dirtyRect {
    CGContextRef ctx = [[NSGraphicsContext currentContext] CGContext];
    CGImageRef backImage = CGBitmapContextCreateImage(backBuffer_);
    CGContextDrawImage(ctx, self.frame, backImage);
    CGImageRelease(backImage);
}
@end


static void createWindow() {
    NSRect frame = NSMakeRect(0, 0, (CGFloat)1024, (CGFloat)768);
    
    mainWindow = [[NSWindow alloc]
                  initWithContentRect: frame
                  styleMask: NSTitledWindowMask | NSClosableWindowMask
                  backing: NSBackingStoreBuffered
                  defer: NO
                  ];
    [mainWindow setTitle: @"Handmade Hero"];
    [mainWindow setAcceptsMouseMovedEvents: YES];
    [mainWindow setOpaque: YES];
    [mainWindow center];
    
    mainView = [[HHView alloc] initWithFrame:frame];
    [mainWindow setContentView: mainView];

    winDelegate = [[HHWindowDelegate alloc] init];
    [mainWindow setDelegate: winDelegate];

    [mainWindow makeKeyAndOrderFront: nil];
}


void initApp() {
    NSApplication* app = [NSApplication sharedApplication];
    
    appDelegate = [[HHAppDelegate alloc] init];
    [app setDelegate: appDelegate];
    
    // -- install menubar, etc.; store top-level objects in the app delegate to retain them
    NSArray *tlo;
    [[NSBundle mainBundle] loadNibNamed:@"MainMenu" owner:appDelegate topLevelObjects: &tlo];
    appDelegate.xibObjects = tlo;
    
    // -- allow relative paths to work from the Contents/Resources directory
    // -- this would be different if running without a bundle
    const char *resourcePath = [[[NSBundle mainBundle] resourcePath] UTF8String];
    chdir(resourcePath);
    
    running = true;
    [app finishLaunching];
}

void frame() {
    @autoreleasepool {
        NSEvent* ev;
        do {
            ev = [NSApp nextEventMatchingMask: NSAnyEventMask
                                    untilDate: nil
                                       inMode: NSDefaultRunLoopMode
                                      dequeue: YES];
            if (ev) {
                // handle events here
                [NSApp sendEvent: ev];
            }
        } while (ev);
    }
}

void renderStuff() {
    uint32_t *bitmap = (uint32_t*)([mainView bitmapData]);
    int width = [mainView frame].size.width,
        height = [mainView frame].size.height;
    
    for (int y=0; y < height; ++y) {
        for (int x=0; x < width; ++x) {
            uint8_t blue = x + xOffset;
            uint8_t green = y;
            // note different bitshifts from main HH code as on OS X byte order is RR GG BB AA
            *bitmap++ = ((green << 16) | blue << 8);
        }
    }
}

int main(int argc, const char * argv[]) {
    initApp();
    createWindow();
    
    while (running) {
        frame();
        renderStuff();
        [mainView setNeedsDisplay:YES];
        ++xOffset;
    }
}