Minimal self container OpenGL Example on OSX

gltest.m

//
// Minimal self container OpenGL Example
//
// Compile with:
// xcrun gcc -o test -framework Foundation -framework OpenGL -framework CoreGraphics -framework AppKit main.m
//

#import <Foundation/Foundation.h>
#import <CoreGraphics/CoreGraphics.h>
#import <OpenGL/OpenGL.h>
#import <OpenGL/gl.h>
#import <Carbon/Carbon.h>
#import <CoreFoundation/CoreFoundation.h>
#import <AppKit/AppKit.h>

#include <math.h>

@class MyWindow;

@interface MyRunner : NSObject
@property (nonatomic, readwrite) float time;
@property (nonatomic, readwrite) NSOpenGLContext *ctx;
@property (nonatomic, readwrite) MyWindow *window;
- (id)init;
- (void)doTick: (NSTimer*)timer;
@end

@interface MyWindow : NSWindow
@property (nonatomic, readwrite) MyRunner *runner;
@end

@implementation MyWindow

#define KEY_F 3
#define KEY_ESCAPE 53
#define KEY_RETURN 36
#define KEY_TAB 48
#define KEY_SPACE 49
#define KEY_Q 12

- (void) postCreate {
    [self setLevel:NSMainMenuWindowLevel+1];
    [self setOpaque:YES];
    [self makeKeyAndOrderFront:nil];
    
    CGLEnable((CGLContextObj)[self.runner.ctx CGLContextObj], kCGLCEMPEngine);
    [self.runner.ctx setView:self.contentView];
    [self.runner.ctx makeCurrentContext];
}

- (void) keyDown: (NSEvent*)ev {
    if ([ev isARepeat])
        return;
    
    NSLog(@"key down: %d", [ev keyCode]);

    if ([ev keyCode] == KEY_F || [ev keyCode] == KEY_RETURN) {
        //
        // Toggle fullscreen with 'F' or Return
        //
        
        if (self.styleMask & NSTitledWindowMask) {
            NSLog(@"Go fullscreen...");
            [self setStyleMask: NSFullScreenWindowMask ];
            [self makeKeyAndOrderFront:nil];
        
            NSRect viewRect = NSMakeRect(0.0, 0.0, self.screen.frame.size.width, self.screen.frame.size.height);

            [self setFrame:viewRect display:YES];
            [self.contentView setFrame:viewRect];
            
            [self.runner.ctx setView:self.contentView];
            [self.runner.ctx update];

        } else {
            NSLog(@"Go windowed...");
            [self setStyleMask: NSTitledWindowMask | NSResizableWindowMask | NSClosableWindowMask ];
            NSRect viewRect = NSMakeRect(0.0, 0.0, 800, 600);

            [self setFrame:viewRect display:YES];
            [self.contentView setFrame:viewRect];
            [self.runner.ctx setView:self.contentView];
            
            [self makeKeyAndOrderFront:nil];
            [self center];
            [self.runner.ctx update];
        }
    }
    
    if ([ev keyCode] == KEY_ESCAPE || [ev keyCode] == KEY_Q) {
        //
        // quit with 'Q' or Escape
        //
        
        [NSApp stop:nil];
        [NSApp postEvent: [NSEvent otherEventWithType:NSApplicationDefined location:NSZeroPoint modifierFlags:0 timestamp:0.0 windowNumber:0 context:NULL subtype:0 data1:0 data2:0] atStart:NO];
    }
    
    if ([ev keyCode] == KEY_SPACE) {
        self.runner.time = (float) (rand() % 10000);
    }
}

@end

@implementation MyRunner

- (id) init {
    self = [super init];
    self.time = .0f;
    
    NSOpenGLPixelFormatAttribute attrs[] = {
        NSOpenGLPFADoubleBuffer,
        NSOpenGLPFAScreenMask,
        (NSOpenGLPixelFormatAttribute)CGDisplayIDToOpenGLDisplayMask(CGMainDisplayID()),
        NSOpenGLPFADepthSize,
        (NSOpenGLPixelFormatAttribute)16,
        (NSOpenGLPixelFormatAttribute)0
    };
    
    NSOpenGLPixelFormat *fmt = [[NSOpenGLPixelFormat alloc] initWithAttributes: attrs];
    
    self.ctx = [[NSOpenGLContext alloc] initWithFormat: fmt shareContext: nil];
    
    NSRect viewRect = NSMakeRect(0, 0, 800, 600);
    
    unsigned style = NSTitledWindowMask | NSMiniaturizableWindowMask | NSClosableWindowMask;
    self.window = [[MyWindow alloc] initWithContentRect: viewRect styleMask:style backing:NSBackingStoreBuffered defer:YES];
    self.window.runner = self;
    [self.window postCreate];
    [self.window center];
    
    ProcessSerialNumber psn = { 0, kCurrentProcess };
    TransformProcessType(&psn, kProcessTransformToForegroundApplication);

    [NSTimer scheduledTimerWithTimeInterval: 1.0f / 60.0f target:self selector: @selector(doTick:) userInfo: nil repeats: YES];
    
    return self;
}

- (void) doTick: (NSTimer*)timer {
    float T = self.time;
    self.time += 1.0 / 60.0f;
    
    GLint value = 1;
    [self.ctx setValues: &value
      forParameter: NSOpenGLCPSwapInterval];
    
    NSRect viewRect = ((NSView *)self.window.contentView).frame;
    
    glViewport(0,0, viewRect.size.width,viewRect.size.height);
    glClearColor(0.1f + 0.1f * sin(T * 2.0f), 0.1f + 0.1f * sin(T * 3.0f), 0.1f, 1.0f);
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
    
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    
    glBegin(GL_LINES);

    glColor3f(0.1, 0.1, 0.1);
    
    glVertex3f(-1,-1,0);
    glVertex3f(1,1,0);
    glVertex3f(1,-1,0);
    glVertex3f(-1,1,0);
    
    for(int k=0; k<30; k++) {
        float z = (float)(k - 10 + fmod(T, 1.0)) / 10.0f;

        glVertex3f(-1,z,0);
        glVertex3f(1,z,0);
        glVertex3f(z,-1,0);
        glVertex3f(z,1,0);
    }

    for(int k=0; k<100; k++) {
        float z = (float)k / 100.0;
        glColor3f(z,z,z);
        
        float x, y;
        float T2 = T + (float)k / 100.0;
        float C1 = T / 333.0;
        float C2 = T / 100.0 + (float)k / 430.0;

        x = sin(T2 * 3.1 + C2) * cos(T2 * 2.4 + C1);
        y = cos(T2 * 3.9 + C2) * sin(T2 * 2.2 + C2);
        glVertex3f(x,y,0);
        
        x = sin(T2 * 3.7 + C1) * cos(T2 * 1.3 + C2);
        y = cos(T2 * 3.6 + C1) * sin(T2 * 1.1 + C2);
        glVertex3f(x,y,0);
    }
    
    glEnd();
    
    [self.ctx flushBuffer];
}

@end

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        [NSApplication sharedApplication];
        [MyRunner new];
        [NSApp run];
    }
    return 0;
}