CLK/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m

//
//  CSOpenGLView
//  CLK
//
//  Created by Thomas Harte on 16/07/2015.
//  Copyright 2015 Thomas Harte. All rights reserved.
//

#import "CSOpenGLView.h"
@import CoreVideo;
@import GLKit;

@interface CSOpenGLView () <NSDraggingDestination>
@end

@implementation CSOpenGLView {
	CVDisplayLinkRef _displayLink;
	CGSize _backingSize;

	NSTrackingArea *_mouseTrackingArea;
	NSTimer *_mouseHideTimer;
}

- (void)prepareOpenGL {
	// Synchronize buffer swaps with vertical refresh rate
	GLint swapInt = 1;
	[[self openGLContext] setValues:&swapInt forParameter:NSOpenGLCPSwapInterval];

	// Create a display link capable of being used with all active displays
	CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink);

	// Set the renderer output callback function
	CVDisplayLinkSetOutputCallback(_displayLink, DisplayLinkCallback, (__bridge void * __nullable)(self));

	// Set the display link for the current renderer
	CGLContextObj cglContext = [[self openGLContext] CGLContextObj];
	CGLPixelFormatObj cglPixelFormat = [[self pixelFormat] CGLPixelFormatObj];
	CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(_displayLink, cglContext, cglPixelFormat);

	// set the clear colour
	[self.openGLContext makeCurrentContext];
	glClearColor(0.0, 0.0, 0.0, 1.0);

	// Activate the display link
	CVDisplayLinkStart(_displayLink);
}

static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp *now, const CVTimeStamp *outputTime, CVOptionFlags flagsIn, CVOptionFlags *flagsOut, void *displayLinkContext) {
	CSOpenGLView *const view = (__bridge CSOpenGLView *)displayLinkContext;
	[view drawAtTime:now frequency:CVDisplayLinkGetActualOutputVideoRefreshPeriod(displayLink)];
	return kCVReturnSuccess;
}

- (void)drawAtTime:(const CVTimeStamp *)now frequency:(double)frequency {
	[self redrawWithEvent:CSOpenGLViewRedrawEventTimer];
}

- (void)drawRect:(NSRect)dirtyRect {
	[self redrawWithEvent:CSOpenGLViewRedrawEventAppKit];
}

- (void)redrawWithEvent:(CSOpenGLViewRedrawEvent)event {
	[self performWithGLContext:^{
		[self.delegate openGLViewRedraw:self event:event];
		CGLFlushDrawable([[self openGLContext] CGLContextObj]);
	}];
}

- (void)invalidate {
	CVDisplayLinkStop(_displayLink);
}

- (void)dealloc {
	// Release the display link
	CVDisplayLinkRelease(_displayLink);
}

- (CGSize)backingSize {
	@synchronized(self) {
		return _backingSize;
	}
}

- (void)reshape {
	[super reshape];
	@synchronized(self) {
		_backingSize = [self convertSizeToBacking:self.bounds.size];
	}

	[self performWithGLContext:^{
		CGSize viewSize = [self backingSize];
		glViewport(0, 0, (GLsizei)viewSize.width, (GLsizei)viewSize.height);
	}];
}

- (void)awakeFromNib {
	NSOpenGLPixelFormatAttribute attributes[] = {
		NSOpenGLPFADoubleBuffer,
		NSOpenGLPFAOpenGLProfile,	NSOpenGLProfileVersion3_2Core,
//		NSOpenGLPFAMultisample,
//		NSOpenGLPFASampleBuffers,	1,
//		NSOpenGLPFASamples,			2,
		0
	};

	NSOpenGLPixelFormat *pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attributes];
	NSOpenGLContext *context = [[NSOpenGLContext alloc] initWithFormat:pixelFormat shareContext:nil];

#ifdef DEBUG
	// When we're using a CoreProfile context, crash if we call a legacy OpenGL function
	// This will make it much more obvious where and when such a function call is made so
	// that we can remove such calls.
	// Without this we'd simply get GL_INVALID_OPERATION error for calling legacy functions
	// but it would be more difficult to see where that function was called.
	CGLEnable([context CGLContextObj], kCGLCECrashOnRemovedFunctions);
#endif

	self.pixelFormat = pixelFormat;
	self.openGLContext = context;
	self.wantsBestResolutionOpenGLSurface = YES;

	// Register to receive dragged and dropped file URLs.
	[self registerForDraggedTypes:@[(__bridge NSString *)kUTTypeFileURL]];
}

- (void)performWithGLContext:(dispatch_block_t)action {
	CGLLockContext([[self openGLContext] CGLContextObj]);
	[self.openGLContext makeCurrentContext];
	action();
	CGLUnlockContext([[self openGLContext] CGLContextObj]);
}

#pragma mark - NSResponder

- (BOOL)acceptsFirstResponder {
	return YES;
}

- (void)keyDown:(NSEvent *)theEvent {
	[self.responderDelegate keyDown:theEvent];
}

- (void)keyUp:(NSEvent *)theEvent {
	[self.responderDelegate keyUp:theEvent];
}

- (void)flagsChanged:(NSEvent *)theEvent {
	[self.responderDelegate flagsChanged:theEvent];
}

- (void)paste:(id)sender {
	[self.responderDelegate paste:sender];
}

#pragma mark - NSDraggingDestination

- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
	for(NSPasteboardItem *item in [[sender draggingPasteboard] pasteboardItems]) {
		NSURL *URL = [NSURL URLWithString:[item stringForType:(__bridge NSString *)kUTTypeFileURL]];
		[self.delegate openGLView:self didReceiveFileAtURL:URL];
	}
	return YES;
}

- (NSDragOperation)draggingEntered:(id < NSDraggingInfo >)sender {
	return NSDragOperationLink;
}

#pragma mark - Mouse hiding

- (void)updateTrackingAreas {
	[super updateTrackingAreas];

	if(_mouseTrackingArea) {
		[self removeTrackingArea:_mouseTrackingArea];
	}
	_mouseTrackingArea =
		[[NSTrackingArea alloc]
			initWithRect:self.bounds
			options:NSTrackingMouseEnteredAndExited | NSTrackingMouseMoved | NSTrackingActiveWhenFirstResponder
			owner:self
			userInfo:nil];
	[self addTrackingArea:_mouseTrackingArea];
}

- (void)mouseMoved:(NSEvent *)event {
	[super mouseMoved:event];
	[self scheduleMouseHide];
}

- (void)mouseEntered:(NSEvent *)event {
	[super mouseEntered:event];
	[self scheduleMouseHide];
}

- (void)scheduleMouseHide {
	[_mouseHideTimer invalidate];
	_mouseHideTimer = [NSTimer scheduledTimerWithTimeInterval:3.0 repeats:NO block:^(NSTimer * _Nonnull timer) {
        [NSCursor setHiddenUntilMouseMoves:YES];
	}];
}

- (void)mouseExited:(NSEvent *)event {
	[super mouseExited:event];

	[_mouseHideTimer invalidate];
	_mouseHideTimer = nil;
}

@end