NSView in OS 10.11 El Capitan Throwing Errors - opengl

Question

I have an OpenGL application I'm running in Xcode 7.0.1 on a 2011 MacBookPro.
I recently upgraded from OS 10.10 to 10.11 El Capitan, and now windows with NSViews are throwing this error (Deployment Target 10.11, 10.10 or 10.9):
invalid context 0x0. If you want to see the backtrace, please set
CG_CONTEXT_SHOW_BACKTRACE environmental variable.
In the NSView drawRect method, I get the CGContext with the following statement:
CGContextRef context = [[NSGraphicsContext currentContext] CGContext];
Also, my GLSL 4.1 shaders don't write anything to the OpenGL window anymore.
This code was not giving me any problems before I upgraded to El Capitan, and the (almost) exact same code runs fine without errors on a 2012 MacBookPro, OS 10.10, Xcode 6.4, Deployment Target 10.9 or 10.10. The only code difference is that the graphics context in the NSView drawRect method is obtained with:
CGContextRef context = [[NSGraphicsContext currentContext] graphicsPort];
I think my problem might be that the computer that has problems is a 2011 MacBookPro, and Metal requires 2012 or later. I'm not using Metal, but I still think this might be a factor.
Is the computer vintage the problem that generates the error, or is there some other syntax I should be using to get the graphics context?
I have no idea why the GLSL shaders don't work anymore. Any ideas there?
The application main window is an OpenGL view, but I use many NSViews in pop up user interface windows, custom buttons and various other uses. Below is the complete code for one of the simplest of those windows. Again, this all ran fine before I upgraded to EC and Xcode 7.0.1.
#implementation StatusView
// **************************** Init **********************************
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
}
return self;
}
// ************************** Draw Rect ********************************
- (void)drawRect:(NSRect)dirtyRect
{
if(windowManager)
{
CGContextRef context = [[NSGraphicsContext currentContext] CGContext];
// Define a color space variable
CGColorSpaceRef rgbColorspace = CGColorSpaceCreateDeviceRGB();
// Get the bounds
NSRect nsBounds = [self bounds];
// Set the graphics bounds
CGRect cgBounds = NSRectToCGRect(nsBounds);
// ****** Draw the Background in Transparent Black
CGContextSetRGBFillColor(context, 0.0f, 0.0f, 0.0f, 0.0f);
CGContextFillRect(context, cgBounds);
// Set the text matrix.
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
// Create a color that will be added as an attribute to the attrString for normal text.
CGFloat textColorComponents[] = { 1.0, 1.0, 1.0, 1.0 };
CGColorRef whiteColor = CGColorCreate(rgbColorspace, textColorComponents);
// Create a color that will be added as an attribute to the attrString for invisible text.
CGFloat invisibleTextColorComponents[] = { 0.0, 0.0, 0.0, 0.0 };
CGColorRef invisibleColor = CGColorCreate(rgbColorspace, invisibleTextColorComponents);
// Create a font for normal text.
CFStringRef stringFontName = CFSTR("AppleCasual");
CTFontRef stringFont = CTFontCreateWithName(stringFontName, 18.0, NULL);
CGContextSetRGBFillColor(context, 0.0f, 0.0f, 0.0f, 0.0f);
CGContextFillRect(context, cgBounds);
// ************* Box the Window in Gray ***************************
CGContextMoveToPoint(context, 0.0,1.0);
CGContextAddLineToPoint(context,0.0, cgBounds.size.height - 1.0);
CGContextAddLineToPoint(context,cgBounds.size.width - 2.0, cgBounds.size.height - 1.0);
CGContextAddLineToPoint(context,cgBounds.size.width - 2.0, 1.0);
CGContextAddLineToPoint(context,0.0, 1.0);
CGContextSetLineWidth(context, 2.0);
CGContextSetRGBStrokeColor(context, 0.7, 0.7, 0.7, 1.0);
CGContextStrokePath(context);
// *********** Draw String1
CGPoint endingTextPoint;
if(windowManager->statusTextBox1String)
{
// Create a mutable attributed string with a max length of 0 for normal text.
CFMutableAttributedStringRef attrString = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
// Create a path which will bound the area where you will be drawing text.
CGMutablePathRef invisibleTextPath = CGPathCreateMutable();
// Create a path which will bound the area where you will be drawing text.
CGMutablePathRef string1TextPath = CGPathCreateMutable();
// Initialize a string.
CFStringRef textString = (__bridge CFStringRef)windowManager->statusTextBox1String;
CFIndex textStringLength = CFStringGetLength (textString);
// Measure the string length
CGRect invisibleTextBounds = CGRectMake(0.0, 0.0, cgBounds.size.width, 30.0);
CGPathAddRect(invisibleTextPath, NULL, invisibleTextBounds);
// Copy the textString into attrString
CFAttributedStringReplaceString (attrString, CFRangeMake(0, 0), textString);
// Set the color and font.
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTForegroundColorAttributeName, invisibleColor);
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTFontAttributeName, stringFont);
// Create the framesetter with the attributed string.
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrString);
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), invisibleTextPath, NULL);
// Draw the specified frame in the given context.
CTFrameDraw(frame, context);
endingTextPoint = CGContextGetTextPosition(context);
// Draw the Text
// Set a rectangular path.
CGRect textBounds = CGRectMake((cgBounds.size.width / 2.0) - (endingTextPoint.x / 2.0), 140.0, cgBounds.size.width, 30.0);
CGPathAddRect(string1TextPath, NULL, textBounds);
// Copy the textString into attrString
CFAttributedStringReplaceString (attrString, CFRangeMake(0, textStringLength), textString);
// Set the color and fontof the first chars.
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTForegroundColorAttributeName, whiteColor);
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTFontAttributeName, stringFont);
// Create the framesetter with the attributed string.
framesetter = CTFramesetterCreateWithAttributedString(attrString);
// Create a frame.
frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), string1TextPath, NULL);
// Draw the specified frame in the given context.
CTFrameDraw(frame, context);
CFRelease(string1TextPath);
CFRelease(invisibleTextPath);
CFRelease(frame);
CFRelease(framesetter);
CFRelease(attrString);
}
// ****************** Draw String 2
if(windowManager->statusTextBox2String)
{
CGContextSetRGBFillColor(context, 0.0f, 0.0f, 0.0f, 0.0f);
CGContextFillRect(context, cgBounds);
// ********** Box the Window in Gray ***********************
CGContextMoveToPoint(context, 0.0,1.0);
CGContextAddLineToPoint(context,0.0, cgBounds.size.height - 1.0);
CGContextAddLineToPoint(context,cgBounds.size.width - 2.0, cgBounds.size.height - 1.0);
CGContextAddLineToPoint(context,cgBounds.size.width - 2.0, 1.0);
CGContextAddLineToPoint(context,0.0, 1.0);
CGContextSetLineWidth(context, 2.0);
CGContextSetRGBStrokeColor(context, 0.7, 0.7, 0.7, 1.0);
CGContextStrokePath(context);
// Create a mutable attributed string with a max length of 0 for normal text.
CFMutableAttributedStringRef attrString = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
// Create a path which will bound the area where you will be drawing text.
CGMutablePathRef invisibleTextPath = CGPathCreateMutable();
// Create a path which will bound the area where you will be drawing text.
CGMutablePathRef string2TextPath = CGPathCreateMutable();
// Initialize a string.
CFStringRef textString = (__bridge CFStringRef)windowManager->statusTextBox2String;
CFIndex textStringLength = CFStringGetLength (textString);
// Measure the string length
CGRect invisibleTextBounds = CGRectMake(0.0, 0.0, cgBounds.size.width, 130.0);
CGPathAddRect(invisibleTextPath, NULL, invisibleTextBounds);
// Copy the textString into attrString
CFAttributedStringReplaceString (attrString, CFRangeMake(0, 0), textString);
// Set the color and font
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTForegroundColorAttributeName, invisibleColor);
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTFontAttributeName, stringFont);
// Create the framesetter with the attributed string.
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrString);
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), invisibleTextPath, NULL);
// Draw the specified frame in the given context.
CTFrameDraw(frame, context);
endingTextPoint = CGContextGetTextPosition(context);
// Draw the Text
// Set a rectangular path.
CGRect textBounds = CGRectMake((cgBounds.size.width / 2.0) - (endingTextPoint.x / 2.0), 100.0, cgBounds.size.width, 30.0);
CGPathAddRect(string2TextPath, NULL, textBounds);
// Copy the textString into attrString
CFAttributedStringReplaceString (attrString, CFRangeMake(0, textStringLength), textString);
// Set the color and fontof the first chars.
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTForegroundColorAttributeName, whiteColor);
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, textStringLength), kCTFontAttributeName, stringFont);
// Create the framesetter with the attributed string.
framesetter = CTFramesetterCreateWithAttributedString(attrString);
// Create a frame.
frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), string2TextPath, NULL);
// Draw the specified frame in the given context.
CTFrameDraw(frame, context);
CFRelease(string2TextPath);
CFRelease(invisibleTextPath);
CFRelease(frame);
CFRelease(framesetter);
CFRelease(attrString);
}
CFRelease(stringFont);
CFRelease(whiteColor);
CFRelease(invisibleColor);
CGContextFlush(context);
}
return;
}
#end
This is an image of what this particular window looks like:
The behavior is not consistent. For example, this status window should come up for each of several steps in the calculation process, but it looks like only every other window is displayed (e.g. steps 2, 4 and 6, but not 1, 3 or 5).
There are LOTS of errors being generated, but this is a sample backtrace from one of the errors:
Oct 9 10:23:30 WispFractals3D[746] <Error>: CGContextRestoreGState: invalid context 0x0. Backtrace:
<-[StatusWindowController updateStatusProgress:]+228>
<-[AppController updateStatusProgress:]+64>
<-[AppController runTheFractal:]+804>
<_os_activity_initiate+75>
<-[NSApplication sendAction:to:from:]+460>
<-[NSMenuItem _corePerformAction]+336>
<-[NSCarbonMenuImpl performActionWithHighlightingForItemAtIndex:]+114>
<_os_activity_initiate+75>
<-[NSMenu performActionForItemAtIndex:]+131>
<-[NSMenu _internalPerformActionForItemAtIndex:]+35>
<-[NSCarbonMenuImpl _carbonCommandProcessEvent:handlerCallRef:]+107>
<NSSLMMenuEventHandler+708>
<_ZL23DispatchEventToHandlersP14EventTargetRecP14OpaqueEventRefP14HandlerCallRec+1231>
<_ZL30SendEventToEventTargetInternalP14OpaqueEventRefP20OpaqueEventTargetRefP14HandlerCallRec+404>
<SendEventToEventTarget+40>
<_ZL18SendHICommandEventjPK9HICommandjjhPKvP20OpaqueEventTargetRefS5_PP14OpaqueEventRef+411>
<SendMenuCommandWithContextAndModifiers+59>
<SendMenuItemSelectedEvent+188>
<_ZL19FinishMenuSelectionP13SelectionDataP10MenuResultS2_+96>
<_ZL14MenuSelectCoreP8MenuData5PointdjPP13OpaqueMenuRefPt+711>
<_HandleMenuSelection2+460>
<_NSHandleCarbonMenuEvent+277>
<_DPSNextEvent+1906>
<-[NSApplication _nextEventMatchingEventMask:untilDate:inMode:dequeue:]+454>
<-[NSApplication run]+682>
<NSApplicationMain+1176>
<main+34>
The .xib file looks like this:
There's a custom progress indicator in this window (bounded by the two white squares) that's invisible, but it's there.
Sample code to display this window looks like:
[self showStatusWindowWithString1:#"Calculation Complete" String2:timeMessage ButtonOn:YES AbortOn:NO ProgressOn:NO ProgressMax:100.0 Title:#"Fractal Run Time"];
and the code for the showStatusWindow method is:
- (void)showStatusWindowWithString1:(NSString *)string1 String2:(NSString *)string2 ButtonOn:(BOOL)buttonon AbortOn:(BOOL)aborton ProgressOn:(BOOL)progresson ProgressMax:(double)progressmax Title:(NSString *)title
{
statusWindowTitle = title;
statusTextBox1String = string1;
statusTextBox2String = string2;
statusButtonOn = buttonon;
abortOn = aborton;
statusProgressOn = progresson;
statusProgressMax = progressmax;
if (!statusWindowController)
{
statusWindowController = [[StatusWindowController alloc] initWithWindowNibName:#"StatusWindow" Manager:self];
}
[[statusWindowController window] setTitle:statusWindowTitle];
[statusWindowController showWindow:self];
[fileStatusWindow makeKeyAndOrderFront:self];
appDelegate->fileStatusWindowOpenFlag = YES;
[appDelegate checkFlags];
return;
}
Ken Thomases diagnosed that the backtrace indicated that invalid context errors were being generated in [StatusWindowController updateStatusProgress:] (this updates a custom progress indicator).
I changed this method from:
- (void) updateStatusProgress:(double)statusprogress
{
[statusProgressIndicator setDoubleValue:statusprogress];
[statusProgressIndicator drawRect:[statusProgressIndicator bounds]];
}
To:
- (void) updateStatusProgress:(double)statusprogress
{
[statusProgressIndicator setDoubleValue:statusprogress];
[statusProgressIndicator setNeedsDisplay:YES];
}
It looked to me like the error messages were being generated in multiple places, but this one change stopped all error messages.
My next problem, was that the status window (image above) was not displaying every time it should, only sometimes. Again, this all worked fine in Yosemite, Xcode 6.4.
I've now found that when the status window does not display, I can get it to display by running it modally. Strange.
The last problem I'm working through is that the GLSL shaders are not writing to the OpenGL view as they should. I've tested that the shaders are loading and running by adding a line at the end of the fragment shader: fragColor = vec4(1.0, 0.0, 0.0, 1.0);, which turned the view totally red as it should.
The fragment shader actually should be sampling from a texture, so I loaded this texture with all (255, 0, 0, 255) to test the sampling by putting a simple sampling statement at the end of the fragment shader:
fragColor = texture(Texture, texCoord).rgba;
but nothing gets written, so there must be a problem with loading the texture into the shader. I'm working on that now.

Answer 1

The problem causing the "invalid context 0x0" messages was that you were directly calling -drawRect:. This has never been valid. -drawRect: is called by the framework after it has set up the appropriate graphics context and things like the coordinate transform to put the drawing in the right place in the window and clipping to the bounds of the view. If you call it at other times, then no context has been set up and nothing good can come of it.
If you must redraw immediately, you could call one of the -display... methods.
However, it's usually best to do as you've now done: simply mark the view as needing display and let Cocoa redraw it in due course.
You should probably post separate questions for the other issues.

Answer 2

I just did a quick build of one of my apps which hadn't been rebuilt under EC before. It all worked fine.
Perhaps you can post a bit more detail. The code and crash point?