app/internal/wm: [macOS] use NSView+NSOpenGLContext, not NSOpenGLContextView

NSOpenGLContextView couples the window manager logic tightly with
OpenGL. Use generic NSViews, and attach NSOpenGLContext just like the
other platforms.

This change prepares for supporting GPU contexts created by clients as
well as a future Metal port.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/internal/wm/gl_macos.go

@@ -5,6 +5,8 @@
 package wm
 
 import (
+	"errors"
+
 	"gioui.org/gpu"
 	"gioui.org/internal/gl"
 )
@@ -15,8 +17,9 @@ import (
 #include <AppKit/AppKit.h>
 #include <OpenGL/gl3.h>
 
-__attribute__ ((visibility ("hidden"))) CFTypeRef gio_createGLView(void);
-__attribute__ ((visibility ("hidden"))) CFTypeRef gio_contextForView(CFTypeRef viewRef);
+__attribute__ ((visibility ("hidden"))) CFTypeRef gio_createGLContext(void);
+__attribute__ ((visibility ("hidden"))) void gio_prepareContext(void);
+__attribute__ ((visibility ("hidden"))) void gio_setContextView(CFTypeRef ctx, CFTypeRef view);
 __attribute__ ((visibility ("hidden"))) void gio_makeCurrentContext(CFTypeRef ctx);
 __attribute__ ((visibility ("hidden"))) void gio_flushContextBuffer(CFTypeRef ctx);
 __attribute__ ((visibility ("hidden"))) void gio_clearCurrentContext(void);
@@ -26,20 +29,23 @@ __attribute__ ((visibility ("hidden"))) void gio_unlockContext(CFTypeRef ctxRef)
 import "C"
 
 type context struct {
-	c    *gl.Functions
-	ctx  C.CFTypeRef
-	view C.CFTypeRef
-}
-
-func init() {
-	viewFactory = func() C.CFTypeRef {
-		return C.gio_createGLView()
-	}
+	c        *gl.Functions
+	ctx      C.CFTypeRef
+	view     C.CFTypeRef
+	prepared bool
 }
 
 func newContext(w *window) (*context, error) {
 	view := w.contextView()
-	ctx := C.gio_contextForView(view)
+	ctx := C.gio_createGLContext()
+	if ctx == 0 {
+		return nil, errors.New("gl: failed to create NSOpenGLContext")
+	}
+	// [NSOpenGLContext setView] must run on the main thread. Fortunately,
+	// newContext is only called during a [NSView draw] on the main thread.
+	w.w.Func(func() {
+		C.gio_setContextView(ctx, view)
+	})
 	c := &context{
 		ctx:  ctx,
 		view: view,
@@ -52,14 +58,9 @@ func (c *context) API() gpu.API {
 }
 
 func (c *context) Release() {
-	c.Lock()
-	defer c.Unlock()
 	C.gio_clearCurrentContext()
-	// We could release the context with [view clearGLContext]
-	// and rely on [view openGLContext] auto-creating a new context.
-	// However that second context is not properly set up by
-	// OpenGLContextView, so we'll stay on the safe side and keep
-	// the first context around.
+	C.CFRelease(c.ctx)
+	c.ctx = 0
 }
 
 func (c *context) Present() error {
@@ -80,6 +81,10 @@ func (c *context) MakeCurrent() error {
 	c.Lock()
 	defer c.Unlock()
 	C.gio_makeCurrentContext(c.ctx)
+	if !c.prepared {
+		c.prepared = true
+		C.gio_prepareContext()
+	}
 	return nil
 }
 

app/internal/wm/gl_macos.m

@@ -9,91 +9,21 @@
 #include <OpenGL/gl3.h>
 #include "_cgo_export.h"
 
-static void handleMouse(NSView *view, NSEvent *event, int typ, CGFloat dx, CGFloat dy) {
-	NSPoint p = [view convertPoint:[event locationInWindow] fromView:nil];
-	if (!event.hasPreciseScrollingDeltas) {
-		// dx and dy are in rows and columns.
-		dx *= 10;
-		dy *= 10;
-	}
-	gio_onMouse((__bridge CFTypeRef)view, typ, [NSEvent pressedMouseButtons], p.x, p.y, dx, dy, [event timestamp], [event modifierFlags]);
-}
-
-@interface GioView : NSOpenGLView 
+@interface GioGLContext : NSOpenGLContext
 @end
 
-@implementation GioView
-- (instancetype)initWithFrame:(NSRect)frameRect
-				  pixelFormat:(NSOpenGLPixelFormat *)format {
-	return [super initWithFrame:frameRect pixelFormat:format];
+@implementation GioGLContext
+- (void) notifyUpdate:(NSNotification*)notification {
+	CGLLockContext([self CGLContextObj]);
+	[self update];
+	CGLUnlockContext([self CGLContextObj]);
 }
-- (void)prepareOpenGL {
-	[super prepareOpenGL];
-	// Bind a default VBA to emulate OpenGL ES 2.
-	GLuint defVBA;
-	glGenVertexArrays(1, &defVBA);
-	glBindVertexArray(defVBA);
-	glEnable(GL_FRAMEBUFFER_SRGB);
-}
-- (BOOL)isFlipped {
-	return YES;
-}
-- (void)update {
-	[super update];
-	[self setNeedsDisplay:YES];
-}
-- (void)drawRect:(NSRect)r {
-	gio_onDraw((__bridge CFTypeRef)self);
-}
-- (void)mouseDown:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_DOWN, 0, 0);
-}
-- (void)mouseUp:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_UP, 0, 0);
-}
-- (void)middleMouseDown:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_DOWN, 0, 0);
-}
-- (void)middletMouseUp:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_UP, 0, 0);
-}
-- (void)rightMouseDown:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_DOWN, 0, 0);
-}
-- (void)rightMouseUp:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_UP, 0, 0);
-}
-- (void)mouseMoved:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_MOVE, 0, 0);
-}
-- (void)mouseDragged:(NSEvent *)event {
-	handleMouse(self, event, GIO_MOUSE_MOVE, 0, 0);
-}
-- (void)scrollWheel:(NSEvent *)event {
-	CGFloat dx = -event.scrollingDeltaX;
-	CGFloat dy = -event.scrollingDeltaY;
-	handleMouse(self, event, GIO_MOUSE_SCROLL, dx, dy);
-}
-- (void)keyDown:(NSEvent *)event {
-	NSString *keys = [event charactersIgnoringModifiers];
-	gio_onKeys((__bridge CFTypeRef)self, (char *)[keys UTF8String], [event timestamp], [event modifierFlags], true);
-	[self interpretKeyEvents:[NSArray arrayWithObject:event]];
-}
-- (void)keyUp:(NSEvent *)event {
-	NSString *keys = [event charactersIgnoringModifiers];
-	gio_onKeys((__bridge CFTypeRef)self, (char *)[keys UTF8String], [event timestamp], [event modifierFlags], false);
-}
-- (void)insertText:(id)string {
-	const char *utf8 = [string UTF8String];
-	gio_onText((__bridge CFTypeRef)self, (char *)utf8);
-}
-- (void)doCommandBySelector:(SEL)sel {
-	// Don't pass commands up the responder chain.
-	// They will end up in a beep.
+- (void)dealloc {
+	[[NSNotificationCenter defaultCenter] removeObserver:self];
 }
 @end
 
-CFTypeRef gio_createGLView(void) {
+CFTypeRef gio_createGLContext(void) {
 	@autoreleasepool {
 		NSOpenGLPixelFormatAttribute attr[] = {
 			NSOpenGLPFAOpenGLProfile, NSOpenGLProfileVersion3_2Core,
@@ -105,43 +35,54 @@ CFTypeRef gio_createGLView(void) {
 			NSOpenGLPFAAllowOfflineRenderers,
 			0
 		};
-		id pixFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attr];
+		NSOpenGLPixelFormat *pixFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attr];
 
-		NSRect frame = NSMakeRect(0, 0, 0, 0);
-		GioView* view = [[GioView alloc] initWithFrame:frame pixelFormat:pixFormat];
-
-		[view setWantsBestResolutionOpenGLSurface:YES];
-		[view setWantsLayer:YES]; // The default in Mojave.
-
-		return CFBridgingRetain(view);
+		GioGLContext *ctx = [[GioGLContext alloc] initWithFormat:pixFormat shareContext: nil];
+		return CFBridgingRetain(ctx);
 	}
 }
 
-void gio_setNeedsDisplay(CFTypeRef viewRef) {
-	NSOpenGLView *view = (__bridge NSOpenGLView *)viewRef;
-	[view setNeedsDisplay:YES];
-}
-
-CFTypeRef gio_contextForView(CFTypeRef viewRef) {
-	NSOpenGLView *view = (__bridge NSOpenGLView *)viewRef;
-	return (__bridge CFTypeRef)view.openGLContext;
+void gio_setContextView(CFTypeRef ctxRef, CFTypeRef viewRef) {
+	GioGLContext *ctx = (__bridge GioGLContext *)ctxRef;
+	NSView *view = (__bridge NSView *)viewRef;
+	[ctx setView:view];
+	[[NSNotificationCenter defaultCenter] addObserver:ctx
+											 selector:@selector(notifyUpdate:)
+												 name:NSViewGlobalFrameDidChangeNotification
+											   object:view];
 }
 
 void gio_clearCurrentContext(void) {
-	[NSOpenGLContext clearCurrentContext];
+	@autoreleasepool {
+		[NSOpenGLContext clearCurrentContext];
+	}
 }
 
 void gio_makeCurrentContext(CFTypeRef ctxRef) {
-	NSOpenGLContext *ctx = (__bridge NSOpenGLContext *)ctxRef;
-	[ctx makeCurrentContext];
+	@autoreleasepool {
+		NSOpenGLContext *ctx = (__bridge NSOpenGLContext *)ctxRef;
+		[ctx makeCurrentContext];
+	}
 }
 
 void gio_lockContext(CFTypeRef ctxRef) {
-	NSOpenGLContext *ctx = (__bridge NSOpenGLContext *)ctxRef;
-	CGLLockContext([ctx CGLContextObj]);
+	@autoreleasepool {
+		NSOpenGLContext *ctx = (__bridge NSOpenGLContext *)ctxRef;
+		CGLLockContext([ctx CGLContextObj]);
+	}
 }
 
 void gio_unlockContext(CFTypeRef ctxRef) {
-	NSOpenGLContext *ctx = (__bridge NSOpenGLContext *)ctxRef;
-	CGLUnlockContext([ctx CGLContextObj]);
+	@autoreleasepool {
+		NSOpenGLContext *ctx = (__bridge NSOpenGLContext *)ctxRef;
+		CGLUnlockContext([ctx CGLContextObj]);
+	}
+}
+
+void gio_prepareContext(void) {
+	// Bind a default VBA to emulate OpenGL ES 2.
+	GLuint defVBA;
+	glGenVertexArrays(1, &defVBA);
+	glBindVertexArray(defVBA);
+	glEnable(GL_FRAMEBUFFER_SRGB);
 }

app/internal/wm/os_macos.go

@@ -42,6 +42,7 @@ __attribute__ ((visibility ("hidden"))) CFTypeRef gio_readClipboard(void);
 __attribute__ ((visibility ("hidden"))) void gio_writeClipboard(unichar *chars, NSUInteger length);
 __attribute__ ((visibility ("hidden"))) void gio_setNeedsDisplay(CFTypeRef viewRef);
 __attribute__ ((visibility ("hidden"))) void gio_toggleFullScreen(CFTypeRef windowRef);
+__attribute__ ((visibility ("hidden"))) CFTypeRef gio_createView(void);
 __attribute__ ((visibility ("hidden"))) CFTypeRef gio_createWindow(CFTypeRef viewRef, const char *title, CGFloat width, CGFloat height, CGFloat minWidth, CGFloat minHeight, CGFloat maxWidth, CGFloat maxHeight);
 __attribute__ ((visibility ("hidden"))) void gio_makeKeyAndOrderFront(CFTypeRef windowRef);
 __attribute__ ((visibility ("hidden"))) NSPoint gio_cascadeTopLeftFromPoint(CFTypeRef windowRef, NSPoint topLeft);
@@ -73,8 +74,6 @@ type window struct {
 // viewMap is the mapping from Cocoa NSViews to Go windows.
 var viewMap = make(map[C.CFTypeRef]*window)
 
-var viewFactory func() C.CFTypeRef
-
 // launched is closed when applicationDidFinishLaunching is called.
 var launched = make(chan struct{})
 
@@ -401,7 +400,7 @@ func NewWindow(win Callbacks, opts *Options) error {
 }
 
 func newWindow(opts *Options) (*window, error) {
-	view := viewFactory()
+	view := C.gio_createView()
 	if view == 0 {
 		return nil, errors.New("CreateWindow: failed to create view")
 	}

app/internal/wm/os_macos.m

@@ -42,6 +42,73 @@
 }
 @end
 
+static void handleMouse(NSView *view, NSEvent *event, int typ, CGFloat dx, CGFloat dy) {
+	NSPoint p = [view convertPoint:[event locationInWindow] fromView:nil];
+	if (!event.hasPreciseScrollingDeltas) {
+		// dx and dy are in rows and columns.
+		dx *= 10;
+		dy *= 10;
+	}
+	gio_onMouse((__bridge CFTypeRef)view, typ, [NSEvent pressedMouseButtons], p.x, p.y, dx, dy, [event timestamp], [event modifierFlags]);
+}
+
+@interface GioView : NSView
+@end
+
+@implementation GioView
+- (BOOL)isFlipped {
+	return YES;
+}
+- (void)drawRect:(NSRect)r {
+	gio_onDraw((__bridge CFTypeRef)self);
+}
+- (void)mouseDown:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_DOWN, 0, 0);
+}
+- (void)mouseUp:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_UP, 0, 0);
+}
+- (void)middleMouseDown:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_DOWN, 0, 0);
+}
+- (void)middletMouseUp:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_UP, 0, 0);
+}
+- (void)rightMouseDown:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_DOWN, 0, 0);
+}
+- (void)rightMouseUp:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_UP, 0, 0);
+}
+- (void)mouseMoved:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_MOVE, 0, 0);
+}
+- (void)mouseDragged:(NSEvent *)event {
+	handleMouse(self, event, GIO_MOUSE_MOVE, 0, 0);
+}
+- (void)scrollWheel:(NSEvent *)event {
+	CGFloat dx = -event.scrollingDeltaX;
+	CGFloat dy = -event.scrollingDeltaY;
+	handleMouse(self, event, GIO_MOUSE_SCROLL, dx, dy);
+}
+- (void)keyDown:(NSEvent *)event {
+	NSString *keys = [event charactersIgnoringModifiers];
+	gio_onKeys((__bridge CFTypeRef)self, (char *)[keys UTF8String], [event timestamp], [event modifierFlags], true);
+	[self interpretKeyEvents:[NSArray arrayWithObject:event]];
+}
+- (void)keyUp:(NSEvent *)event {
+	NSString *keys = [event charactersIgnoringModifiers];
+	gio_onKeys((__bridge CFTypeRef)self, (char *)[keys UTF8String], [event timestamp], [event modifierFlags], false);
+}
+- (void)insertText:(id)string {
+	const char *utf8 = [string UTF8String];
+	gio_onText((__bridge CFTypeRef)self, (char *)utf8);
+}
+- (void)doCommandBySelector:(SEL)sel {
+	// Don't pass commands up the responder chain.
+	// They will end up in a beep.
+}
+@end
 // Delegates are weakly referenced from their peers. Nothing
 // else holds a strong reference to our window delegate, so
 // keep a single global reference instead.
@@ -86,6 +153,11 @@ CGFloat gio_getViewBackingScale(CFTypeRef viewRef) {
 	return [view.window backingScaleFactor];
 }
 
+void gio_setNeedsDisplay(CFTypeRef viewRef) {
+	NSView *view = (__bridge NSView *)viewRef;
+	[view setNeedsDisplay:YES];
+}
+
 void gio_hideCursor() {
 	@autoreleasepool {
 		[NSCursor hide];
@@ -229,6 +301,16 @@ void gio_setTitle(CFTypeRef windowRef, const char *title) {
   window.title = [NSString stringWithUTF8String: title];
 }
 
+CFTypeRef gio_createView(void) {
+	@autoreleasepool {
+		NSRect frame = NSMakeRect(0, 0, 0, 0);
+		GioView* view = [[GioView alloc] initWithFrame:frame];
+		[view setWantsBestResolutionOpenGLSurface:YES];
+		[view setWantsLayer:YES]; // The default in Mojave.
+		return CFBridgingRetain(view);
+	}
+}
+
 @implementation GioAppDelegate
 - (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
 	[[NSRunningApplication currentApplication] activateWithOptions:(NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)];

app/internal/wm/window.go

@@ -55,6 +55,10 @@ type FrameEvent struct {
 type Callbacks interface {
 	SetDriver(d Driver)
 	Event(e event.Event)
+	// Func runs a function during an Event. This is required for platforms
+	// that require coordination between the rendering goroutine and the system
+	// main thread.
+	Func(f func())
 }
 
 type Context interface {

app/window.go

@@ -56,7 +56,8 @@ type Window struct {
 }
 
 type callbacks struct {
-	w *Window
+	w     *Window
+	funcs chan func()
 }
 
 // queue is an event.Queue implementation that distributes system events
@@ -104,6 +105,7 @@ func NewWindow(options ...Option) *Window {
 		driverFuncs: make(chan func()),
 		dead:        make(chan struct{}),
 	}
+	w.callbacks.funcs = make(chan func())
 	w.callbacks.w = w
 	go w.run(opts)
 	return w
@@ -299,11 +301,22 @@ func (c *callbacks) SetDriver(d wm.Driver) {
 func (c *callbacks) Event(e event.Event) {
 	select {
 	case c.w.in <- e:
-		<-c.w.ack
+		for {
+			select {
+			case <-c.w.ack:
+				return
+			case f := <-c.funcs:
+				f()
+			}
+		}
 	case <-c.w.dead:
 	}
 }
 
+func (c *callbacks) Func(f func()) {
+	c.funcs <- f
+}
+
 func (w *Window) waitAck() {
 	// Send a dummy event; when it gets through we
 	// know the application has processed the previous event.