commit c2efb0d8494b101d9700afc79302fcf371995a6e
Author:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
AuthorDate: Wed Sep 28 17:06:00 2022 +0200
Commit:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
CommitDate: Wed Sep 28 17:06:00 2022 +0200

    macOS: support of FLTK widgets in OpenGL 3 windows - cont'd.
    This code is OK under macOS 10 9 and 13.

 examples/OpenGL3test.cxx                        |  6 +++--
 src/Fl_cocoa.mm                                 | 16 +++++++-----
 src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.H   |  3 ++-
 src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.cxx | 34 ++++++++++++++++++++-----
 src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H      |  5 +++-
 5 files changed, 48 insertions(+), 16 deletions(-)

diff --git examples/OpenGL3test.cxx examples/OpenGL3test.cxx
index edcb56d..40d0bf7 100644
--- examples/OpenGL3test.cxx
+++ examples/OpenGL3test.cxx
@@ -191,8 +191,10 @@ void toggle_double(Fl_Widget *wid, void *data) {
   SimpleGL3Window *glwin = (SimpleGL3Window*)data;
   int flags = glwin->mode();
   if (doublebuff) flags |= FL_DOUBLE; else flags &= ~FL_DOUBLE;
-  glwin->mode(flags);
   glwin->reset();
+  glwin->hide();
+  glwin->mode(flags);
+  glwin->show();
 }
 
 
@@ -227,7 +229,7 @@ void button_cb(Fl_Widget *, void *) {
 }
 
 void add_widgets(Fl_Gl_Window *g) {
-  Fl::set_color(FL_FREE_COLOR, 255, 0, 0, 140); // partially transparent red
+  Fl::set_color(FL_FREE_COLOR, 255, 255, 255, 140); // partially transparent white
   g->begin();
   // Create here widgets to go above the GL3 scene
   Fl_Button* b = new Fl_Button( 0, 170, 60, 30, "button");
diff --git src/Fl_cocoa.mm src/Fl_cocoa.mm
index 9cb302d..ccb4ebe 100644
--- src/Fl_cocoa.mm
+++ src/Fl_cocoa.mm
@@ -2941,25 +2941,29 @@ NSOpenGLContext* Fl_Cocoa_Window_Driver::create_GLcontext_for_window(NSOpenGLPix
 }
 
 
-NSOpenGLContext *Fl_Cocoa_Window_Driver::gl1ctxt_create() {
+NSOpenGLContext *Fl_Cocoa_Window_Driver::gl1ctxt_create(NSView **gl1view) {
   FLView *view = (FLView*)[fl_xid(pWindow) contentView];
-  NSView *gl1view = [[NSView alloc] initWithFrame:[view frame]];
-  [view addSubview:gl1view];
-  [gl1view release];
+  *gl1view = [[NSView alloc] initWithFrame:[view frame]];
   NSOpenGLPixelFormat *gl1pixelformat =
       Fl_Cocoa_Window_Driver::mode_to_NSOpenGLPixelFormat(
                               FL_RGB8 | FL_ALPHA | FL_SINGLE, NULL);
   NSOpenGLContext *gl1ctxt = [[NSOpenGLContext alloc]
                               initWithFormat:gl1pixelformat shareContext:nil];
   [gl1pixelformat release];
-  remove_gl_context_opacity(gl1ctxt);
+  return gl1ctxt;
+}
+
+void Fl_Cocoa_Window_Driver::gl1ctxt_add(NSOpenGLContext *gl1ctxt, NSView *gl1view) {
+  FLView *flview = (FLView*)[fl_xid(pWindow) contentView];
+  [flview addSubview:gl1view];
+  [gl1view release];
 #if MAC_OS_X_VERSION_MAX_ALLOWED > MAC_OS_X_VERSION_10_7
   if (fl_mac_os_version >= 100700 && Fl::use_high_res_GL()) {
     [gl1view setWantsBestResolutionOpenGLSurface:YES];
   }
 #endif
   [gl1ctxt setView:gl1view];
-  return gl1ctxt;
+  remove_gl_context_opacity(gl1ctxt);
 }
 
 
diff --git src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.H src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.H
index e1a8dab..f0456ee 100644
--- src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.H
+++ src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.H
@@ -28,9 +28,9 @@ class Fl_Gl_Choice;
 
 class Fl_Cocoa_Gl_Window_Driver : public Fl_Gl_Window_Driver {
   NSOpenGLContext *gl1ctxt; // GL1 context in addition to GL3 context
+  static void delayed_addgl1ctxt(void *data);
   friend Fl_Gl_Window_Driver* Fl_Gl_Window_Driver::newGlWindowDriver(Fl_Gl_Window *);
   Fl_Cocoa_Gl_Window_Driver(Fl_Gl_Window *win);
-  ~Fl_Cocoa_Gl_Window_Driver();
   virtual float pixels_per_unit();
   virtual void before_show(int& need_after);
   virtual void after_show();
@@ -53,6 +53,7 @@ class Fl_Cocoa_Gl_Window_Driver : public Fl_Gl_Window_Driver {
   void apply_scissor();
   virtual void switch_to_GL1();
   virtual void switch_back();
+  virtual void gl_hide_before(void *&);
 };
 
 
diff --git src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.cxx src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.cxx
index 7a20a75..bb4c53d 100644
--- src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.cxx
+++ src/drivers/Cocoa/Fl_Cocoa_Gl_Window_Driver.cxx
@@ -53,10 +53,6 @@ Fl_Cocoa_Gl_Window_Driver::Fl_Cocoa_Gl_Window_Driver(Fl_Gl_Window *win) :
   gl1ctxt = NULL;
 }
 
-Fl_Cocoa_Gl_Window_Driver::~Fl_Cocoa_Gl_Window_Driver() {
-  if (gl1ctxt) Fl_Cocoa_Window_Driver::GLcontext_release(gl1ctxt);
-}
-
 Fl_Gl_Choice *Fl_Cocoa_Gl_Window_Driver::find(int m, const int *alistp)
 {
   Fl::screen_driver()->open_display(); // useful when called through gl_start()
@@ -331,12 +327,31 @@ FL_EXPORT NSOpenGLContext *fl_mac_glcontext(GLContext rc) {
  view/GL context.
  */
 
+static struct win_view {
+  Fl_Gl_Window *win;
+  NSView *gl1view;
+  NSOpenGLContext *gl1ctxt;
+} win_view_struct;
+
+void Fl_Cocoa_Gl_Window_Driver::delayed_addgl1ctxt(void *d) {
+  struct win_view *data = (struct win_view *)d;
+  Fl_Cocoa_Window_Driver::driver(data->win)->gl1ctxt_add(data->gl1ctxt, data->gl1view);
+  data->win->redraw();
+}
+
 void Fl_Cocoa_Gl_Window_Driver::switch_to_GL1() {
   if (!gl1ctxt) {
-    gl1ctxt = Fl_Cocoa_Window_Driver::driver(pWindow)->gl1ctxt_create();
-    Fl::add_timeout(0.01, (Fl_Timeout_Handler)delayed_redraw, pWindow);
+    gl1ctxt = Fl_Cocoa_Window_Driver::driver(pWindow)->gl1ctxt_create(
+                &win_view_struct.gl1view);
+    win_view_struct.win = pWindow;
+    win_view_struct.gl1ctxt = gl1ctxt;
+    Fl::add_timeout(0.01,
+            Fl_Cocoa_Gl_Window_Driver::delayed_addgl1ctxt,
+            &win_view_struct);
   }
   Fl_Cocoa_Window_Driver::GLcontext_makecurrent(gl1ctxt);
+  glClearColor(0., 0., 0., 0.);
+  glClear(GL_COLOR_BUFFER_BIT);
 }
 
 void Fl_Cocoa_Gl_Window_Driver::switch_back() {
@@ -344,6 +359,13 @@ void Fl_Cocoa_Gl_Window_Driver::switch_back() {
   Fl_Cocoa_Window_Driver::GLcontext_makecurrent((NSOpenGLContext*)pWindow->context());
 }
 
+void Fl_Cocoa_Gl_Window_Driver::gl_hide_before(void *&) {
+  if (gl1ctxt) {
+  	Fl_Cocoa_Window_Driver::GLcontext_release(gl1ctxt);
+    gl1ctxt = 0;
+  }
+}
+
 
 class Fl_Gl_Cocoa_Plugin : public Fl_Cocoa_Plugin {
 public:
diff --git src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H
index d6f7534..16cea4e 100644
--- src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H
+++ src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H
@@ -36,6 +36,7 @@ class Fl_Window;
 @class FLWindow;
 @class NSOpenGLContext;
 @class NSOpenGLPixelFormat;
+@class NSView;
 #else
 class CALayer;
 class NSCursor;
@@ -43,6 +44,7 @@ class NSImage;
 class FLWindow;
 class NSOpenGLContext;
 class NSOpenGLPixelFormat;
+class NSView;
 #endif // __OBJC__
 
 /**
@@ -155,7 +157,8 @@ public:
   static void GL_cleardrawable(void); // uses Objective-c
   static void gl_start(NSOpenGLContext*); // uses Objective-c
   static void remove_gl_context_opacity(NSOpenGLContext*); // uses Objective-c
-  NSOpenGLContext *gl1ctxt_create(); // uses Objective-c
+  NSOpenGLContext *gl1ctxt_create(NSView **); // uses Objective-c
+  void gl1ctxt_add(NSOpenGLContext*, NSView*); // uses Objective-c
   static void gl1ctxt_resize(NSOpenGLContext*); // uses Objective-c
 
   //icons