Fix cached GL context on all platforms (#737)

4 files changed, 13 insertions, 14 deletions

diff --git a/src/Fl_Gl_Window_Driver.H b/src/Fl_Gl_Window_Driver.H
index ee3332545..d40cbf89e 100644
--- a/src/Fl_Gl_Window_Driver.H
+++ b/src/Fl_Gl_Window_Driver.H
@@ -38,7 +38,6 @@ protected:
   GLint current_prog;
   Fl_Gl_Window *pWindow;
 public:
-  static GLContext cached_context;
   static Fl_Window* cached_window;
   static int nContext;
   static GLContext *context_list;
diff --git a/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
index b821ae201..5241f2375 100644
--- a/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
@@ -228,8 +228,8 @@ void Fl_Wayland_Gl_Window_Driver::set_gl_context(Fl_Window* w, GLContext context
     target_egl_surface = dr->gl_start_support_->egl_surface = eglCreateWindowSurface(
         egl_display, wld_egl_conf, dr->gl_start_support_->egl_window, NULL);
   }
-  if (context != cached_context || w != cached_window) {
-    cached_context = context;
+  GLContext current_context = eglGetCurrentContext();
+  if (context != current_context || w != cached_window) {
     cached_window = w;
     if (eglMakeCurrent(egl_display, target_egl_surface, target_egl_surface,
                        (EGLContext)context)) {
@@ -259,11 +259,11 @@ void Fl_Wayland_Gl_Window_Driver::apply_scissor() {
 
 
 void Fl_Wayland_Gl_Window_Driver::delete_gl_context(GLContext context) {
-  if (cached_context == context) {
-    cached_context = 0;
+  GLContext current_context = eglGetCurrentContext();
+  if (current_context == context) {
     cached_window = 0;
   }
-  if (eglGetCurrentContext() == (EGLContext)context) {
+  if (current_context == (EGLContext)context) {
     eglMakeCurrent(egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
   }
   eglDestroyContext(egl_display, (EGLContext)context);
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Gl_Window_Driver.cxx b/src/drivers/WinAPI/Fl_WinAPI_Gl_Window_Driver.cxx
index 0c94f8af5..d6f1a9632 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Gl_Window_Driver.cxx
+++ b/src/drivers/WinAPI/Fl_WinAPI_Gl_Window_Driver.cxx
@@ -163,16 +163,16 @@ GLContext Fl_WinAPI_Gl_Window_Driver::create_gl_context(Fl_Window* window, const
 }
 
 void Fl_WinAPI_Gl_Window_Driver::set_gl_context(Fl_Window* w, GLContext context) {
-  if (context != cached_context || w != cached_window) {
-    cached_context = context;
+  GLContext current_context = wglGetCurrentContext();
+  if (context != current_context || w != cached_window) {
     cached_window = w;
     wglMakeCurrent(Fl_WinAPI_Window_Driver::driver(w)->private_dc, (HGLRC)context);
   }
 }
 
 void Fl_WinAPI_Gl_Window_Driver::delete_gl_context(GLContext context) {
-  if (cached_context == context) {
-    cached_context = 0;
+  GLContext current_context = wglGetCurrentContext();
+  if (current_context == context) {
     cached_window = 0;
     wglMakeCurrent(0, 0);
   }
diff --git a/src/drivers/X11/Fl_X11_Gl_Window_Driver.cxx b/src/drivers/X11/Fl_X11_Gl_Window_Driver.cxx
index 985978c1f..83bf28333 100644
--- a/src/drivers/X11/Fl_X11_Gl_Window_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Gl_Window_Driver.cxx
@@ -321,16 +321,16 @@ GLContext Fl_X11_Gl_Window_Driver::create_gl_context(XVisualInfo *vis) {
 }*/
 
 void Fl_X11_Gl_Window_Driver::set_gl_context(Fl_Window* w, GLContext context) {
-  if (context != cached_context || w != cached_window) {
-    cached_context = context;
+  GLContext current_context = glXGetCurrentContext();
+  if (context != current_context || w != cached_window) {
     cached_window = w;
     glXMakeCurrent(fl_display, fl_xid(w), (GLXContext)context);
   }
 }
 
 void Fl_X11_Gl_Window_Driver::delete_gl_context(GLContext context) {
-  if (cached_context == context) {
-    cached_context = 0;
+  GLContext current_context = glXGetCurrentContext();
+  if (current_context == context) {
     cached_window = 0;
     glXMakeCurrent(fl_display, 0, 0);
   }