From cace309838b9edaae66e1e8ddfbf60d8c6cf6f23 Mon Sep 17 00:00:00 2001
From: Albrecht Schlosser <albrechts.fltk@online.de>
Date: Mon, 20 Dec 2010 14:48:38 +0000
Subject: [PATCH] Fixed OpenGL overlay drawing (STR #2437). Back-ported the
 corresponding patch for FLTK 1.3.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.1@8077 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 CHANGES              |  1 +
 src/Fl_Gl_Window.cxx | 14 +++++++++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/CHANGES b/CHANGES
index e69fa23fa..a6303bfb9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,6 @@
 CHANGES IN FLTK 1.1.11
 
+	- Fixed OpenGL overlay drawing (STR #2437)
 	- Fixed Fl_Tabs selection border drawing, if tabs are at the bottom
 	  of the widget (part of STR #2480)
 	- Documentation fixes (STR #2410)
diff --git a/src/Fl_Gl_Window.cxx b/src/Fl_Gl_Window.cxx
index 6a39b0990..588a03196 100644
--- a/src/Fl_Gl_Window.cxx
+++ b/src/Fl_Gl_Window.cxx
@@ -285,10 +285,7 @@ void Fl_Gl_Window::flush() {
     glDrawBuffer(GL_BACK);
 
     if (!SWAP_TYPE) {
-#ifdef __APPLE_QD__
-      SWAP_TYPE = COPY;
-#elif defined __APPLE_QUARTZ__
-      // warning: the Quartz version should probably use Core GL (CGL) instead of AGL
+#if !defined(WIN32) // __APPLE__ || X11
       SWAP_TYPE = COPY;
 #else
       SWAP_TYPE = UNDEFINED;
@@ -298,6 +295,7 @@ void Fl_Gl_Window::flush() {
 	if (!strcmp(c,"COPY")) SWAP_TYPE = COPY;
 	else if (!strcmp(c, "NODAMAGE")) SWAP_TYPE = NODAMAGE;
 	else if (!strcmp(c, "SWAP")) SWAP_TYPE = SWAP;
+	else SWAP_TYPE = UNDEFINED;
       }
     }
 
@@ -314,6 +312,12 @@ void Fl_Gl_Window::flush() {
       if (damage() != FL_DAMAGE_OVERLAY || !save_valid) draw();
       swap_buffers();
 
+    } else if (SWAP_TYPE == SWAP) {
+      damage(FL_DAMAGE_ALL);
+      draw();
+      if (overlay == this) draw_overlay();
+      swap_buffers();
+
     } else { // SWAP_TYPE == UNDEFINED
 
       // If we are faking the overlay, use CopyPixels to act like
@@ -350,7 +354,7 @@ void Fl_Gl_Window::flush() {
 
     }
 
-    if (overlay==this) { // fake overlay in front buffer
+    if (overlay==this && SWAP_TYPE != SWAP) { // fake overlay in front buffer
       glDrawBuffer(GL_FRONT);
       draw_overlay();
       glDrawBuffer(GL_BACK);