From 9550d745cdcf4a819b4563338385d8626810ecb1 Mon Sep 17 00:00:00 2001
From: Matthias Melcher <fltk@matthiasm.com>
Date: Wed, 20 Jan 2016 22:24:08 +0000
Subject: Avoid clipping stack overruns in OpenGL graphics driver

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11018 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/Fl_Gl_Window.cxx | 10 ++++++++++
 src/fl_rect.cxx      |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/Fl_Gl_Window.cxx b/src/Fl_Gl_Window.cxx
index e74065ac6..82b38fd14 100644
--- a/src/Fl_Gl_Window.cxx
+++ b/src/Fl_Gl_Window.cxx
@@ -187,6 +187,8 @@ public:
   }
   void push_clip(int x, int y, int w, int h) {
     // TODO: implement OpenGL clipping
+    if (rstackptr < region_stack_max) rstack[++rstackptr] = 0L;
+    else Fl::warning("Fl_OpenGL_Graphics_Driver::push_clip: clip stack overflow!\n");
   }
   int clip_box(int x, int y, int w, int h, int &X, int &Y, int &W, int &H) {
     // TODO: implement OpenGL clipping
@@ -199,12 +201,20 @@ public:
   }
   void push_no_clip() {
     // TODO: implement OpenGL clipping
+    if (rstackptr < region_stack_max) rstack[++rstackptr] = 0;
+    else Fl::warning("Fl_OpenGL_Graphics_Driver::push_no_clip: clip stack overflow!\n");
+    restore_clip();
   }
   void pop_clip() {
     // TODO: implement OpenGL clipping
+    if (rstackptr > 0) {
+      rstackptr--;
+    } else Fl::warning("Fl_OpenGL_Graphics_Driver::pop_clip: clip stack underflow!\n");
+    restore_clip();
   }
   void restore_clip() {
     // TODO: implement OpenGL clipping
+    fl_clip_state_number++;
   }
 };
 
diff --git a/src/fl_rect.cxx b/src/fl_rect.cxx
index 7979c1085..771cc6a8b 100644
--- a/src/fl_rect.cxx
+++ b/src/fl_rect.cxx
@@ -45,9 +45,9 @@
 // This is defined in src/fl_line_style.cxx
 extern int fl_line_width_;
 
+
 void Fl_Graphics_Driver::restore_clip() {
   fl_clip_state_number++;
-  Fl_Region r = rstack[rstackptr];
 }
 
 void Fl_Graphics_Driver::clip_region(Fl_Region r) {
-- 
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