Only in OpenCSG-1.3.1-fbo-patch/: lib
diff -ur OpenCSG-1.3.1/src/frameBufferObject.cpp OpenCSG-1.3.1-fbo-patch/src/frameBufferObject.cpp
--- OpenCSG-1.3.1/src/frameBufferObject.cpp	2010-06-09 14:39:58.000000000 -0500
+++ OpenCSG-1.3.1-fbo-patch/src/frameBufferObject.cpp	2011-11-23 21:42:42.709641637 -0600
@@ -3,8 +3,8 @@
 //
 // This library is free software; you can redistribute it and/or 
 // modify it under the terms of the GNU General Public License, 
-// Version 2, as published by the Free Software Foundation.
-// As a special exception, you have permission to link this library
+// Version 2, as published by the Free Software Foundation.
+// As a special exception, you have permission to link this library
 // with the CGAL library and distribute executables.
 //
 // This library is distributed in the hope that it will be useful, 
@@ -59,6 +59,7 @@
             glGenRenderbuffers(1, &depthID); 
             glGenTextures(1, &textureID);
 
+            glGetIntegerv(GL_FRAMEBUFFER_BINDING, &oldFramebufferID);
             glBindFramebuffer(GL_FRAMEBUFFER, framebufferID);
             glBindTexture(GL_TEXTURE_2D, textureID);
             glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_INT, 0);
@@ -78,7 +79,7 @@
                 return false;
             }
 
-            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            glBindFramebuffer(GL_FRAMEBUFFER, oldFramebufferID);
             glBindTexture(GL_TEXTURE_2D, 0);
 
             textureTarget = GL_TEXTURE_2D;
Only in OpenCSG-1.3.1-fbo-patch/src: frameBufferObject.cpp~
diff -ur OpenCSG-1.3.1/src/frameBufferObjectExt.cpp OpenCSG-1.3.1-fbo-patch/src/frameBufferObjectExt.cpp
--- OpenCSG-1.3.1/src/frameBufferObjectExt.cpp	2010-06-09 14:39:58.000000000 -0500
+++ OpenCSG-1.3.1-fbo-patch/src/frameBufferObjectExt.cpp	2011-11-23 21:07:00.073641732 -0600
@@ -3,8 +3,8 @@
 //
 // This library is free software; you can redistribute it and/or 
 // modify it under the terms of the GNU General Public License, 
-// Version 2, as published by the Free Software Foundation.
-// As a special exception, you have permission to link this library
+// Version 2, as published by the Free Software Foundation.
+// As a special exception, you have permission to link this library
 // with the CGAL library and distribute executables.
 //
 // This library is distributed in the hope that it will be useful, 
@@ -60,6 +60,7 @@
             glGenRenderbuffersEXT(1, &depthID); 
             glGenTextures(1, &textureID);
 
+            glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &oldFramebufferID);
             glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID);	
             glBindTexture(GL_TEXTURE_2D, textureID);
             glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_INT, 0);
@@ -79,7 +80,7 @@
                 return false;
             }
 
-            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, oldFramebufferID);
             glBindTexture(GL_TEXTURE_2D, 0);
 
             textureTarget = GL_TEXTURE_2D;
@@ -136,7 +137,7 @@
         // Unbinds frame buffer texture.
         bool FrameBufferObjectExt::EndCapture()
         {
-            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, oldFramebufferID);
             return true;
         }
 
diff -ur OpenCSG-1.3.1/src/frameBufferObjectExt.h OpenCSG-1.3.1-fbo-patch/src/frameBufferObjectExt.h
--- OpenCSG-1.3.1/src/frameBufferObjectExt.h	2010-06-09 14:39:58.000000000 -0500
+++ OpenCSG-1.3.1-fbo-patch/src/frameBufferObjectExt.h	2011-11-23 21:07:15.529642039 -0600
@@ -3,8 +3,8 @@
 //
 // This library is free software; you can redistribute it and/or 
 // modify it under the terms of the GNU General Public License, 
-// Version 2, as published by the Free Software Foundation.
-// As a special exception, you have permission to link this library
+// Version 2, as published by the Free Software Foundation.
+// As a special exception, you have permission to link this library
 // with the CGAL library and distribute executables.
 //
 // This library is distributed in the hope that it will be useful, 
@@ -85,6 +85,7 @@
             unsigned int depthID;
 
             unsigned int framebufferID;
+            int oldFramebufferID;
 
             bool         initialized;
         };
diff -ur OpenCSG-1.3.1/src/frameBufferObject.h OpenCSG-1.3.1-fbo-patch/src/frameBufferObject.h
--- OpenCSG-1.3.1/src/frameBufferObject.h	2010-06-09 14:39:58.000000000 -0500
+++ OpenCSG-1.3.1-fbo-patch/src/frameBufferObject.h	2011-11-23 21:37:07.565641308 -0600
@@ -3,8 +3,8 @@
 //
 // This library is free software; you can redistribute it and/or 
 // modify it under the terms of the GNU General Public License, 
-// Version 2, as published by the Free Software Foundation.
-// As a special exception, you have permission to link this library
+// Version 2, as published by the Free Software Foundation. 
+// As a special exception, you have permission to link this library 
 // with the CGAL library and distribute executables.
 //
 // This library is distributed in the hope that it will be useful, 
@@ -85,6 +85,7 @@
             unsigned int depthID;
 
             unsigned int framebufferID;
+            int oldFramebufferID;
 
             bool         initialized;
         };