From 1aa0a80de7f0afeb044098637216a80752e4ab07 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Tue, 24 Apr 2018 16:22:13 +0100
Subject: [PATCH] Added OSG_GL_CONTEXT_STRING cmake variable to set
 include/osg/GL headers that sets Traits::glContextVersion.

---
 CMakeLists.txt              | 4 ++++
 src/osg/DisplaySettings.cpp | 2 +-
 src/osg/GL.in               | 1 +
 src/osg/GraphicsContext.cpp | 2 +-
 4 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f3006fa5c..91718422c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -556,9 +556,13 @@ ELSE()
     OPTION(OSG_CPP_EXCEPTIONS_AVAILABLE "Set to OFF to disable compile of OSG components that use C++ exceptions." ON)
 ENDIF()
 
+SET(OSG_GL_CONTEXT_STRING "1.0" CACHE STRING "GL Context String to pass when creaing graphics contexts")
 
 # Map the OSG_GL*_AVAILABLE settings to OpenGL header settings
 IF (OSG_GL3_AVAILABLE)
+
+    SET(OSG_GL_CONTEXT_STRING "3.3")
+
     IF (APPLE)
         SET(OPENGL_HEADER1 "#include <OpenGL/gl.h>" CACHE STRING "#include<> line for OpenGL Header")
         SET(OPENGL_HEADER2 "#include <OpenGL/gl3.h>" CACHE STRING "#include<> line for additional OpenGL Headers if required")
diff --git a/src/osg/DisplaySettings.cpp b/src/osg/DisplaySettings.cpp
index 1fd685b33..7aa9964c1 100644
--- a/src/osg/DisplaySettings.cpp
+++ b/src/osg/DisplaySettings.cpp
@@ -240,7 +240,7 @@ void DisplaySettings::setDefaults()
 
     _implicitBufferAttachmentRenderMask = DEFAULT_IMPLICIT_BUFFER_ATTACHMENT;
     _implicitBufferAttachmentResolveMask = DEFAULT_IMPLICIT_BUFFER_ATTACHMENT;
-    _glContextVersion = "1.0";
+    _glContextVersion = OSG_GL_CONTEXT_STRING;
     _glContextFlags = 0;
     _glContextProfileMask = 0;
 
diff --git a/src/osg/GL.in b/src/osg/GL.in
index 89c6bace4..ac4a97fe6 100644
--- a/src/osg/GL.in
+++ b/src/osg/GL.in
@@ -39,6 +39,7 @@
 #define OSG_GLES1_FEATURES @OSG_GLES1_FEATURES@
 #define OSG_GLES2_FEATURES @OSG_GLES2_FEATURES@
 #define OSG_GLES3_FEATURES @OSG_GLES3_FEATURES@
+#define OSG_GL_CONTEXT_STRING "@OSG_GL_CONTEXT_STRING@"
 
 
 #ifndef WIN32
diff --git a/src/osg/GraphicsContext.cpp b/src/osg/GraphicsContext.cpp
index e73ec3e6a..409790f29 100644
--- a/src/osg/GraphicsContext.cpp
+++ b/src/osg/GraphicsContext.cpp
@@ -239,7 +239,7 @@ GraphicsContext::Traits::Traits(DisplaySettings* ds):
             swapBarrier(0),
             useMultiThreadedOpenGLEngine(false),
             useCursor(true),
-            glContextVersion("1.0"),
+            glContextVersion(OSG_GL_CONTEXT_STRING),
             glContextFlags(0),
             glContextProfileMask(0),
             sharedContext(0),