From 5c4800c7743e61c31f806986cbc2054f84bc5036 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Tue, 22 Oct 2013 11:17:29 +0000
Subject: [PATCH] Fixed handling of in scene graph osg::Program being overriden
 by shader composition.

---
 src/osg/State.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/osg/State.cpp b/src/osg/State.cpp
index a09e34b0f..6f9794aaa 100644
--- a/src/osg/State.cpp
+++ b/src/osg/State.cpp
@@ -484,12 +484,18 @@ void State::apply(const StateSet* dstate)
             else if (unit<_textureAttributeMapList.size()) applyAttributeMapOnTexUnit(unit,_textureAttributeMapList[unit]);
         }
 
+        const Program::PerContextProgram* previousLastAppliedProgramObject = _lastAppliedProgramObject;
+
         applyModeList(_modeMap,dstate->getModeList());
         applyAttributeList(_attributeMap,dstate->getAttributeList());
 
         if (_shaderCompositionEnabled)
         {
-            applyShaderComposition();
+            if (previousLastAppliedProgramObject == _lastAppliedProgramObject || _lastAppliedProgramObject==0)
+            {
+                // No program has been applied by the StateSet stack so assume shader composition is required
+                applyShaderComposition();
+            }
         }
 
         if (dstate->getUniformList().empty())
@@ -911,7 +917,7 @@ void State::initializeExtensionProcs()
     if ( osg::getGLVersionNumber() >= 2.0 || osg::isGLExtensionSupported(_contextID,"GL_ARB_vertex_shader") || OSG_GLES2_FEATURES)
     {
         glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS,&_glMaxTextureUnits);
-        if(OSG_GLES2_FEATURES)       
+        if(OSG_GLES2_FEATURES)
             _glMaxTextureCoords = _glMaxTextureUnits;
         else
             glGetIntegerv(GL_MAX_TEXTURE_COORDS,&_glMaxTextureCoords);