Added beginnings of shader composition with the shells of the ShaderComposer and ShaderAttribute classes. This aren't

functional yet, but a useful placeholders for future fucntionality.

include/osg/ShaderAttribute

@@ -0,0 +1,82 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2004 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSG_SHADERATTRIBUTE
+#define OSG_SHADERATTRIBUTE 1
+
+#include <osg/StateAttribute>
+#include <osg/Shader>
+#include <osg/Uniform>
+
+namespace osg {
+
+class OSG_EXPORT ShaderAttribute : public StateAttribute
+{
+    public :
+
+        ShaderAttribute();
+
+        /** Copy constructor using CopyOp to manage deep vs shallow copy. */
+        ShaderAttribute(const ShaderAttribute& sa,const CopyOp& copyop=CopyOp::SHALLOW_COPY);
+
+        META_Object(osg, ShaderAttribute);
+
+        /** return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs. */
+        virtual int compare(const StateAttribute& sa) const;
+
+
+        void setType(Type type);
+        virtual Type getType() const { return _type; }
+
+        unsigned int addShader(Shader* shader);
+        void removeShader(unsigned int i);
+        unsigned int getNumShaders() const { return _shaders.size(); }
+        Shader* getShader(unsigned int i) { return _shaders[i].get(); }
+        Shader* getShader(unsigned int i) const { return _shaders[i].get(); }
+
+
+        unsigned int addUniform(Uniform* uniform);
+        void removeUniform(unsigned int i);
+        unsigned int getNumUniforms() const { return _uniforms.size(); }
+        Uniform* getUniform(unsigned int i) { return _uniforms[i].get(); }
+        const Uniform* getUniform(unsigned int i) const { return _uniforms[i].get(); }
+
+
+        virtual bool getModeUsage(StateAttribute::ModeUsage& usage) const;
+
+        virtual void apply(State& state) const;
+
+        virtual void compose(ShaderComposer& composer) const;
+
+        virtual void compileGLObjects(State& state) const;
+
+        virtual void resizeGLObjectBuffers(unsigned int maxSize);
+
+        virtual void releaseGLObjects(State* state=0) const;
+
+    protected :
+
+        virtual ~ShaderAttribute();
+
+        typedef std::vector< osg::ref_ptr<osg::Shader> > Shaders;
+        typedef std::vector< osg::ref_ptr<osg::Uniform> > Uniforms;
+
+        Type _type;
+        Shaders _shaders;
+        Uniforms _uniforms;
+
+};
+
+}
+
+#endif

include/osg/ShaderComposer

@@ -0,0 +1,43 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSG_SHADERCOMPOSER
+#define OSG_SHADERCOMPOSER 1
+
+#include <osg/Object>
+#include <osg/StateAttribute>
+#include <osg/Program>
+
+namespace osg {
+
+// forward declare osg::State
+class State;
+
+class OSG_EXPORT ShaderComposer : public osg::Object
+{
+    public:
+
+        ShaderComposer();
+        ShaderComposer(const ShaderComposer& sa,const CopyOp& copyop=CopyOp::SHALLOW_COPY);
+        META_Object(osg, ShaderComposer)
+
+
+    protected:
+
+        virtual ~ShaderComposer();
+
+};
+
+}
+
+#endif

include/osg/State

@@ -21,6 +21,7 @@
 #include <osg/BufferObject>
 #include <osg/Observer>
 
+#include <osg/ShaderComposer>
 #include <osg/FrameStamp>
 #include <osg/DisplaySettings>
 #include <osg/Polytope>
@@ -140,6 +141,17 @@ class OSG_EXPORT State : public Referenced, public Observer
         /** Get the current OpenGL context unique ID.*/
         inline unsigned int getContextID() const { return _contextID; }
 
+
+        /** Set the ShaderComposor object that implements shader composition.*/
+        void setShaderComposer(ShaderComposer* sc) { _shaderComposer = sc; }
+
+        /** Get the ShaderComposor object.*/
+        ShaderComposer* getShaderComposer() { return _shaderComposer.get(); }
+
+        /** Get the const ShaderComposor object.*/
+        const ShaderComposer* getShaderComposer() const { return _shaderComposer.get(); }
+
+
         /** Push stateset onto state stack.*/
         void pushStateSet(const StateSet* dstate);
 
@@ -1339,6 +1351,8 @@ class OSG_EXPORT State : public Referenced, public Observer
 
         GraphicsContext*            _graphicsContext;
         unsigned int                _contextID;
+        osg::ref_ptr<ShaderComposer> _shaderComposer;
+
         ref_ptr<FrameStamp>         _frameStamp;
 
         ref_ptr<const RefMatrix>    _identity;

include/osg/StateAttribute

@@ -35,6 +35,7 @@ namespace osg {
 // forward declare NodeVisitor, State & StateSet
 class NodeVisitor;
 class State;
+class ShaderComposer;
 class StateSet;
 class Texture;
 
@@ -315,6 +316,9 @@ class OSG_EXPORT StateAttribute : public Object
           */
         virtual void apply(State&) const {}
 
+        /* compose associated shaders via the ShaderComposer. */
+        virtual void compose(ShaderComposer& composer) const {}
+
         /** Default to nothing to compile - all state is applied immediately. */
         virtual void compileGLObjects(State&) const {}