/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 Robert Osfield 
 * Copyright (C) 2003 3Dlabs Inc. Ltd.
 *
 * This application is open source and may be redistributed and/or modified   
 * freely and without restriction, both in commericial and non commericial
 * applications, as long as this copyright notice is maintained.
 * 
 * This application 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.
*/

/* file:	include/osgGL2/ProgramObject
 * author:	Mike Weiblen 2003-07-14
 *
 * See http://www.3dlabs.com/opengl2/ for more information regarding
 * the OpenGL Shading Language.
*/


#ifndef OSGGL2_PROGRAMOBJECT
#define OSGGL2_PROGRAMOBJECT 1

#include <osg/State>
#include <osg/StateAttribute>
#include <osg/buffered_value>
#include <osg/ref_ptr>

#include <osgGL2/Export>
#include <osgGL2/Extensions>

#include <string>


namespace osgGL2 {



///////////////////////////////////////////////////////////////////////////

class ShaderObject;

/** Encapsulates the OpenGL Shading Language ProgramObject */
class OSGGL2_EXPORT ProgramObject : public osg::StateAttribute
{
    public:

        ProgramObject();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        ProgramObject(const ProgramObject& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);

        META_StateAttribute(osgGL2, ProgramObject, PROGRAMOBJECT);

        /** return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs.*/
        virtual int compare(const osg::StateAttribute& sa) const
        {
            // check the types are equal and then create the rhs variable
            // used by the COMPARE_StateAttribute_Paramter macro's below.
            COMPARE_StateAttribute_Types(ProgramObject,sa)

            // compare each parameter in turn against the rhs.
            COMPARE_StateAttribute_Parameter(_shaderObjectList);
            // COMPARE_StateAttribute_Parameter(_pcpoList);

            return 0; // passed all the above comparison macro's, must be equal.
        }

        virtual void getAssociatedModes(std::vector<GLMode>& ) const {}

	virtual void apply(osg::State& state) const;

	virtual void compile(osg::State& state) const { apply(state); }

        // data access methods.

        /** Force a relink on next apply() of associated glProgramObject. */
        void dirtyProgramObject();        

	void addShader( ShaderObject* shader );
        
        /** use deleteObject instead of glDeleteObject to allow
          * GL2 Objects to cached until they can be deleted
          * by the OpenGL context in which they were created, specified
          * by contextID.*/
        static void deleteObject(unsigned int contextID, GLhandleARB handle);

        /** flush all the cached glProgramObjects which need to be deleted
          * in the OpenGL context related to contextID.*/
        static void flushDeletedGL2Objects(unsigned int contextID,double currentTime, double& availableTime);

    protected:

        virtual ~ProgramObject();

	typedef std::vector< osg::ref_ptr<ShaderObject> > ShaderObjectList;
	ShaderObjectList _shaderObjectList;


	class OSGGL2_EXPORT PerContextProgObj : public osg::Referenced
	{
	    public:
		PerContextProgObj(const ProgramObject* parent, Extensions* extensions);
		PerContextProgObj(const PerContextProgObj& rhs);

		GLhandleARB& getHandle() {return _handle;}

		bool isDirty() const {return _dirty;}
		void markAsDirty() {_dirty = true; }
		void markAsClean() {_dirty = false;}
		bool build() const;
		void use() const;

		void markAsAttached() {_unattached = false;}
		bool isUnattached() const {return _unattached;}

	    protected:
		PerContextProgObj() {};
		~PerContextProgObj();

		const ProgramObject* _parent;
		osg::ref_ptr<Extensions> _extensions;
		GLhandleARB _handle;
		bool _dirty;
		bool _unattached;
	};

        typedef osg::buffered_value< osg::ref_ptr<PerContextProgObj> > PCPOList;
        mutable PCPOList _pcpoList;

        PerContextProgObj* getPCPO(unsigned int contextID) const;

};


///////////////////////////////////////////////////////////////////////////

/** Encapsulates the OpenGL Shading Language ShaderObject */
class OSGGL2_EXPORT ShaderObject : public osg::Object
{
    public:

	enum Type {
	    VERTEX = GL_VERTEX_SHADER_ARB,
	    FRAGMENT = GL_FRAGMENT_SHADER_ARB,
	    UNKNOWN = -1
	};

        ShaderObject();
        ShaderObject(Type type);
        ShaderObject(Type type, const char* sourceText);

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        ShaderObject(const ShaderObject& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
        META_Object(osgGL2, ShaderObject);

        // data access methods.

	void setShaderSource( const char* sourceText );
	inline const std::string& getShaderSource() const {return _shaderSource; }
	bool loadShaderSourceFromFile( const char* fileName );
	Type getType() const { return _type; }

        /** Force a recompile on next apply() of associated glShaderObject. */
        void dirtyShaderObject();        

	bool build(unsigned int contextID) const;
	void attach(unsigned int contextID, GLhandleARB progObj) const;

    protected:

        virtual ~ShaderObject();

	std::string _shaderSource;
	Type _type;

	class OSGGL2_EXPORT PerContextShaderObj : public osg::Referenced
	{
	    public:
		PerContextShaderObj(const ShaderObject* parent, Extensions* extensions);
		PerContextShaderObj(const PerContextShaderObj& rhs);

		GLhandleARB& getHandle() {return _handle;}

		bool isDirty() const {return _dirty;}
		void markAsDirty() {_dirty = true; }
		void markAsClean() {_dirty = false;}
		bool build();

		void attach(GLhandleARB progObj);

	    protected:
		PerContextShaderObj() {};
		~PerContextShaderObj();

		const ShaderObject* _parent;
		osg::ref_ptr<Extensions> _extensions;
		GLhandleARB _handle;
		bool _dirty;
	};

        typedef osg::buffered_value< osg::ref_ptr<PerContextShaderObj> > PCSOList;
        mutable PCSOList _pcsoList;

        PerContextShaderObj* getPCSO(unsigned int contextID) const;

};

}

#endif