/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __GLSLESLinkProgramManager_H__
#define __GLSLESLinkProgramManager_H__

#include "OgreGLES2Prerequisites.h"
#include "OgreSingleton.h"

#include "OgreGLSLESExtSupport.h"
#include "OgreGLSLESLinkProgram.h"
#include "OgreGLSLESProgramManagerCommon.h"

namespace Ogre {


    /** Ogre assumes that there are separate vertex and fragment
        programs to deal with but GLSL ES has one program object that
        represents the active vertex and fragment shader objects
        during a rendering state.  GLSL Vertex and fragment shader
        objects are compiled separately and then attached to a program
        object and then the program object is linked.  Since Ogre can
        only handle one vertex program and one fragment program being
        active in a pass, the GLSL ES Link Program Manager does the same.
        The GLSL ES Link program manager acts as a state machine and
        activates a program object based on the active vertex and
        fragment program.  Previously created program objects are
        stored along with a unique key in a hash_map for quick
        retrieval the next time the program object is required.
    */

    class _OgreGLES2Export GLSLESLinkProgramManager : public GLSLESProgramManagerCommon, public Singleton<GLSLESLinkProgramManager>
    {

    private:
    
        typedef map<uint64, GLSLESLinkProgram*>::type LinkProgramMap;
        typedef LinkProgramMap::iterator LinkProgramIterator;

        /// Container holding previously created program objects 
        LinkProgramMap mLinkPrograms; 

        /// Active objects defining the active rendering gpu state
        GLSLESLinkProgram* mActiveLinkProgram;

        typedef map<String, GLenum>::type StringToEnumMap;
        StringToEnumMap mTypeEnumMap;

    public:

        GLSLESLinkProgramManager(void);

        ~GLSLESLinkProgramManager(void);

        /** Get the program object that links the two active shader
            objects together if a program object was not already
            created and linked a new one is created and linked
        */
        GLSLESLinkProgram* getActiveLinkProgram(void);

        /** Set the active vertex shader for the next rendering state.
            The active program object will be cleared. Normally
            called from the GLSLESShader::bindProgram and
            unbindProgram methods
        */
        void setActiveVertexShader(GLSLESShader* vertexShader);
        /** Set the active fragment shader for the next rendering
            state.  The active program object will be cleared.
            Normally called from the GLSLESShader::bindProgram and
            unbindProgram methods
        */
        void setActiveFragmentShader(GLSLESShader* fragmentShader);

        static GLSLESLinkProgramManager& getSingleton(void);
        static GLSLESLinkProgramManager* getSingletonPtr(void);

    };

}

#endif // __GLSLESLinkProgramManager_H__
