/*

-----------------------------------------------------------------------------

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 __HighLevelGpuProgram_H__

#define __HighLevelGpuProgram_H__

#include "OgrePrerequisites.h"

#include "OgreGpuProgram.h"

#include "OgreHeaderPrefix.h"

namespace Ogre {

    /** \addtogroup Core

    *  @{

    */

    /** \addtogroup Resources

    *  @{

    */

    /** Abstract base class representing a high-level program (a vertex or

        fragment program).

        High-level programs are vertex and fragment programs written in a high-level

        language such as Cg or HLSL, and as such do not require you to write assembler code

        like GpuProgram does. However, the high-level program does eventually 

        get converted (compiled) into assembler and then eventually microcode which is

        what runs on the GPU. As well as the convenience, some high-level languages like Cg allow

        you to write a program which will operate under both Direct3D and OpenGL, something

        which you cannot do with just GpuProgram (which requires you to write 2 programs and

        use each in a Technique to provide cross-API compatibility). Ogre will be creating

        a GpuProgram for you based on the high-level program, which is compiled specifically 

        for the API being used at the time, but this process is transparent.

    @par

        You cannot create high-level programs direct - use HighLevelGpuProgramManager instead.

        Plugins can register new implementations of HighLevelGpuProgramFactory in order to add

        support for new languages without requiring changes to the core Ogre API. To allow 

        custom parameters to be set, this class extends StringInterface - the application

        can query on the available custom parameters and get/set them without having to 

        link specifically with it.

    */

    class _OgreExport HighLevelGpuProgram : public GpuProgram

    {

    protected:

        /// Whether the high-level program (and it's parameter defs) is loaded

        bool mHighLevelLoaded;

        /// Have we built the name->index parameter map yet?

        bool mConstantDefsBuilt;

        /// The underlying assembler program

        GpuProgramPtr mAssemblerProgram;

        /// Preprocessor options

        String mPreprocessorDefines;

        /// Entry point for this program

        String mEntryPoint;

        /// in-situ parsing of defines

        static std::vector<std::pair<const char*, const char*>> parseDefines(String& defines);

        String appendBuiltinDefines(String defines);

        /// Internal load high-level portion if not loaded

        virtual void loadHighLevel(void);

        /// Internal unload high-level portion if loaded

        virtual void unloadHighLevel(void);

        /** Internal method for creating an appropriate low-level program from this

        high-level program, must be implemented by subclasses. */

        virtual void createLowLevelImpl(void) = 0;

        /// Internal unload implementation, must be implemented by subclasses

        virtual void unloadHighLevelImpl(void) = 0;

        /// Populate the passed parameters with name->index map

        void populateParameterNames(const GpuProgramParametersSharedPtr& params);

        /** Build the constant definition map, must be overridden.

        @note The implementation must fill in the (inherited) mConstantDefs field at a minimum, 

            and if the program requires that parameters are bound using logical 

            parameter indexes then the mLogicalToPhysical and mIntLogicalToPhysical

            maps must also be populated.

        */

        virtual void buildConstantDefinitions() = 0;

        /** @copydoc Resource::loadImpl */

        void loadImpl() override;

        /** @copydoc Resource::unloadImpl */

        void unloadImpl() override;

        void setupBaseParamDictionary() override;

    public:

        /** Constructor, should be used only by factory classes. */

        HighLevelGpuProgram(ResourceManager* creator, const String& name, ResourceHandle handle,

            const String& group, bool isManual = false, ManualResourceLoader* loader = 0);

        ~HighLevelGpuProgram();

        /** Creates a new parameters object compatible with this program definition. 

            Unlike low-level assembly programs, parameters objects are specific to the

            program and therefore must be created from it rather than by the 

            HighLevelGpuProgramManager. This method creates a new instance of a parameters

            object containing the definition of the parameters this program understands.

        */

        GpuProgramParametersSharedPtr createParameters(void) override;

        /** @copydoc GpuProgram::_getBindingDelegate */

        GpuProgram* _getBindingDelegate(void) override { return mAssemblerProgram.get(); }

        /** Get the full list of GpuConstantDefinition instances.

        @note

        Only available if this parameters object has named parameters.

        */

        const GpuNamedConstants& getConstantDefinitions() override;

        size_t calculateSize(void) const override;

        /** Sets the preprocessor defines used to compile the program. */

        void setPreprocessorDefines(const String& defines) { mPreprocessorDefines = defines; }

        /** Gets the preprocessor defines used to compile the program. */

        const String& getPreprocessorDefines(void) const { return mPreprocessorDefines; }

        /** Sets the entry point for this program i.e, the first method called. */

        void setEntryPoint(const String& entryPoint) { mEntryPoint = entryPoint; }

        /** Gets the entry point defined for this program. */

        const String& getEntryPoint(void) const { return mEntryPoint; }

        /// Scan the source for \#include and replace with contents from OGRE resources

        static String _resolveIncludes(const String& source, Resource* resourceBeingLoaded, const String& fileName, bool supportsFilename = false);

    };

    /** @} */

    /** @} */

}

#include "OgreHeaderSuffix.h"

#endif