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

Copyright (c) 2000-2006 Torus Knot Software Ltd
Also see acknowledgements in Readme.html

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program 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 GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.

You may alternatively use this source under the terms of a specific version of
the OGRE Unrestricted License provided you have obtained such a license from
Torus Knot Software Ltd.
-----------------------------------------------------------------------------
*/
#ifndef __SubMesh_H_
#define __SubMesh_H_

#include "OgrePrerequisites.h"

#include "OgreVertexIndexData.h"
#include "OgreMaterial.h"
#include "OgreRenderOperation.h"
#include "OgreVertexBoneAssignment.h"
#include "OgreProgressiveMesh.h"
#include "OgreAnimationTrack.h"

namespace Ogre {

    /** Defines a part of a complete mesh.
        @remarks
            Meshes which make up the definition of a discrete 3D object
            are made up of potentially multiple parts. This is because
            different parts of the mesh may use different materials or
            use different vertex formats, such that a rendering state
            change is required between them.
        @par
            Like the Mesh class, instantiations of 3D objects in the scene
            share the SubMesh instances, and have the option of overriding
            their material differences on a per-object basis if required.
            See the SubEntity class for more information.
    */
	class _OgreExport SubMesh : public SubMeshAlloc
    {
        friend class Mesh;
        friend class MeshSerializerImpl;
        friend class MeshSerializerImpl_v1_2;
        friend class MeshSerializerImpl_v1_1;
    public:
        SubMesh();
        ~SubMesh();


        /// Indicates if this submesh shares vertex data with other meshes or whether it has it's own vertices.
        bool useSharedVertices;

        /// The render operation type used to render this submesh
        RenderOperation::OperationType operationType;

        /** Dedicated vertex data (only valid if useSharedVertices = false).
            @remarks
                This data is completely owned by this submesh.
            @par
                The use of shared or non-shared buffers is determined when
                model data is converted to the OGRE .mesh format.
        */
        VertexData *vertexData;

        /// Face index data
        IndexData *indexData;

        /** Dedicated index map for translate blend index to bone index (only valid if useSharedVertices = false).
            @remarks
                This data is completely owned by this submesh.
            @par
                We collect actually used bones of all bone assignments, and build the
                blend index in 'packed' form, then the range of the blend index in vertex
                data VES_BLEND_INDICES element is continuous, with no gaps. Thus, by
                minimising the world matrix array constants passing to GPU, we can support
                more bones for a mesh when hardware skinning is used. The hardware skinning
                support limit is applied to each set of vertex data in the mesh, in other words, the
                hardware skinning support limit is applied only to the actually used bones of each
                SubMeshes, not all bones across the entire Mesh.
            @par
                Because the blend index is different to the bone index, therefore, we use
                the index map to translate the blend index to bone index.
            @par
                The use of shared or non-shared index map is determined when
                model data is converted to the OGRE .mesh format.
        */
        typedef std::vector<unsigned short> IndexMap;
        IndexMap blendIndexToBoneIndexMap;

        ProgressiveMesh::LODFaceList mLodFaceList;

        /** A list of extreme points on the submesh (optional).
            @remarks
                These points are some arbitrary points on the mesh that are used
                by engine to better sort submeshes by depth. This doesn't matter
                much for non-transparent submeshes, as Z-buffer takes care of invisible
                surface culling anyway, but is pretty useful for semi-transparent
                submeshes because the order in which transparent submeshes must be
                rendered cannot be always correctly deduced from entity position.
            @par
                These points are intelligently chosen from the points that make up
                the submesh, the criteria for choosing them should be that these points
                somewhat characterize the submesh outline, e.g. they should not be
                close to each other, and they should be on the outer hull of the submesh.
                They can be stored in the .mesh file, or generated at runtime
                (see generateExtremes ()).
            @par
                If this array is empty, submesh sorting is done like in older versions -
                by comparing the positions of the owning entity.
         */
        std::vector<Vector3> extremityPoints;

        /// Reference to parent Mesh (not a smart pointer so child does not keep parent alive).
        Mesh* parent;

        /// Sets the name of the Material which this SubMesh will use
        void setMaterialName(const String& matName);
        const String& getMaterialName(void) const;

        /** Returns true if a material has been assigned to the submesh, otherwise returns false.
        */
        bool isMatInitialised(void) const;

        /** Returns a RenderOperation structure required to render this mesh.
            @param 
                rend Reference to a RenderOperation structure to populate.
            @param
                lodIndex The index of the LOD to use. 
        */
        void _getRenderOperation(RenderOperation& rend, ushort lodIndex = 0);

        /** Assigns a vertex to a bone with a given weight, for skeletal animation. 
        @remarks    
            This method is only valid after calling setSkeletonName.
            Since this is a one-off process there exists only 'addBoneAssignment' and
            'clearBoneAssignments' methods, no 'editBoneAssignment'. You should not need
            to modify bone assignments during rendering (only the positions of bones) and OGRE
            reserves the right to do some internal data reformatting of this information, depending
            on render system requirements.
        @par
            This method is for assigning weights to the dedicated geometry of the SubMesh. To assign
            weights to the shared Mesh geometry, see the equivalent methods on Mesh.
        */
        void addBoneAssignment(const VertexBoneAssignment& vertBoneAssign);

        /** Removes all bone assignments for this mesh. 
        @par
            This method is for assigning weights to the dedicated geometry of the SubMesh. To assign
            weights to the shared Mesh geometry, see the equivalent methods on Mesh.
        */
        void clearBoneAssignments(void);

        /// Multimap of verex bone assignments (orders by vertex index)
        typedef std::multimap<size_t, VertexBoneAssignment> VertexBoneAssignmentList;
        typedef MapIterator<VertexBoneAssignmentList> BoneAssignmentIterator;

        /** Gets an iterator for access all bone assignments. 
        @remarks
            Only valid if this SubMesh has dedicated geometry.
        */
        BoneAssignmentIterator getBoneAssignmentIterator(void);

		/** Gets a const reference to the list of bone assignments
		*/
		const VertexBoneAssignmentList& getBoneAssignments() { return mBoneAssignments; }


        /** Must be called once to compile bone assignments into geometry buffer. */
        void _compileBoneAssignments(void);

        typedef ConstMapIterator<AliasTextureNamePairList> AliasTextureIterator;
        /** Gets an constant iterator to access all texture alias names assigned to this submesh. 

        */
        AliasTextureIterator getAliasTextureIterator(void) const;
        /** Adds the alias or replaces an existing one and associates the texture name to it.
        @remarks
          The submesh uses the texture alias to replace textures used in the material applied
          to the submesh.
        @param
            aliasName is the name of the alias.
        @param
            textureName is the name of the texture to be associated with the alias

        */
        void addTextureAlias(const String& aliasName, const String& textureName);
        /** Remove a specific texture alias name from the sub mesh
        @param
            aliasName is the name of the alias to be removed.  If it is not found 
            then it is ignored.
        */
        void removeTextureAlias(const String& aliasName);
        /** removes all texture aliases from the sub mesh
        */
        void removeAllTextureAliases(void);
        /** returns true if the sub mesh has texture aliases
        */
        bool hasTextureAliases(void) const { return !mTextureAliases.empty(); }
        /** Gets the number of texture aliases assigned to the sub mesh.
        */
        size_t getTextureAliasCount(void) const { return mTextureAliases.size(); }

        /**  The current material used by the submesh is copied into a new material
            and the submesh's texture aliases are applied if the current texture alias
            names match those found in the original material.
        @remarks
            The submesh's texture aliases must be setup prior to calling this method.
            If a new material has to be created, the subMesh autogenerates the new name.
            The new name is the old name + "_" + number.
        @return 
            True if texture aliases were applied and a new material was created.
        */
        bool updateMaterialUsingTextureAliases(void);

		/** Get the type of any vertex animation used by dedicated geometry.
		*/
		VertexAnimationType getVertexAnimationType(void) const;

        /** Generate the submesh extremes (@see extremityPoints).
        @param count
            Number of extreme points to compute for the submesh.
        */
        void generateExtremes(size_t count);

		/** Returns true(by default) if the submesh should be included in the mesh EdgeList, otherwise returns false.
        */		
		bool isBuildEdgesEnabled(void) const { return mBuildEdgesEnabled; }
		void setBuildEdgesEnabled(bool b);

    protected:

        /// Name of the material this SubMesh uses.
        String mMaterialName;

        /// Is there a material yet?
        bool mMatInitialised;

        /// paired list of texture aliases and texture names
        AliasTextureNamePairList mTextureAliases;

        VertexBoneAssignmentList mBoneAssignments;

        /// Flag indicating that bone assignments need to be recompiled
        bool mBoneAssignmentsOutOfDate;

		/// Type of vertex animation for dedicated vertex data (populated by Mesh)
		mutable VertexAnimationType mVertexAnimationType;

		/// Is Build Edges Enabled
		bool mBuildEdgesEnabled;

        /// Internal method for removing LOD data
        void removeLodLevels(void);


    };

} // namespace

#endif

