/*  -*-c++-*-
 *  Copyright (C) 2009 Cedric Pinson <cedric.pinson@plopbyte.net>
 *
 * 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 OSGANIMATION_RIGTRANSFORM_SOFTWARE
#define OSGANIMATION_RIGTRANSFORM_SOFTWARE 1

#include <osgAnimation/Export>
#include <osgAnimation/RigTransform>
#include <osgAnimation/Bone>
#include <osgAnimation/VertexInfluence>
#include <osg/observer_ptr>

namespace osgAnimation
{

    class RigGeometry;

    /// This class manage format for software skinning
    class OSGANIMATION_EXPORT RigTransformSoftware : public RigTransform
    {
    public:

        RigTransformSoftware();
        virtual void operator()(RigGeometry&);


        class BoneWeight
        {
        public:
            BoneWeight(Bone* bone, float weight) : _bone(bone), _weight(weight) {}
            const Bone* getBone() const { return _bone.get(); }
            float getWeight() const { return _weight; }
            void setWeight(float w) { _weight = w; }
        protected:
            osg::observer_ptr<Bone> _bone;
            float _weight;
        };

        typedef std::vector<BoneWeight> BoneWeightList;
        typedef std::vector<int> VertexList;

        class UniqBoneSetVertexSet
        {
        public:
            BoneWeightList& getBones() { return _bones; }
            VertexList& getVertexes() { return _vertexes; }

            void resetMatrix()
            {
                _result.set(0, 0, 0, 0,
                            0, 0, 0, 0,
                            0, 0, 0, 0,
                            0, 0, 0, 1);
            }
            void accummulateMatrix(const osg::Matrix& invBindMatrix, const osg::Matrix& matrix, osg::Matrix::value_type weight)
            {
                osg::Matrix m = invBindMatrix * matrix;
                osg::Matrix::value_type* ptr = m.ptr();
                osg::Matrix::value_type* ptrresult = _result.ptr();
                ptrresult[0] += ptr[0] * weight;
                ptrresult[1] += ptr[1] * weight;
                ptrresult[2] += ptr[2] * weight;

                ptrresult[4] += ptr[4] * weight;
                ptrresult[5] += ptr[5] * weight;
                ptrresult[6] += ptr[6] * weight;

                ptrresult[8] += ptr[8] * weight;
                ptrresult[9] += ptr[9] * weight;
                ptrresult[10] += ptr[10] * weight;

                ptrresult[12] += ptr[12] * weight;
                ptrresult[13] += ptr[13] * weight;
                ptrresult[14] += ptr[14] * weight;
            }
            void computeMatrixForVertexSet()
            {
                if (_bones.empty())
                {
                    osg::notify(osg::WARN) << this << " RigTransformSoftware::UniqBoneSetVertexSet no bones found" << std::endl;
                    _result = osg::Matrix::identity();
                    return;
                }
                resetMatrix();

                int size = _bones.size();
                for (int i = 0; i < size; i++)
                {
                    const Bone* bone = _bones[i].getBone();
                    if (!bone)
                    {
                        osg::notify(osg::WARN) << this << " RigTransformSoftware::computeMatrixForVertexSet Warning a bone is null, skip it" << std::endl;
                        continue;
                    }
                    const osg::Matrix& invBindMatrix = bone->getInvBindMatrixInSkeletonSpace();
                    const osg::Matrix& matrix = bone->getMatrixInSkeletonSpace();
                    osg::Matrix::value_type w = _bones[i].getWeight();
                    accummulateMatrix(invBindMatrix, matrix, w);
                }
            }
            const osg::Matrix& getMatrix() const { return _result;}
        protected:
            BoneWeightList _bones;
            VertexList _vertexes;
            osg::Matrix _result;
        };



        template <class V> void compute(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
        {
            // the result of matrix mult should be cached to be used for vertexes transform and normal transform and maybe other computation
            int size = _boneSetVertexSet.size();
            for (int i = 0; i < size; i++)
            {
                UniqBoneSetVertexSet& uniq = _boneSetVertexSet[i];
                uniq.computeMatrixForVertexSet();
                osg::Matrix matrix =  transform * uniq.getMatrix() * invTransform;

                const VertexList& vertexes = uniq.getVertexes();
                int vertexSize = vertexes.size();
                for (int j = 0; j < vertexSize; j++)
                {
                    int idx = vertexes[j];
                    dst[idx] = src[idx] * matrix;
                }
            }
        }


        template <class V> void computeNormal(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
        {
            int size = _boneSetVertexSet.size();
            for (int i = 0; i < size; i++)
            {
                UniqBoneSetVertexSet& uniq = _boneSetVertexSet[i];
                uniq.computeMatrixForVertexSet();
                osg::Matrix matrix =  transform * uniq.getMatrix() * invTransform;

                const VertexList& vertexes = uniq.getVertexes();
                int vertexSize = vertexes.size();
                for (int j = 0; j < vertexSize; j++)
                {
                    int idx = vertexes[j];
                    dst[idx] = osg::Matrix::transform3x3(src[idx],matrix);
                }
            }
        }

    protected:

        bool init(RigGeometry&);
        void initVertexSetFromBones(const BoneMap& map, const VertexInfluenceSet::UniqVertexSetToBoneSetList& influence);
        std::vector<UniqBoneSetVertexSet> _boneSetVertexSet;

        bool _needInit;

    };
}

#endif
