//
//   Copyright 2013 Pixar
//
//   Licensed under the Apache License, Version 2.0 (the "Apache License")
//   with the following modification; you may not use this file except in
//   compliance with the Apache License and the following modification to it:
//   Section 6. Trademarks. is deleted and replaced with:
//
//   6. Trademarks. This License does not grant permission to use the trade
//      names, trademarks, service marks, or product names of the Licensor
//      and its affiliates, except as required to comply with Section 4(c) of
//      the License and to reproduce the content of the NOTICE file.
//
//   You may obtain a copy of the Apache License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the Apache License with the above modification is
//   distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
//   KIND, either express or implied. See the Apache License for the specific
//   language governing permissions and limitations under the Apache License.
//

#ifndef FAR_BILINEAR_SUBDIVISION_TABLES_H
#define FAR_BILINEAR_SUBDIVISION_TABLES_H

#include "../version.h"

#include "../far/subdivisionTables.h"

#include <cassert>
#include <vector>

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

/// \brief Bilinear subdivision scheme tables.
///
/// Bilinear tables store the indexing tables required in order to compute
/// the refined positions of a mesh without the help of a hierarchical data
/// structure. The advantage of this representation is its ability to be executed
/// in a massively parallel environment without data dependencies.
///
template <class U> class FarBilinearSubdivisionTables : public FarSubdivisionTables<U> {

public:

    /// Returns the number of indexing tables needed to represent this particular
    /// subdivision scheme.
    virtual int GetNumTables() const { return 7; }

private:
    template <class X, class Y> friend class FarBilinearSubdivisionTablesFactory;
    template <class X, class Y> friend class FarMultiMeshFactory;
    template <class CONTROLLER> friend class FarComputeController;

    FarBilinearSubdivisionTables( FarMesh<U> * mesh, int maxlevel );

    // Compute-kernel applied to vertices resulting from the refinement of a face.
    void computeFacePoints(int vertexOffset, int tableOffset, int start, int end, void * clientdata) const;

    // Compute-kernel applied to vertices resulting from the refinement of an edge.
    void computeEdgePoints(int vertexOffset, int tableOffset, int start, int end, void * clientdata) const;

    // Compute-kernel applied to vertices resulting from the refinement of a vertex
    void computeVertexPoints(int vertexOffset, int tableOffset, int start, int end, void * clientdata) const;

};

template <class U>
FarBilinearSubdivisionTables<U>::FarBilinearSubdivisionTables( FarMesh<U> * mesh, int maxlevel ) :
    FarSubdivisionTables<U>(mesh, maxlevel)
{ }

//
// Face-vertices compute Kernel - completely re-entrant
//

template <class U> void
FarBilinearSubdivisionTables<U>::computeFacePoints( int offset, int tableOffset, int start, int end, void * clientdata ) const {

    assert(this->_mesh);

    U * vsrc = &this->_mesh->GetVertices().at(0),
      * vdst = vsrc + offset + start;

    for (int i=start+tableOffset; i<end+tableOffset; ++i, ++vdst ) {

        vdst->Clear(clientdata);

        int h = this->_F_ITa[2*i  ],
            n = this->_F_ITa[2*i+1];
        float weight = 1.0f/n;

        for (int j=0; j<n; ++j) {
             vdst->AddWithWeight( vsrc[ this->_F_IT[h+j] ], weight, clientdata );
             vdst->AddVaryingWithWeight( vsrc[ this->_F_IT[h+j] ], weight, clientdata );
        }
    }
}

//
// Edge-vertices compute Kernel - completely re-entrant
//

template <class U> void
FarBilinearSubdivisionTables<U>::computeEdgePoints( int offset,  int tableOffset, int start, int end, void * clientdata ) const {

    assert(this->_mesh);

    U * vsrc = &this->_mesh->GetVertices().at(0),
      * vdst = vsrc + offset + start;

    for (int i=start+tableOffset; i<end+tableOffset; ++i, ++vdst ) {

        vdst->Clear(clientdata);

        int eidx0 = this->_E_IT[2*i+0],
            eidx1 = this->_E_IT[2*i+1];

        vdst->AddWithWeight( vsrc[eidx0], 0.5f, clientdata );
        vdst->AddWithWeight( vsrc[eidx1], 0.5f, clientdata );

        vdst->AddVaryingWithWeight( vsrc[eidx0], 0.5f, clientdata );
        vdst->AddVaryingWithWeight( vsrc[eidx1], 0.5f, clientdata );
    }
}

//
// Vertex-vertices compute Kernel - completely re-entrant
//

template <class U> void
FarBilinearSubdivisionTables<U>::computeVertexPoints( int offset, int tableOffset, int start, int end, void * clientdata ) const {

    assert(this->_mesh);

    U * vsrc = &this->_mesh->GetVertices().at(0),
      * vdst = vsrc + offset + start;

    for (int i=start+tableOffset; i<end+tableOffset; ++i, ++vdst ) {

        vdst->Clear(clientdata);

        int p = this->_V_ITa[i];   // index of the parent vertex

        vdst->AddWithWeight( vsrc[p], 1.0f, clientdata );
        vdst->AddVaryingWithWeight( vsrc[p], 1.0f, clientdata );
    }
}

} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

} // end namespace OpenSubdiv

#endif /* FAR_BILINEAR_SUBDIVISION_TABLES_H */
