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#ifndef OSD_UTIL_MESH_BATCH_H
#define OSD_UTIL_MESH_BATCH_H

#include "../version.h"
#include "../far/multiMeshFactory.h"
#include "../far/patchTables.h"
#include "../osd/vertexDescriptor.h"
#include "../osd_util/meshHandle.h"

#include <vector>

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

template <class U> class FarMesh;
class OsdVertex;

// ----------------------------------------------------------------------------
// OsdUtilMeshBatchBase
//
//  XXX: abstract...?
//  base batching class which holds farMultiMesh and range information of mesh handles.
// 
template <typename DRAW_CONTEXT>
class OsdUtilMeshBatchBase {
public:
    typedef DRAW_CONTEXT DrawContext;

    virtual ~OsdUtilMeshBatchBase();

    virtual typename DrawContext::VertexBufferBinding BindVertexBuffer() = 0;
    virtual DrawContext * GetDrawContext() const = 0;

    int GetVertexOffset(int meshIndex) const { return _vertexOffsets[meshIndex]; }
    int GetPtexFaceOffset(int meshIndex) const { return _ptexFaceOffsets[meshIndex]; }
    int GetQuadOffset(int meshIndex) const { return _quadOffsets[meshIndex]; }
    int GetQuadCount(int meshIndex) const { return _quadCounts[meshIndex]; }

    virtual void InitializeVertexBuffers(int numVertexElements, int numVaryingElements) = 0;

    // similar methods to OsdGLMesh
    virtual void UpdateCoarseVertices(const OsdUtilMeshHandle &handle, const float *ptrs, int numVertices) = 0;
    virtual void FinalizeUpdate() = 0;
 
    OsdDrawContext::PatchArrayVector const & GetPatchArrays(const OsdUtilMeshHandle &meshHandle) const;

    const typename OsdUtilMeshHandle::Collection & GetMeshHandles() const { return _meshHandles; }

    int GetBatchIndex() const { return _batchIndex; }

    int GetNumPtexFaces() const { return _numPtexFaces; }

protected:
    OsdUtilMeshBatchBase(const std::vector<FarMesh<OsdVertex> const * > &meshVector, int batchIndex);

    void setMeshDirty(int meshIndex);
    void resetMeshDirty();
    void updatePatchArrays(int numVertexElements);

    FarKernelBatchVector getKernelBatches();

    FarMesh <OsdVertex> * _GetFarMesh() const { return _farMultiMesh; }

private:
    typename OsdUtilMeshHandle::Collection _meshHandles;
    FarMesh <OsdVertex> *_farMultiMesh;
    std::vector<OsdDrawContext::PatchArrayVector> _multiPatchArrays;
    FarKernelBatchVector _allKernelBatches;

    std::vector<int>           _vertexOffsets;
    std::vector<int>           _ptexFaceOffsets;
    std::vector<bool>          _dirtyFlags;

    std::vector<int>           _quadOffsets;  // for uniform subdivision
    std::vector<int>           _quadCounts;   // for uniform subdivision

    int _batchIndex;
    int _numPtexFaces;
};

// ----------------------------------------------------------------------------
// OsdUtilMeshBatch
//
//  derived batching class which contains vertexbuffer, computecontext, drawcontext
// 
template <typename VERTEX_BUFFER, typename DRAW_CONTEXT, typename COMPUTE_CONTROLLER>
class OsdUtilMeshBatch : public OsdUtilMeshBatchBase<DRAW_CONTEXT> {
public:
    typedef VERTEX_BUFFER VertexBuffer;
    typedef typename COMPUTE_CONTROLLER::ComputeContext ComputeContext;
    typedef DRAW_CONTEXT DrawContext;
    typedef COMPUTE_CONTROLLER ComputeController;
    typedef OsdUtilMeshBatchBase<DRAW_CONTEXT> Base;
    
    // XXX: not happy with retaining compute controller..
    OsdUtilMeshBatch(ComputeController *computeController,
                     const std::vector<FarMesh<OsdVertex> const * > &meshVector, int batchIndex);

    virtual ~OsdUtilMeshBatch();

    virtual void InitializeVertexBuffers(int numVertexElements, int numVaryingElements);

    virtual typename DrawContext::VertexBufferBinding BindVertexBuffer() { return _vertexBuffer->BindVBO(); }
    virtual DrawContext * GetDrawContext() const { return _drawContext; }

    // update API
    virtual void UpdateCoarseVertices(const OsdUtilMeshHandle &handle,
                                      const float *ptrs, int numVertices) {

        assert(handle.batchIndex == Base::GetBatchIndex());

        Base::setMeshDirty(handle.meshIndex);

        _vertexBuffer->UpdateData(ptrs, Base::GetVertexOffset(handle.meshIndex), numVertices);
    }

    // utility function
    virtual void FinalizeUpdate() {
        // create kernel batch for dirty handles
        
        FarKernelBatchVector batches = Base::getKernelBatches();
        Base::resetMeshDirty();

        _computeController->Refine(_computeContext, batches, _vertexBuffer);
    }

    VertexBuffer *GetVertexBuffer() const { return _vertexBuffer; }
    VertexBuffer *GetVaryingBuffer() const { return _varyingBuffer; }

private:
    ComputeController *_computeController;
    ComputeContext *_computeContext;

    VertexBuffer *_vertexBuffer, *_varyingBuffer;
    DrawContext *_drawContext;
};

// -----------------------------------------------------------------------------
template <typename DRAW_CONTEXT>
OsdUtilMeshBatchBase<DRAW_CONTEXT>::
    OsdUtilMeshBatchBase(const std::vector<FarMesh<OsdVertex> const * > &meshVector, int batchIndex) :
        _farMultiMesh(NULL), _batchIndex(batchIndex) {

    // create multimesh
    FarMultiMeshFactory<OsdVertex> multiMeshFactory;
    _farMultiMesh = multiMeshFactory.Create(meshVector);

    // copy batches
    _allKernelBatches = _farMultiMesh->GetKernelBatches();

    FarPatchTables const * patchTables = _farMultiMesh->GetPatchTables();
    
    // prepare patch arrays
    std::vector<FarPatchTables::PatchArrayVector> const & multiFarPatchArray = multiMeshFactory.GetMultiPatchArrays();

    // create osd patch array per mesh (note: numVertexElements will be updated later on InitializeVertexBuffers)
    _multiPatchArrays.resize(multiFarPatchArray.size());
    for (int i = 0; i < (int)multiFarPatchArray.size(); ++i) {
        OsdDrawContext::ConvertPatchArrays(multiFarPatchArray[i], _multiPatchArrays[i], patchTables->GetMaxValence(), 0);
    }

    bool adaptive = (patchTables != 0);

    _numPtexFaces = _farMultiMesh->GetNumPtexFaces();

    // create mesh handles and prepare patch offsets
    _meshHandles.reserve(meshVector.size());
    int vertexOffset = 0, ptexFaceOffset = 0, quadOffset = 0;
    for (size_t i = 0; i < meshVector.size(); ++i) {
        int numVertices = meshVector[i]->GetNumVertices();
        int numPtexFaces = meshVector[i]->GetNumPtexFaces();

        int maxLevel = meshVector[i]->GetSubdivisionTables()->GetMaxLevel();
        int numQuads = adaptive ? 0 : meshVector[i]->GetFaceVertices(maxLevel-1).size()/4;

        _meshHandles.push_back(OsdUtilMeshHandle(batchIndex, (int)i));

        _vertexOffsets.push_back(vertexOffset);
        _ptexFaceOffsets.push_back(ptexFaceOffset);
        _quadOffsets.push_back(quadOffset);
        _quadCounts.push_back(numQuads);

        vertexOffset += numVertices;
        ptexFaceOffset += numPtexFaces;

        quadOffset += numQuads;
    }
    _dirtyFlags.resize(meshVector.size());
    resetMeshDirty();
}
template <typename DRAW_CONTEXT>
OsdUtilMeshBatchBase<DRAW_CONTEXT>::~OsdUtilMeshBatchBase() {
    delete _farMultiMesh;
}

template <typename DRAW_CONTEXT> void
OsdUtilMeshBatchBase<DRAW_CONTEXT>::setMeshDirty(int meshIndex) {

    assert(meshIndex < (int)_dirtyFlags.size());
    _dirtyFlags[meshIndex] = true;
}

template <typename DRAW_CONTEXT> void
OsdUtilMeshBatchBase<DRAW_CONTEXT>::resetMeshDirty() {
    std::fill(_dirtyFlags.begin(), _dirtyFlags.end(), false);
}

template <typename DRAW_CONTEXT> void
OsdUtilMeshBatchBase<DRAW_CONTEXT>::updatePatchArrays(int numVertexElements) {
    for (int i = 0; i < (int)_multiPatchArrays.size(); ++i) {
        for (int j = 0; j < (int)_multiPatchArrays[i].size(); ++j) {
            OsdDrawContext::PatchDescriptor desc = _multiPatchArrays[i][j].GetDescriptor();
            desc.SetNumElements(numVertexElements);
            _multiPatchArrays[i][j].SetDescriptor(desc);
        }
    }
}

template <typename DRAW_CONTEXT> FarKernelBatchVector
OsdUtilMeshBatchBase<DRAW_CONTEXT>::getKernelBatches() {
    FarKernelBatchVector result;
    for (FarKernelBatchVector::const_iterator it = _allKernelBatches.begin();
         it != _allKernelBatches.end(); ++it) {
        if (_dirtyFlags[it->GetMeshIndex()]) {
            result.push_back(*it);
        }
    }
    return result;
}

template <typename DRAW_CONTEXT> OsdDrawContext::PatchArrayVector const &
OsdUtilMeshBatchBase<DRAW_CONTEXT>::GetPatchArrays(const OsdUtilMeshHandle &meshHandle) const {
    return _multiPatchArrays[meshHandle.meshIndex];
}

// -----------------------------------------------------------------------------
template <typename VERTEX_BUFFER, typename DRAW_CONTEXT, typename COMPUTE_CONTROLLER>
OsdUtilMeshBatch<VERTEX_BUFFER, DRAW_CONTEXT, COMPUTE_CONTROLLER>::
    OsdUtilMeshBatch(ComputeController *computeController,
                     const std::vector<FarMesh<OsdVertex> const * > &meshVector, int batchIndex) :
         OsdUtilMeshBatchBase<DRAW_CONTEXT>(meshVector, batchIndex),
             _computeController(computeController),
             _computeContext(NULL), _vertexBuffer(NULL), _varyingBuffer(NULL), _drawContext(NULL) {
        
    // create compute contexts
    _computeContext = ComputeContext::Create(Base::_GetFarMesh());
}

template <typename VERTEX_BUFFER, typename DRAW_CONTEXT, typename COMPUTE_CONTROLLER>
OsdUtilMeshBatch<VERTEX_BUFFER, DRAW_CONTEXT, COMPUTE_CONTROLLER>::~OsdUtilMeshBatch() {
    delete _computeContext;
    delete _drawContext;

    delete _vertexBuffer;
    delete _varyingBuffer;
}

template <typename VERTEX_BUFFER, typename DRAW_CONTEXT, typename COMPUTE_CONTROLLER> void
OsdUtilMeshBatch<VERTEX_BUFFER, DRAW_CONTEXT, COMPUTE_CONTROLLER>::InitializeVertexBuffers(int numVertexElements, int numVaryingElements) {

    delete _vertexBuffer;
    delete _varyingBuffer;
    delete _drawContext;

    int numVerts = Base::_GetFarMesh()->GetNumVertices();
    _vertexBuffer = numVertexElements ? VertexBuffer::Create(numVertexElements, numVerts) : NULL;
    _varyingBuffer = numVaryingElements ? VertexBuffer::Create(numVaryingElements, numVerts) : NULL;
    _drawContext = DrawContext::Create(Base::_GetFarMesh(), _vertexBuffer, /*fvar=*/false);
    assert(_drawContext);

    // update patch arrays
    Base::updatePatchArrays(numVertexElements);
}

}  // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

}  // end namespace OpenSubdiv

#endif  /* OSD_UTIL_MESH_BATCH_H */