//
// Copyright 2016 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 PXR_IMAGING_HD_SMOOTH_NORMALS_H
#define PXR_IMAGING_HD_SMOOTH_NORMALS_H

#include "pxr/pxr.h"
#include "pxr/imaging/hd/api.h"
#include "pxr/imaging/hd/version.h"
#include "pxr/imaging/hd/bufferSource.h"
#include "pxr/imaging/hd/computation.h"
#include "pxr/imaging/hd/types.h"

#include "pxr/base/gf/vec3d.h"
#include "pxr/base/gf/vec3f.h"
#include "pxr/base/tf/token.h"

PXR_NAMESPACE_OPEN_SCOPE


class Hd_VertexAdjacency;

/// \class Hd_SmoothNormals
///
/// Hd_SmoothNormals encapsulates mesh smooth normals information.
/// It uses passed-in adjacency information and points data to compute
/// smooth per-vertex normals.  It does this by averaging face normals of
/// faces surrounding a vertex.
///
class Hd_SmoothNormals final {
public:
    /// Computes the smooth normals result using the supplied adjacency
    /// information and points data. Returns an array of the same size and
    /// type as the source points, with optional packing.
    HD_API
    static VtArray<GfVec3f> ComputeSmoothNormals(
                                          Hd_VertexAdjacency const * adjacency,
                                          int numPoints,
                                          GfVec3f const * pointsPtr);
    HD_API
    static VtArray<GfVec3d> ComputeSmoothNormals(
                                          Hd_VertexAdjacency const * adjacency,
                                          int numPoints,
                                          GfVec3d const * pointsPtr);
    HD_API
    static VtArray<HdVec4f_2_10_10_10_REV> ComputeSmoothNormalsPacked(
                                          Hd_VertexAdjacency const * adjacency,
                                          int numPoints,
                                          GfVec3f const * pointsPtr);
    HD_API
    static VtArray<HdVec4f_2_10_10_10_REV> ComputeSmoothNormalsPacked(
                                          Hd_VertexAdjacency const * adjacency,
                                          int numPoints,
                                          GfVec3d const * pointsPtr);

private:
    Hd_SmoothNormals() = delete;
    ~Hd_SmoothNormals() = delete;
};

/// \class Hd_SmoothNormalsComputation
///
/// Smooth normal computation CPU.
///
class Hd_SmoothNormalsComputation : public HdComputedBufferSource {
public:
    HD_API
    Hd_SmoothNormalsComputation(Hd_VertexAdjacency const *adjacency,
                                HdBufferSourceSharedPtr const &points,
                                TfToken const &dstName,
                                HdBufferSourceSharedPtr const &adjacencyBuilder,
                                bool packed);

    /// overrides
    HD_API
    virtual void GetBufferSpecs(HdBufferSpecVector *specs) const override;
    HD_API
    virtual bool Resolve() override;
    HD_API
    virtual TfToken const &GetName() const override;

protected:
    HD_API
    virtual bool _CheckValid() const override;

private:
    Hd_VertexAdjacency const *_adjacency;
    HdBufferSourceSharedPtr _points;
    TfToken _dstName;
    HdBufferSourceSharedPtr _adjacencyBuilder;
    bool _packed;
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_IMAGING_HD_SMOOTH_NORMALS_H