sphereMeshGenerator.h

//
// Copyright 2022 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_GEOM_UTIL_SPHERE_MESH_GENERATOR_H
#define PXR_IMAGING_GEOM_UTIL_SPHERE_MESH_GENERATOR_H

#include "pxr/imaging/geomUtil/api.h"
#include "pxr/imaging/geomUtil/meshGeneratorBase.h"
#include "pxr/imaging/geomUtil/tokens.h"

#include "pxr/pxr.h"

PXR_NAMESPACE_OPEN_SCOPE

class GfMatrix4d;
class PxOsdMeshTopology;

class GeomUtilSphereMeshGenerator final
    : public GeomUtilMeshGeneratorBase
{
public:
    static constexpr size_t minNumRadial = 3;
    static constexpr size_t minNumAxial = 2;

    GEOMUTIL_API
    static size_t ComputeNumPoints(
        const size_t numRadial,
        const size_t numAxial,
        const bool closedSweep = true);

    static size_t ComputeNumNormals(
        const size_t numRadial,
        const size_t numAxial,
        const bool closedSweep = true)
    {
        // Normals are per point.
        return ComputeNumPoints(numRadial, numAxial, closedSweep);
    }

    static TfToken GetNormalsInterpolation()
    {
        // Normals are per point.
        return GeomUtilInterpolationTokens->vertex;
    }

    GEOMUTIL_API
    static PxOsdMeshTopology GenerateTopology(
        const size_t numRadial,
        const size_t numAxial,
        const bool closedSweep = true);

    template<typename PointIterType,
             typename ScalarType,
             typename Enabled =
                typename _EnableIfGfVec3Iterator<PointIterType>::type>
    static void GeneratePoints(
        PointIterType iter,
        const size_t numRadial,
        const size_t numAxial,
        const ScalarType radius,
        const GfMatrix4d* framePtr = nullptr)
    {
        constexpr ScalarType sweep = 360;
        GeneratePoints(iter, numRadial, numAxial, radius, sweep, framePtr);
    }

    template<typename PointIterType,
             typename ScalarType,
             typename Enabled =
                typename _EnableIfGfVec3Iterator<PointIterType>::type>
    static void GeneratePoints(
        PointIterType iter,
        const size_t numRadial,
        const size_t numAxial,
        const ScalarType radius,
        const ScalarType sweepDegrees,
        const GfMatrix4d* framePtr = nullptr)
    {
        using PointType =
            typename std::iterator_traits<PointIterType>::value_type;

        _GeneratePointsImpl(numRadial, numAxial, radius, sweepDegrees,
            framePtr ? _PointWriter<PointType>(iter, framePtr)
                     : _PointWriter<PointType>(iter));
    }

    using GeomUtilMeshGeneratorBase::GeneratePoints;

    template<typename PointIterType,
             typename Enabled =
                typename _EnableIfGfVec3Iterator<PointIterType>::type>
    static void GenerateNormals(
        PointIterType iter,
        const size_t numRadial,
        const size_t numAxial,
        const GfMatrix4d* framePtr = nullptr)
    {
        using PointType =
            typename std::iterator_traits<PointIterType>::value_type;

        constexpr typename PointType::ScalarType sweep = 360;
        GenerateNormals(iter, numRadial, numAxial, sweep, framePtr);
    }

    template<typename PointIterType,
             typename ScalarType,
             typename Enabled =
                typename _EnableIfGfVec3Iterator<PointIterType>::type>
    static void GenerateNormals(
        PointIterType iter,
        const size_t numRadial,
        const size_t numAxial,
        const ScalarType sweepDegrees,
        const GfMatrix4d* framePtr = nullptr)
    {
        using PointType =
            typename std::iterator_traits<PointIterType>::value_type;

        _GenerateNormalsImpl(numRadial, numAxial, sweepDegrees,
            framePtr ? _PointWriter<PointType>(iter, framePtr)
                     : _PointWriter<PointType>(iter));
    }

    using GeomUtilMeshGeneratorBase::GenerateNormals;

private:

    template<typename PointType>
    static void _GeneratePointsImpl(
        const size_t numRadial,
        const size_t numAxial,
        const typename PointType::ScalarType radius,
        const typename PointType::ScalarType sweepDegrees,
        const _PointWriter<PointType>& ptWriter);

    template<typename PointType>
    static void _GenerateNormalsImpl(
        const size_t numRadial,
        const size_t numAxial,
        const typename PointType::ScalarType sweepDegrees,
        const _PointWriter<PointType>& ptWriter);
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_IMAGING_GEOM_UTIL_SPHERE_MESH_GENERATOR_H