GEO_PrimTriFan.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        GEO_PrimTriFan.h ( GEO Library, C++)
 *
 * COMMENTS: Implements a normal triangle fan.
 */

#ifndef __GEO_PrimTriFan__
#define __GEO_PrimTriFan__

#include "GEO_API.h"
#include "GEO_TriMesh.h"
#include "GEO_PrimType.h"

class GA_Detail;

/// Triangle fan.  All triangles share the first vertex
class GEO_API GEO_PrimTriFan : public GEO_TriMesh
{
protected:
    /// NOTE: The constructor should only be called from subclass
    ///       constructors.
    GEO_PrimTriFan(GA_Detail *d, GA_Offset offset = GA_INVALID_OFFSET)
        : GEO_TriMesh(d, offset)
    {}

    /// NOTE: The destructor should only be called from subclass
    ///       destructors.
    ~GEO_PrimTriFan() override {}

public:
    /// @{
    /// Interface from GEO_TriMesh
    bool        isDegenerate() const override;
    UT_Vector3  computeNormal() const override;
    UT_Vector3D computeNormalD() const override;
    void        reverse() override;

    fpreal      calcVolume(const UT_Vector3 &refpt) const override;
    fpreal      calcArea() const override;
    fpreal      calcPerimeter() const override;
    /// @}

    /// Get number of triangles in the fan
    exint       getTriangleCount() const        { return getVertexCount()-2; }

    /// Get the vertices for a single triangle in the fan
    void        getTriangleVertices(exint tri, int &v0, int &v1, int &v2) const
                {
                    v0 = 0;
                    v1 = tri + 1;
                    v2 = tri + 2;
                }

    const GA_PrimitiveJSON              *getJSON() const override;

protected:
    static GA_PrimitiveFamilyMask       buildFamilyMask()
                            { return GEO_TriMesh::buildFamilyMask(); }

    template <typename T>
    UT_Vector3T<T> internalComputeNormal() const;

    /// All subclasses should call this method to register the curve intrinsics.
    /// @see GA_IntrinsicManager
    static GA_IntrinsicManager::Registrar
                        registerIntrinsics(GA_PrimitiveDefinition &defn)
                            { return GEO_TriMesh::registerIntrinsics(defn); }

    // We don't need to save anything other than what's in a face
    bool                savePrivateH9(std::ostream &,
                                      bool binary) const override;
    bool                loadPrivateH9(UT_IStream &) override;

private:
    friend std::ostream &operator<<(std::ostream &os, const GEO_PrimTriFan &d)
                        {
                            d.saveH9(os, 0,
                                     GEO_Primitive::theEmptySaveAttribs,
                                     GEO_Primitive::theEmptySaveAttribs);
                            return os;
                        }
};

#endif