triangle_bit_flags.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
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 * This program is distributed in the hope that it will be useful,           *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_MESH_COMPONENTS_TRIANGLE_BIT_FLAGS_H
#define VCL_MESH_COMPONENTS_TRIANGLE_BIT_FLAGS_H
 
#include "bases/component.h"
 
#include <vclib/concepts/mesh/components/bit_flags.h>
#include <vclib/space/core/bit_set.h>
 
namespace vcl::comp {
 
template<typename ParentElemType = void, bool OPT = false>
class TriangleBitFlags :
        public Component<
            TriangleBitFlags<ParentElemType, OPT>,
            CompId::BIT_FLAGS,
            BitSet<short>,
            ParentElemType,
            !std::is_same_v<ParentElemType, void>,
            OPT>
{
    using Base = Component<
        TriangleBitFlags<ParentElemType, OPT>,
        CompId::BIT_FLAGS,
        BitSet<short>,
        ParentElemType,
        !std::is_same_v<ParentElemType, void>,
        OPT>;
 
    using FT = short; // FlagsType, the integral type used for the flags
 
    static const uint FIRST_USER_BIT = 15;
 
    // indices of the bits
    enum {
        DELETED  = 0, // bit 0
        SELECTED = 1, // bit 1
        VISITED  = 2, // bit 2
        // Edge border
        BORDER0 = 3, // bits [3, 5]
        // Edge selection
        EDGESEL0 = 6, // bits [6, 8]
        EDGEVIS0 = 9, // bits [9, 11]
        // Faux edges: when representing polygonal meshes on triangle meshes,
        // some triangle edges can be marked as "faux", meaning that they are
        // internal on the polygon
        FAUX0 = 12 // bits [12, 14]
    };
 
public:
    inline static const uint USER_BITS_NUMBER = sizeof(FT) * 8 - FIRST_USER_BIT;
 
    /* Constructors */
 
    TriangleBitFlags()
    {
        if constexpr (!Base::IS_VERTICAL) {
            init();
        }
    }
 
    void init() { flags().reset(); }
 
    /* Member functions */
 
    bool deleted() const { return flags()[DELETED]; }
 
    BitProxy<FT> selected() { return flags()[SELECTED]; }
 
    bool selected() const { return flags()[SELECTED]; }
 
    BitProxy<FT> visited() { return flags()[VISITED]; }
 
    bool visited() const { return flags()[VISITED]; }
 
    bool onBorder() const
    {
        return edgeOnBorder(0) || edgeOnBorder(1) || edgeOnBorder(2);
    }
 
    BitProxy<FT> edgeOnBorder(uint i)
    {
        assert(i < 3);
        return flags()[BORDER0 + i];
    }
 
    bool edgeOnBorder(uint i) const
    {
        assert(i < 3);
        return flags()[BORDER0 + i];
    }
 
    BitProxy<FT> edgeSelected(uint i)
    {
        assert(i < 3);
        return flags()[EDGESEL0 + i];
    }
 
    bool edgeSelected(uint i) const
    {
        assert(i < 3);
        return flags()[EDGESEL0 + i];
    }
 
    BitProxy<FT> edgeVisited(uint i)
    {
        assert(i < 3);
        return flags()[EDGEVIS0 + i];
    }
 
    bool edgeVisited(uint i) const
    {
        assert(i < 3);
        return flags()[EDGEVIS0 + i];
    }
 
    BitProxy<FT> edgeFaux(uint i)
    {
        assert(i < 3);
        return flags()[FAUX0 + i];
    }
 
    bool edgeFaux(uint i) const
    {
        assert(i < 3);
        return flags()[FAUX0 + i];
    }
 
    bool userBit(uint bit) const
    {
        assert(bit < USER_BITS_NUMBER);
        return flags()[bit + FIRST_USER_BIT];
    }
 
    BitProxy<FT> userBit(uint bit)
    {
        assert(bit < USER_BITS_NUMBER);
        return flags()[bit + FIRST_USER_BIT];
    }
 
    void resetBitFlags()
    {
        bool isD = deleted();
        flags().reset();
        deletedBit() = isD;
    }
 
    void importFlagsFromVCGFormat(int f)
    {
        if (f & 0x00000010)
            visited() = true;
        if (f & 0x00000020)
            selected() = true;
        if (f & 0x00000040)
            edgeOnBorder(0) = true;
        if (f & 0x00000080)
            edgeOnBorder(1) = true;
        if (f & 0x00000100)
            edgeOnBorder(2) = true;
        if (f & 0x00008000)
            edgeSelected(0) = true;
        if (f & 0x00010000)
            edgeSelected(1) = true;
        if (f & 0x00020000)
            edgeSelected(2) = true;
        if (f & 0x00040000)
            edgeFaux(0) = true;
        if (f & 0x00080000)
            edgeFaux(1) = true;
        if (f & 0x00100000)
            edgeFaux(2) = true;
    }
 
    int exportFlagsToVCGFormat() const
    {
        int f = 0;
        if (visited())
            f &= 0x00000010;
        if (selected())
            f &= 0x00000020;
        if (edgeOnBorder(0))
            f &= 0x00000040;
        if (edgeOnBorder(1))
            f &= 0x00000080;
        if (edgeOnBorder(2))
            f &= 0x00000100;
        if (edgeSelected(0))
            f &= 0x00008000;
        if (edgeSelected(1))
            f &= 0x00010000;
        if (edgeSelected(2))
            f &= 0x00020000;
        if (edgeFaux(0))
            f &= 0x00040000;
        if (edgeFaux(1))
            f &= 0x00080000;
        if (edgeFaux(2))
            f &= 0x00100000;
        return f;
    }
 
    // dummy member to discriminate between triangle and non-triangle bit flags
    void __triangleBitFlags() const {}
 
protected:
    BitProxy<FT> deletedBit() { return flags()[DELETED]; }
 
    // Component interface functions
    template<typename Element>
    void importFrom(const Element& e, bool = true)
    {
        if constexpr (HasBitFlags<Element>) {
            resetBitFlags();
            if constexpr (HasTriangleBitFlags<Element>) {
                flags() = e.flags();
            }
            else {
                // BitFlags
                deletedBit()  = e.deleted();
                selected()    = e.selected();
                visited()     = e.visited();
                const uint UM = std::min(USER_BITS_NUMBER, e.USER_BITS_NUMBER);
                for (uint i = 0; i < UM; ++i)
                    userBit(i) = e.userBit(i);
                if constexpr (HasPolygonBitFlags<Element>) {
                    // PolygonBitFlags
                    for (uint i = 0; i < 3; ++i) {
                        edgeOnBorder(i) = e.edgeOnBorder(i);
                        edgeSelected(i) = e.edgeSelected(i);
                        edgeFaux(i)     = e.edgeFaux(i);
                    }
                }
            }
        }
    }
 
    void serialize(std::ostream& os) const { flags().serialize(os); }
 
    void deserialize(std::istream& is) { flags().deserialize(is); }
 
private:
    // members that allow to access the flags, trough data (horizontal) or
    // trough parent (vertical)
    BitSet<FT>& flags() { return Base::data(); }
 
    BitSet<FT> flags() const { return Base::data(); }
};
 
} // namespace vcl::comp
 
#endif // VCL_MESH_COMPONENTS_TRIANGLE_BIT_FLAGS_H