MRViewer/MRVectorTraits.h

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#pragma once
 
#include "MRMesh/MRVectorTraits.h"
 
struct ImVec2;
struct ImVec4;
 
namespace MR
{
 
template <>
struct VectorTraits<ImVec2>
{
    using BaseType = float;
    static constexpr int size = 2;
 
    // Can't change the element type...
    template <std::same_as<float>>
    using ChangeBaseType = ImVec2;
 
    template <typename U>
    [[nodiscard]] static auto&& getElem( int i, U&& value )
    {
        // Technically UB, but helps with optimizations on MSVC for some reason, compared to an if-else chain.
        // GCC and Clang optimize both in the same manner.
        return ( &value.x )[i];
    }
 
    template <typename U = ImVec2> // Adding a template parameter to avoid including the whole `imgui.h`.
    static constexpr U diagonal( float v ) { return U( v, v ); }
};
 
template <>
struct VectorTraits<ImVec4>
{
    using BaseType = float;
    static constexpr int size = 4;
 
    // Can't change the element type...
    template <std::same_as<float>>
    using ChangeBaseType = ImVec4;
 
    template <typename U>
    [[nodiscard]] static auto&& getElem( int i, U&& value )
    {
        // Technically UB, but helps with optimizations on MSVC for some reason, compared to an if-else chain.
        // GCC and Clang optimize both in the same manner.
        return ( &value.x )[i];
    }
 
    template <typename U = ImVec4> // Adding a template parameter to avoid including the whole `imgui.h`.
    static constexpr U diagonal( float v ) { return U( v, v, v, v ); }
};
 
}