sphere.h

#pragma once
 
/* <editor-fold desc="MIT License">
 
Copyright(c) 2018 Robert Osfield
 
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
</editor-fold> */
 
// we can't implement the anonymous union/structs combination without causing warnings, so disable them for just this header
#if defined(__GNUC__)
#    pragma GCC diagnostic push
#    pragma GCC diagnostic ignored "-Wpedantic"
#endif
#if defined(__clang__)
#    pragma clang diagnostic push
#    pragma clang diagnostic ignored "-Wgnu-anonymous-struct"
#    pragma clang diagnostic ignored "-Wnested-anon-types"
#endif
 
#include <vsg/maths/vec3.h>
#include <vsg/maths/vec4.h>
 
namespace vsg
{
    template<typename T>
    struct t_sphere
    {
        using value_type = T;
        using vec_type = t_vec4<T>;
        using center_type = t_vec3<T>;
 
        union
        {
            value_type value[4];
 
            vec_type vec;
 
            struct
            {
                value_type x, y, z, r;
            };
 
            struct
            {
                center_type center;
                value_type radius;
            };
        };
 
        constexpr t_sphere() :
            value{0.0, 0.0, 0.0, -1.0} {}
 
        constexpr t_sphere(const t_sphere& s) :
            value{s[0], s[1], s[2], s[3]} {}
 
        constexpr t_sphere& operator=(const t_sphere&) = default;
 
        template<typename R>
        constexpr explicit t_sphere(const t_sphere<R>& s) :
            value{static_cast<value_type>(s[0]), static_cast<value_type>(s[1]), static_cast<value_type>(s[2]), static_cast<value_type>(s[3])} {}
 
        template<typename R>
        constexpr t_sphere(const t_vec3<R>& c, T rad) :
            value{static_cast<value_type>(c.x), static_cast<value_type>(c.y), static_cast<value_type>(c.z), rad} {}
 
        template<typename R>
        constexpr t_sphere(R sx, R sy, R sz, R sd) :
            value{sx, sy, sz, sd} {}
 
        constexpr std::size_t size() const { return 4; }
 
        value_type& operator[](std::size_t i) { return value[i]; }
        value_type operator[](std::size_t i) const { return value[i]; }
 
        template<typename R>
        t_sphere& operator=(const t_sphere<R>& rhs)
        {
            value[0] = static_cast<value_type>(rhs[0]);
            value[1] = static_cast<value_type>(rhs[1]);
            value[2] = static_cast<value_type>(rhs[2]);
            value[3] = static_cast<value_type>(rhs[3]);
            return *this;
        }
 
        void set(value_type in_x, value_type in_y, value_type in_z, value_type in_r)
        {
            x = in_x;
            y = in_y;
            z = in_z;
            r = in_r;
        }
 
        template<typename R>
        void set(const t_vec3<R>& c, T rad)
        {
            x = static_cast<value_type>(c.x);
            y = static_cast<value_type>(c.y);
            z = static_cast<value_type>(c.z);
            r = rad;
        }
 
        bool valid() const { return radius >= 0.0; }
 
        explicit operator bool() const noexcept { return valid(); }
 
        T* data() { return value; }
        const T* data() const { return value; }
 
        void reset()
        {
            center.set(0.0, 0.0, 0.0);
            radius = -1.0;
        }
    };
 
    using sphere = t_sphere<float>;   
    using dsphere = t_sphere<double>; 
 
    VSG_type_name(vsg::sphere);
    VSG_type_name(vsg::dsphere);
 
    template<typename T>
    constexpr bool operator==(const t_sphere<T>& lhs, const t_sphere<T>& rhs)
    {
        return (lhs.center == rhs.center) && (lhs.radius == rhs.radius);
    }
 
    template<typename T>
    constexpr bool operator!=(const t_sphere<T>& lhs, const t_sphere<T>& rhs)
    {
        return (lhs.center != rhs.center) || (lhs.radius != rhs.radius);
    }
 
    template<typename T>
    constexpr bool operator<(const t_sphere<T>& lhs, const t_sphere<T>& rhs)
    {
        if (lhs.center < rhs.center) return true;
        if (rhs.center < lhs.center) return false;
        return lhs.radius < rhs.radius;
    }
 
} // namespace vsg
 
#if defined(__clang__)
#    pragma clang diagnostic pop
#endif
#if defined(__GNUC__)
#    pragma GCC diagnostic pop
#endif