ray.hpp

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 Copyright (c) 2026 ETIB Corporation
 
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#pragma once
 
#include <ostream>
#include <stdexcept>
#include <type_traits>
#include <utility>
#include <ostream>
 
#include "utility/graphic/position.hpp"
 
#include "utility/math/vector.hpp"
 
#include "utility/graphic/mesh.hpp"
 
namespace utility::graphic
{
    template<typename Type>
    concept CanBeRayComponent =
        CanBePositionComponent<Type> && math::CanBeVectorComponent<Type>;
    template<CanBeRayComponent RayComponentType> class Ray
    {
        private:
        protected:
        Position<RayComponentType> _origin;
 
        math::Vector<RayComponentType, 3> _direction;
 
        static void validateDirection(
            const math::Vector<RayComponentType, 3> &direction)
        {
            const RayComponentType squaredLength = direction[0] * direction[0]
                + direction[1] * direction[1] + direction[2] * direction[2];
            if (squaredLength == RayComponentType {}) {
                throw std::invalid_argument("Ray direction must be non-zero");
            }
        }
 
        public:
        Ray(void)
            : _origin()
        {
            _direction    = math::Vector<RayComponentType, 3>();
            _direction[0] = RayComponentType { 1 };
        }
 
        Ray(math::Vector<RayComponentType, 3> origin,
            math::Vector<RayComponentType, 3> direction)
            : _origin(std::move(origin))
            , _direction(std::move(direction))
        {
            validateDirection(_direction);
        }
 
        Ray(const Ray &other)
            : _origin(other._origin)
            , _direction(other._direction)
        {
        }
 
        Ray(Ray &&other) noexcept
            : _origin(std::move(other._origin))
            , _direction(std::move(other._direction))
        {
        }
 
        Ray &operator=(const Ray &other)
        {
            if (this != &other) {
                _origin    = other._origin;
                _direction = other._direction;
            }
            return *this;
        }
 
        Ray &operator=(Ray &&other) noexcept
        {
            if (this != &other) {
                _origin    = std::move(other._origin);
                _direction = std::move(other._direction);
            }
            return *this;
        }
 
        // Destructor
        ~Ray(void) = default;
 
        void setOrigin(const math::Vector<RayComponentType, 3> &origin)
        {
            _origin = Position<RayComponentType>(origin);
        }
 
        void setOrigin(const Position<RayComponentType> &origin)
        {
            _origin = origin;
        }
 
        math::Vector<RayComponentType, 3> getOrigin() const
        {
            return _origin;
        }
 
        void setDirection(const math::Vector<RayComponentType, 3> &direction)
        {
            validateDirection(direction);
            _direction = direction;
        }
 
        math::Vector<RayComponentType, 3> getDirection(void) const
        {
            return _direction;
        }
 
        const Position<RayComponentType> &origin(void) const noexcept
        {
            return _origin;
        }
 
        const math::Vector<RayComponentType, 3> &direction(void) const noexcept
        {
            return _direction;
        }
 
        math::Vector<RayComponentType, 3> normalizedDirection() const
        {
            return math::normalize(_direction);
        }
 
        math::Vector<RayComponentType, 3>
            pointAt(RayComponentType distanceParameter) const
        {
            return _origin + (_direction * distanceParameter);
        }
 
        math::Vector<RayComponentType, 3>
            at(RayComponentType distanceParameter) const
        {
            return pointAt(distanceParameter);
        }
 
        void translate(const math::Vector<RayComponentType, 3> &offset)
        {
            _origin += offset;
        }
 
        Ray translated(const math::Vector<RayComponentType, 3> &offset) const
        {
            return Ray(_origin + offset, _direction);
        }
 
        bool operator==(const Ray &other) const
        {
            return _origin == other._origin && _direction == other._direction;
        }
 
        bool operator!=(const Ray &other) const
        {
            return !(*this == other);
        }
 
        template<typename RectanglePoseType>
        bool intersectRectangle(const RectanglePoseType &rectanglePose,
                                const math::Vector2F &rectangleSize) const
        {
            const auto rectangleOrientation = rectanglePose.getOrientation();
 
            const math::Vector<RayComponentType, 3> right =
                rectangleOrientation.getRight();
            const math::Vector<RayComponentType, 3> up =
                rectangleOrientation.getUp();
            const math::Vector<RayComponentType, 3> planeNormal =
                rectangleOrientation.getForward();
 
            const RayComponentType halfWidth =
                static_cast<RayComponentType>(rectangleSize[0])
                / RayComponentType { 2 };
            const RayComponentType halfHeight =
                static_cast<RayComponentType>(rectangleSize[1])
                / RayComponentType { 2 };
 
            const math::Vector<RayComponentType, 3> topLeft =
                math::Vector<RayComponentType, 3>(rectanglePose.getPosition());
 
            // The rectangle's position is treated as its top-left corner. The
            // center is found by extending half the width along the rectangle's
            // right axis and half the height along its up axis.
            const math::Vector<RayComponentType, 3> rectangleCenter =
                topLeft + right * halfWidth + up * halfHeight;
 
            const RayComponentType denominator =
                math::dot(_direction, planeNormal);
 
            if (denominator == RayComponentType {}) {
                const math::Vector<RayComponentType, 3> toOrigin =
                    math::Vector<RayComponentType, 3>(_origin)
                    - rectangleCenter;
 
                if (math::dot(toOrigin, planeNormal) == RayComponentType {}) {
                    return true;
                }
                return false;
            }
 
            const math::Vector<RayComponentType, 3> toCenter =
                rectangleCenter - math::Vector<RayComponentType, 3>(_origin);
 
            const RayComponentType t =
                math::dot(toCenter, planeNormal) / denominator;
 
            if (t < RayComponentType {}) {
                return false;
            }
 
            const math::Vector<RayComponentType, 3> intersectionPoint =
                pointAt(t);
            const math::Vector<RayComponentType, 3> localPoint =
                intersectionPoint - rectangleCenter;
 
            const RayComponentType rightCoord = math::dot(localPoint, right);
            const RayComponentType upCoord    = math::dot(localPoint, up);
 
            return (rightCoord >= -halfWidth && rightCoord <= halfWidth
                    && upCoord >= -halfHeight && upCoord <= halfHeight);
        }
 
        utility::graphic::Mesh convertToMesh(
            float length, float radius, int segments,
            utility::graphic::Color32Bit color = { 255, 255, 255, 255 }) const
        {
            utility::graphic::Mesh mesh({}, {});
 
            auto dir = utility::math::normalize(_direction);
 
            utility::math::Vector3F up { 0.0f, 1.0f, 0.0f };
 
            // If the ray is almost parallel to Up, choose another axis.
            if (std::abs(utility::math::dot(dir, up)) > 0.99f)
                up = utility::math::Vector3F { 1.0f, 0.0f, 0.0f };
 
            auto right =
                utility::math::normalize(utility::math::cross(dir, up));
            auto realUp = utility::math::cross(right, dir);
 
            utility::math::Vector3F start = _origin;
            utility::math::Vector3F end   = start + dir * length;
 
            for (int i = 0; i < segments; ++i) {
                float a0 = 2.0f * M_PI * i / segments;
                float a1 = 2.0f * M_PI * (i + 1) / segments;
 
                auto offset0 = right * (std::cos(a0) * radius)
                    + realUp * (std::sin(a0) * radius);
 
                auto offset1 = right * (std::cos(a1) * radius)
                    + realUp * (std::sin(a1) * radius);
 
                uint32_t base =
                    static_cast<uint32_t>(mesh.getVertices().size());
 
                utility::graphic::VertexF vertex;
 
                vertex.setColor(color);
 
                auto p0 = start + offset0;
                auto p1 = start + offset1;
                auto p2 = end + offset0;
                auto p3 = end + offset1;
 
                vertex.setPosition(
                    utility::graphic::PositionF(p0.x, p0.y, p0.z));
                mesh.addVertex(vertex);
 
                vertex.setPosition(
                    utility::graphic::PositionF(p1.x, p1.y, p1.z));
                mesh.addVertex(vertex);
 
                vertex.setPosition(
                    utility::graphic::PositionF(p2.x, p2.y, p2.z));
                mesh.addVertex(vertex);
 
                vertex.setPosition(
                    utility::graphic::PositionF(p3.x, p3.y, p3.z));
                mesh.addVertex(vertex);
 
                mesh.addIndex(base + 0);
                mesh.addIndex(base + 1);
                mesh.addIndex(base + 2);
 
                mesh.addIndex(base + 2);
                mesh.addIndex(base + 1);
                mesh.addIndex(base + 3);
            }
 
            return mesh;
        }
    };
 
    using RayF = Ray<float>;
 
    using RayD = Ray<double>;
 
    std::ostream &operator<<(std::ostream &stream, const RayF &ray);
 
    std::ostream &operator<<(std::ostream &stream, const RayD &ray);
 
}    // namespace utility::graphic