DubinsMotionValidator.h

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/* Author: Jaeyoung Lim */
 
#ifndef OMPL_BASE_SPACES_DUBINS_MOTION_VALIDATOR_
#define OMPL_BASE_SPACES_DUBINS_MOTION_VALIDATOR_
 
#include "ompl/base/SpaceInformation.h"
#include <queue>
 
namespace ompl
{
    namespace base
    {
        template <class Dubins2DStateSpace>
        class DubinsMotionValidator : public MotionValidator
        {
        public:
            DubinsMotionValidator(SpaceInformation *si) : MotionValidator(si)
            {
                defaultSettings();
            }
            DubinsMotionValidator(const SpaceInformationPtr &si) : MotionValidator(si)
            {
                defaultSettings();
            }
            ~DubinsMotionValidator() override = default;
            bool checkMotion(const State *s1, const State *s2) const override
            {
                /* assume motion starts in a valid configuration so s1 is valid */
                if (!si_->isValid(s2))
                    return false;
                auto path = stateSpace_->getPath(s1, s2);
                // if (!path)
                // return false;
 
                bool result = true, firstTime = true;
                int nd = stateSpace_->validSegmentCount(s1, s2);
 
                /* initialize the queue of test positions */
                std::queue<std::pair<int, int>> pos;
                if (nd >= 2)
                {
                    pos.emplace(1, nd - 1);
 
                    /* temporary storage for the checked state */
                    State *test = si_->allocState();
 
                    /* repeatedly subdivide the path segment in the middle (and check the middle) */
                    while (!pos.empty())
                    {
                        std::pair<int, int> x = pos.front();
 
                        int mid = (x.first + x.second) / 2;
                        stateSpace_->interpolate(s1, s2, (double)mid / (double)nd, firstTime, path, test);
 
                        if (!si_->isValid(test))
                        {
                            result = false;
                            break;
                        }
 
                        pos.pop();
 
                        if (x.first < mid)
                            pos.emplace(x.first, mid - 1);
                        if (x.second > mid)
                            pos.emplace(mid + 1, x.second);
                    }
 
                    si_->freeState(test);
                }
 
                if (result)
                    valid_++;
                else
                    invalid_++;
 
                return result;
            }
 
            bool checkMotion(const State *s1, const State *s2, std::pair<State *, double> &lastValid) const override
            {
                /* assume motion starts in a valid configuration so s1 is valid */
 
                auto path = stateSpace_->getPath(s1, s2);
                // if (!path)
                // return false;
 
                bool result = true, firstTime = true;
                int nd = stateSpace_->validSegmentCount(s1, s2);
 
                if (nd > 1)
                {
                    /* temporary storage for the checked state */
                    State *test = si_->allocState();
 
                    for (int j = 1; j < nd; ++j)
                    {
                        stateSpace_->interpolate(s1, s2, (double)j / (double)nd, firstTime, path, test);
                        if (!si_->isValid(test))
                        {
                            lastValid.second = (double)(j - 1) / (double)nd;
                            if (lastValid.first != nullptr)
                                stateSpace_->interpolate(s1, s2, lastValid.second, firstTime, path, lastValid.first);
                            result = false;
                            break;
                        }
                    }
                    si_->freeState(test);
                }
 
                if (result)
                    if (!si_->isValid(s2))
                    {
                        lastValid.second = (double)(nd - 1) / (double)nd;
                        if (lastValid.first != nullptr)
                            stateSpace_->interpolate(s1, s2, lastValid.second, firstTime, path, lastValid.first);
                        result = false;
                    }
 
                if (result)
                    valid_++;
                else
                    invalid_++;
 
                return result;
            }
 
        private:
            Dubins2DStateSpace *stateSpace_;
            void defaultSettings()
            {
                stateSpace_ = dynamic_cast<Dubins2DStateSpace *>(si_->getStateSpace().get());
                if (stateSpace_ == nullptr)
                    throw Exception("No state space for motion validator");
            }
        };
    }  // namespace base
}  // namespace ompl
 
#endif