ConstrainedSpaceInformation.h

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/* Author: Zachary Kingston */
 
#ifndef OMPL_BASE_CONSTRAINED_SPACE_INFORMATION_
#define OMPL_BASE_CONSTRAINED_SPACE_INFORMATION_
 
#include <utility>
 
#include "ompl/base/SpaceInformation.h"
#include "ompl/base/spaces/constraint/ConstrainedStateSpace.h"
#include "ompl/base/spaces/constraint/AtlasChart.h"
#include "ompl/base/spaces/constraint/AtlasStateSpace.h"
#include "ompl/base/spaces/constraint/TangentBundleStateSpace.h"
 
#include "ompl/util/ClassForward.h"
#include "ompl/util/Console.h"
#include "ompl/util/Exception.h"
 
namespace ompl
{
    namespace base
    {

        OMPL_CLASS_FORWARD(ConstrainedSpaceInformation);

        class ConstrainedValidStateSampler : public ValidStateSampler
        {
        public:
            ConstrainedValidStateSampler(const SpaceInformation *si)
              : ValidStateSampler(si)
              , sampler_(si->getStateSpace()->allocStateSampler())
              , constraint_(si->getStateSpace()->as<ompl::base::ConstrainedStateSpace>()->getConstraint())
            {
            }
 
            bool sample(State *state) override
            {
                // Rejection sample for at most attempts_ tries.
                unsigned int tries = 0;
                bool valid;
 
                do
                    sampler_->sampleUniform(state);
                while (!(valid = si_->isValid(state) && constraint_->isSatisfied(state)) && ++tries < attempts_);
 
                return valid;
            }
 
            bool sampleNear(State *state, const State *near, double distance) override
            {
                // Rejection sample for at most attempts_ tries.
                unsigned int tries = 0;
                bool valid;
                do
                    sampler_->sampleUniformNear(state, near, distance);
                while (!(valid = si_->isValid(state) && constraint_->isSatisfied(state)) && ++tries < attempts_);
 
                return valid;
            }
 
        private:
            StateSamplerPtr sampler_;

            const ConstraintPtr constraint_;
        };

        class ConstrainedSpaceInformation : public SpaceInformation
        {
        public:
            ConstrainedSpaceInformation(StateSpacePtr space) : SpaceInformation(std::move(space))
            {
                stateSpace_->as<ConstrainedStateSpace>()->setSpaceInformation(this);
                setValidStateSamplerAllocator([](const SpaceInformation *si) -> std::shared_ptr<ValidStateSampler>
                                              { return std::make_shared<ConstrainedValidStateSampler>(si); });
            }

            unsigned int getMotionStates(const State *s1, const State *s2, std::vector<State *> &states,
                                         unsigned int /*count*/, bool endpoints, bool /*alloc*/) const override
            {
                bool success = stateSpace_->as<ConstrainedStateSpace>()->discreteGeodesic(s1, s2, true, &states);
 
                if (endpoints)
                {
                    if (!success && states.empty())
                        states.push_back(cloneState(s1));
 
                    if (success)
                        states.push_back(cloneState(s2));
                }
 
                return states.size();
            }
        };

        class TangentBundleSpaceInformation : public ConstrainedSpaceInformation
        {
        public:
            TangentBundleSpaceInformation(StateSpacePtr space) : ConstrainedSpaceInformation(std::move(space))
            {
            }

            unsigned int getMotionStates(const State *s1, const State *s2, std::vector<State *> &states,
                                         unsigned int /*count*/, bool /*endpoints*/, bool /*alloc*/) const override
            {
                auto &&atlas = stateSpace_->as<TangentBundleStateSpace>();
 
                std::vector<State *> temp;
                bool success = atlas->discreteGeodesic(s1, s2, true, &temp);
 
                if (!success && temp.empty())
                    temp.push_back(cloneState(s1));
 
                auto it = temp.begin();
                for (; it != temp.end(); ++it)
                {
                    auto astate = (*it)->as<AtlasStateSpace::StateType>();
                    if (!atlas->project(astate))
                        break;
 
                    states.push_back(astate);
                }
 
                while (it != temp.end())
                    freeState(*it++);
 
                return states.size();
            }

            bool checkMotion(const State *s1, const State *s2, std::pair<State *, double> &lastValid) const override
            {
                auto &&atlas = stateSpace_->as<TangentBundleStateSpace>();
                bool valid = motionValidator_->checkMotion(s1, s2, lastValid);
 
                if (lastValid.first != nullptr)
                {
                    auto astate = lastValid.first->as<AtlasStateSpace::StateType>();
                    if (!atlas->project(astate))
                        valid = false;
                }
 
                return valid;
            }
        };
    }  // namespace base
}  // namespace ompl
 
#endif