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Indoor/grid/walk/GridWalkRandomHeadingUpdate.h

101 lines
2.7 KiB
C++

#ifndef GRIDWALKRANDOMHEADINGUPDATE_H
#define GRIDWALKRANDOMHEADINGUPDATE_H
#include "../../geo/Heading.h"
#include "../Grid.h"
#include "../../math/Random.h"
#include "../../nav/dijkstra/Dijkstra.h"
#include "GridWalk.h"
#include "GridWalkState.h"
#include "GridWalkHelper.h"
/**
* for every walked edge: slightly update (scatter) the current heading
* pick the edge (neighbor) best matching the current heading
* if this neighbor's heading highly differs from the requested heading: start over
*
* PROs
* - very simple
*
* CONs
* - particles are bad at walking out of rooms for small grid sizes as there are too many options
* to stay within the room..
*
*/
template <typename T> class GridWalkRandomHeadingUpdate : public GridWalk<T> {
friend class GridWalkHelper;
private:
/** per-edge: change heading with this sigma */
static constexpr float HEADING_CHANGE_SIGMA = Angle::degToRad(10);
/** fast random-number-generator */
Random::RandomGenerator gen;
/** 0-mean normal distribution */
std::normal_distribution<float> headingChangeDist = std::normal_distribution<float>(0.0, HEADING_CHANGE_SIGMA);
public:
/** ctor */
GridWalkRandomHeadingUpdate() {
gen.seed(1234);
}
GridWalkState<T> getDestination(Grid<T>& grid, const GridWalkState<T>& start, const float distance_m, const float headChange_rad, Activity act) override {
return GridWalkHelper::retryOrInvert(*this, 2, grid, start, distance_m, -1);
}
private:
GridWalkState<T> walk(Grid<T>& grid, const GridWalkState<T>& cur, float distRest_m, float headChange = -1) {
// create a copy (to keep heading and walked distance)
GridWalkState<T> next = cur;
// change the heading at the beginning of each walk
if (headChange == -1) {headChange = headingChangeDist(gen);}
// get a new random heading
next.heading = cur.heading + headChange;
// pick the neighbor best matching this new heading
next.node = &GridWalkHelper::getBestNeighbor(grid, *cur.node, next.heading);
// if the best matching neighbor is far of this requested heading
// (e.g. no good neighbor due to walls) cancel the walk. to force a retry
const float diff = GridWalkHelper::getHeading(*cur.node, *next.node).getDiffHalfRAD(next.heading);
if (diff > Angle::degToRad(45)) {
return GridWalkState<T>();
}
// get the distance up to this neighbor
const float walked_m = next.node->getDistanceInMeter(*cur.node);
distRest_m -= walked_m;
// update the heading-change and walked-distance
next.headingChange_rad += next.heading.getRAD() - cur.heading.getRAD();
next.distanceWalked_m += walked_m;
// done?
if (distRest_m <= 0) {return next;}
// another round..
return walk(grid, next, distRest_m, headChange);
}
};
#endif // GRIDWALKRANDOMHEADINGUPDATE_H