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Indoor/grid/walk/GridWalkWeighted2.h
kazu 9947dced15 added several grid-walks
added new helper methods/classes (e.g. for heading)
new test cases
optimize the dijkstra
cleanups/refactoring
added timed-benchmarks to the log
many more...
2016-01-24 18:59:06 +01:00

128 lines
3.3 KiB
C++

#ifndef GRIDWALKWEIGHTED2_H
#define GRIDWALKWEIGHTED2_H
#include "../../geo/Heading.h"
#include "../Grid.h"
#include "../../math/DrawList.h"
#include <KLib/math/distribution/Normal.h>
/**
* perform walks on the grid based on some sort of weighting
* and drawing from the weighted elements
*/
template <typename T> class GridWalkWeighted {
public:
struct State {
const T* node;
Heading heading;
State() : node(nullptr), heading(0) {;}
State(const T* node, Heading heading) : node(node), heading(heading) {;}
};
private:
/** per-edge: change heading with this sigma */
static constexpr float HEADING_CHANGE_SIGMA = Angle::degToRad(5);
/** per-edge: allowed heading difference */
static constexpr float HEADING_DIFF_SIGMA = Angle::degToRad(20);
/** allows drawing elements according to their probability */
DrawList<T&> drawer;
/** fast random-number-generator */
std::minstd_rand gen;
/** 0-mean normal distribution */
std::normal_distribution<float> headingChangeDist = std::normal_distribution<float>(0.0, HEADING_CHANGE_SIGMA);
public:
template <int gridSize_cm> State getDestination(Grid<gridSize_cm, T>& grid, State start, float distance_m) {
int retries = 2;
State res;
// try to walk the given distance from the start
// if this fails (reached a dead end) -> restart (maybe the next try finds a better path)
do {
res = walk(grid, start, distance_m);
} while (res.node == nullptr && --retries);
// still reaching a dead end?
// -> try a walk in the opposite direction instead
if (res.node == nullptr) {
res = walk(grid, State(start.node, start.heading.getInverted()), distance_m);
}
// still nothing found? -> keep the start as-is
return (res.node == nullptr) ? (start) : (res);
}
private:
static Heading getHeading(const T& from, const T& to) {
return Heading(from.x_cm, from.y_cm, to.x_cm, to.y_cm);
}
template <int gridSize_cm> State walk(Grid<gridSize_cm, T>& grid, State cur, float distRest_m) {
// make the draw-list empty (faster than allocating a new one every time?)
drawer.reset();
// calculate probabilites for the neighboring nodes
for (T& neighbor : grid.neighbors(*cur.node)) {
// heading when walking from cur to neighbor
Heading potentialHeading(cur.node->x_cm, cur.node->y_cm, neighbor.x_cm, neighbor.y_cm);
// angular difference
const float diff = cur.heading.getDiffHalfRAD(potentialHeading);
// probability for this change?
double prob = K::NormalDistribution::getProbability(0, HEADING_DIFF_SIGMA, diff);
// adjust by the neighbors importance factor
//prob += std::pow(neighbor.impPath, 2);
prob *= neighbor.imp;
//prob *= K::NormalDistribution::getProbability(1.4, 0.2, neighbor.imp);
drawer.add(neighbor, prob);
}
// if there is no likely neighbor at all, we reached a dead end
// -> start over!
if (drawer.getCumProbability() < 0.01) {return State(nullptr, 0);}
// get the next node
T* nn = &drawer.get();
//Heading potentialHeading(cur.node->x_cm, cur.node->y_cm, nn->x_cm, nn->y_cm);
//State next(nn, potentialHeading);
State next(&nn, cur.heading);
next.heading += headingChangeDist(gen);
// get the distance up to this neighbor
distRest_m -= next.node->getDistanceInMeter(*cur.node);
// done?
if (distRest_m <= 0) {return next;}
// another round..
return walk(grid, next, distRest_m);
}
};
#endif // GRIDWALKWEIGHTED2_H