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#include <mbgl/util/grid_index.hpp>
#include <mbgl/geometry/feature_index.hpp>
#include <mbgl/math/minmax.hpp>
#include <unordered_set>
#include <cmath>
namespace mbgl {
template <class T>
GridIndex<T>::GridIndex(int32_t width_, int32_t height_, int32_t cellSize_) :
width(width_),
height(height_),
xCellCount(std::ceil(float(width_) / cellSize_)),
yCellCount(std::ceil(float(height_) / cellSize_)),
xScale(float(xCellCount) / width_),
yScale(float(yCellCount) / height_)
{
boxCells.resize(xCellCount * yCellCount);
circleCells.resize(xCellCount * yCellCount);
}
template <class T>
void GridIndex<T>::insert(T&& t, const BBox& bbox) {
size_t uid = boxElements.size();
auto cx1 = convertToXCellCoord(bbox.min.x);
auto cy1 = convertToYCellCoord(bbox.min.y);
auto cx2 = convertToXCellCoord(bbox.max.x);
auto cy2 = convertToYCellCoord(bbox.max.y);
int32_t x, y, cellIndex;
for (x = cx1; x <= cx2; ++x) {
for (y = cy1; y <= cy2; ++y) {
cellIndex = xCellCount * y + x;
boxCells[cellIndex].push_back(uid);
}
}
boxElements.emplace_back(t, bbox);
}
template <class T>
void GridIndex<T>::insert(T&& t, const BCircle& bcircle) {
size_t uid = circleElements.size();
auto cx1 = convertToXCellCoord(bcircle.center.x - bcircle.radius);
auto cy1 = convertToYCellCoord(bcircle.center.y - bcircle.radius);
auto cx2 = convertToXCellCoord(bcircle.center.x + bcircle.radius);
auto cy2 = convertToYCellCoord(bcircle.center.y + bcircle.radius);
int32_t x, y, cellIndex;
for (x = cx1; x <= cx2; ++x) {
for (y = cy1; y <= cy2; ++y) {
cellIndex = xCellCount * y + x;
circleCells[cellIndex].push_back(uid);
}
}
circleElements.emplace_back(t, bcircle);
}
template <class T>
std::vector<T> GridIndex<T>::query(const BBox& queryBBox) const {
std::vector<T> result;
query(queryBBox, [&](const T& t) -> bool {
result.push_back(t);
return false;
});
return result;
}
// TODO: templatize this on geometry type
template <class T>
std::vector<T> GridIndex<T>::query(const BCircle& queryBCircle) const {
std::vector<T> result;
query(queryBCircle, [&](const T& t) -> bool {
result.push_back(t);
return false;
});
return result;
}
template <class T>
bool GridIndex<T>::hitTest(const BBox& queryBBox) const {
bool hit = false;
query(queryBBox, [&](const T&) -> bool {
hit = true;
return true;
});
return hit;
}
// TODO: templatize this on geometry type
template <class T>
bool GridIndex<T>::hitTest(const BCircle& queryBCircle) const {
bool hit = false;
query(queryBCircle, [&](const T&) -> bool {
hit = true;
return true;
});
return hit;
}
template <class T>
void GridIndex<T>::query(const BBox& queryBBox, std::function<bool (const T&)> resultFn) const {
std::unordered_set<size_t> seenBoxes;
std::unordered_set<size_t> seenCircles;
auto cx1 = convertToXCellCoord(queryBBox.min.x);
auto cy1 = convertToYCellCoord(queryBBox.min.y);
auto cx2 = convertToXCellCoord(queryBBox.max.x);
auto cy2 = convertToYCellCoord(queryBBox.max.y);
int32_t x, y, cellIndex;
for (x = cx1; x <= cx2; ++x) {
for (y = cy1; y <= cy2; ++y) {
cellIndex = xCellCount * y + x;
// Look up other boxes
for (auto uid : boxCells[cellIndex]) {
if (seenBoxes.count(uid) == 0) {
seenBoxes.insert(uid);
auto& pair = boxElements.at(uid);
auto& bbox = pair.second;
if (boxesCollide(queryBBox, bbox)) {
if (resultFn(pair.first)) {
return;
}
}
}
}
// Look up circles
for (auto uid : circleCells[cellIndex]) {
if (seenCircles.count(uid) == 0) {
seenCircles.insert(uid);
auto& pair = circleElements.at(uid);
auto& bcircle = pair.second;
if (circleAndBoxCollide(bcircle, queryBBox)) {
if (resultFn(pair.first)) {
return;
}
}
}
}
}
}
}
template <class T>
void GridIndex<T>::query(const BCircle& queryBCircle, std::function<bool (const T&)> resultFn) const {
std::unordered_set<size_t> seenBoxes;
std::unordered_set<size_t> seenCircles;
auto cx1 = convertToXCellCoord(queryBCircle.center.x - queryBCircle.radius);
auto cy1 = convertToYCellCoord(queryBCircle.center.y - queryBCircle.radius);
auto cx2 = convertToXCellCoord(queryBCircle.center.x + queryBCircle.radius);
auto cy2 = convertToYCellCoord(queryBCircle.center.y + queryBCircle.radius);
int32_t x, y, cellIndex;
for (x = cx1; x <= cx2; ++x) {
for (y = cy1; y <= cy2; ++y) {
cellIndex = xCellCount * y + x;
// Look up boxes
for (auto uid : boxCells[cellIndex]) {
if (seenBoxes.count(uid) == 0) {
seenBoxes.insert(uid);
auto& pair = boxElements.at(uid);
auto& bbox = pair.second;
if (circleAndBoxCollide(queryBCircle, bbox)) {
if (resultFn(pair.first)) {
return;
}
}
}
}
// Look up other circles
for (auto uid : circleCells[cellIndex]) {
if (seenCircles.count(uid) == 0) {
seenCircles.insert(uid);
auto& pair = circleElements.at(uid);
auto& bcircle = pair.second;
if (circlesCollide(queryBCircle, bcircle)) {
if (resultFn(pair.first)) {
return;
}
}
}
}
}
}
}
template <class T>
int32_t GridIndex<T>::convertToXCellCoord(int32_t x) const {
return util::max(0.0, util::min(xCellCount - 1.0, std::floor(x * xScale)));
}
template <class T>
int32_t GridIndex<T>::convertToYCellCoord(int32_t y) const {
return util::max(0.0, util::min(yCellCount - 1.0, std::floor(y * yScale)));
}
template <class T>
bool GridIndex<T>::boxesCollide(const BBox& first, const BBox& second) const {
return first.min.x <= second.max.x &&
first.min.y <= second.max.y &&
first.max.x >= second.min.x &&
first.max.y >= second.min.y;
}
template <class T>
bool GridIndex<T>::circlesCollide(const BCircle& first, const BCircle& second) const {
auto dx = second.center.x - first.center.x;
auto dy = second.center.y - first.center.y;
auto bothRadii = first.radius + second.radius;
return (bothRadii * bothRadii) > (dx * dx + dy * dy);
}
template <class T>
bool GridIndex<T>::circleAndBoxCollide(const BCircle& circle, const BBox& box) const {
auto halfRectWidth = (box.max.x - box.min.x) / 2;
auto distX = std::abs(circle.center.x - (box.min.x + halfRectWidth));
if (distX > (halfRectWidth + circle.radius)) {
return false;
}
auto halfRectHeight = (box.max.y - box.min.y) / 2;
auto distY = std::abs(circle.center.y - (box.min.y + halfRectHeight));
if (distY > (halfRectHeight + circle.radius)) {
return false;
}
if (distX <= halfRectWidth || distY <= halfRectHeight) {
return true;
}
auto dx = distX - halfRectWidth;
auto dy = distY - halfRectHeight;
return (dx * dx + dy * dy) <= (circle.radius * circle.radius);
}
template <class T>
bool GridIndex<T>::empty() const {
return boxElements.empty() && circleElements.empty();
}
template class GridIndex<IndexedSubfeature>;
} // namespace mbgl
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