C++ (Cpp) TransformState::cornersToBox Examples

Example #1

File: source.cpp Project: ariosx/mapbox-gl-native

std::forward_list<Tile::ID> Source::coveringTiles(const TransformState& state) const {
    int32_t z = coveringZoomLevel(state);

    if (z < info.min_zoom) return {{}};
    if (z > info.max_zoom) z = info.max_zoom;

    // Map four viewport corners to pixel coordinates
    box points = state.cornersToBox(z);
    const vec2<double>& center = points.center;

    std::forward_list<Tile::ID> covering_tiles = Tile::cover(z, points);

    covering_tiles.sort([&center](const Tile::ID& a, const Tile::ID& b) {
        // Sorts by distance from the box center
        return std::fabs(a.x - center.x) + std::fabs(a.y - center.y) <
               std::fabs(b.x - center.x) + std::fabs(b.y - center.y);
    });

    return covering_tiles;
}