diff options
Diffstat (limited to 'src/mbgl/util/tile_cover.cpp')
| -rw-r--r-- | src/mbgl/util/tile_cover.cpp | 75 |
1 files changed, 68 insertions, 7 deletions
diff --git a/src/mbgl/util/tile_cover.cpp b/src/mbgl/util/tile_cover.cpp index 803aa53eee..e77ea469a7 100644 --- a/src/mbgl/util/tile_cover.cpp +++ b/src/mbgl/util/tile_cover.cpp @@ -1,7 +1,8 @@ #include <mbgl/util/tile_cover.hpp> #include <mbgl/util/vec.hpp> -#include <mbgl/util/box.hpp> #include <mbgl/util/tile_coordinate.hpp> +#include <mbgl/util/constants.hpp> +#include <mbgl/map/transform_state.hpp> namespace mbgl { @@ -66,7 +67,27 @@ static void scanTriangle(const mbgl::vec2<double> a, const mbgl::vec2<double> b, if (bc.dy) scanSpans(ca, bc, ymin, ymax, scanLine); } -std::forward_list<TileID> tileCover(int8_t z, const mbgl::box &bounds, int8_t actualZ) { +int32_t coveringZoomLevel(double zoom, SourceType type, uint16_t tileSize) { + zoom += std::log(util::tileSize / tileSize) / std::log(2); + if (type == SourceType::Raster || type == SourceType::Video) { + return ::round(zoom); + } else { + return std::floor(zoom); + } +} + +static mbgl::vec2<double> zoomTo(const TileCoordinate& c, double z) { + double scale = std::pow(2, z - c.zoom); + return { c.column * scale, c.row * scale }; +} + +std::vector<TileID> tileCover(const TileCoordinate& tl_, + const TileCoordinate& tr_, + const TileCoordinate& br_, + const TileCoordinate& bl_, + const TileCoordinate& center, + int32_t z, + int32_t actualZ) { int32_t tiles = 1 << z; std::forward_list<mbgl::TileID> t; @@ -79,10 +100,11 @@ std::forward_list<TileID> tileCover(int8_t z, const mbgl::box &bounds, int8_t ac } }; - mbgl::vec2<double> tl = { bounds.tl.column, bounds.tl.row }; - mbgl::vec2<double> tr = { bounds.tr.column, bounds.tr.row }; - mbgl::vec2<double> br = { bounds.br.column, bounds.br.row }; - mbgl::vec2<double> bl = { bounds.bl.column, bounds.bl.row }; + mbgl::vec2<double> tl = zoomTo(tl_, z); + mbgl::vec2<double> tr = zoomTo(tr_, z); + mbgl::vec2<double> br = zoomTo(br_, z); + mbgl::vec2<double> bl = zoomTo(bl_, z); + mbgl::vec2<double> c = zoomTo(center, z); // Divide the screen up in two triangles and scan each of them: // \---+ @@ -94,7 +116,46 @@ std::forward_list<TileID> tileCover(int8_t z, const mbgl::box &bounds, int8_t ac t.sort(); t.unique(); - return t; + t.sort([&](const TileID& a, const TileID& b) { + // Sorts by distance from the box center + return std::fabs(a.x - c.x) + std::fabs(a.y - c.y) < + std::fabs(b.x - c.x) + std::fabs(b.y - c.y); + }); + + return std::vector<TileID>(t.begin(), t.end()); +} + +std::vector<TileID> tileCover(const LatLngBounds& bounds_, int32_t z, int32_t actualZ) { + if (bounds_.isEmpty() || + bounds_.south() > util::LATITUDE_MAX || + bounds_.north() < -util::LATITUDE_MAX) { + return {}; + } + + LatLngBounds bounds = LatLngBounds::hull( + { std::max(bounds_.south(), -util::LATITUDE_MAX), bounds_.west() }, + { std::min(bounds_.north(), util::LATITUDE_MAX), bounds_.east() }); + + const TransformState state; + return tileCover( + state.latLngToCoordinate(bounds.northwest()), + state.latLngToCoordinate(bounds.northeast()), + state.latLngToCoordinate(bounds.southeast()), + state.latLngToCoordinate(bounds.southwest()), + state.latLngToCoordinate(bounds.center()), + z, actualZ); +} + +std::vector<TileID> tileCover(const TransformState& state, int32_t z, int32_t actualZ) { + const double w = state.getWidth(); + const double h = state.getHeight(); + return tileCover( + state.pointToCoordinate({ 0, 0 }), + state.pointToCoordinate({ w, 0 }), + state.pointToCoordinate({ w, h }), + state.pointToCoordinate({ 0, h }), + state.pointToCoordinate({ w/2, h/2 }), + z, actualZ); } } // namespace mbgl |