[core] don't use floating point versions of pow/log

GLIBC 2.27 added new versioned symbols of powf and logf, while the double versions of pow and log remained stable.
Prefer the double version to avoid introducing a dependency on a newer version of GLIBC than strictly necessary.
See https://lists.gnu.org/archive/html/info-gnu/2018-02/msg00000.html

3 files changed, 4 insertions, 3 deletions

diff --git a/src/mbgl/util/interpolate.cpp b/src/mbgl/util/interpolate.cpp
index 066fa9c462..6b5736f15f 100644
--- a/src/mbgl/util/interpolate.cpp
+++ b/src/mbgl/util/interpolate.cpp
@@ -13,7 +13,8 @@ float interpolationFactor(float base, Range<float> range, float z) {
     } else if (base == 1.0f) {
         return zoomProgress / zoomDiff;
     } else {
-        return (std::pow(base, zoomProgress) - 1) / (std::pow(base, zoomDiff) - 1);
+        return (std::pow(static_cast<double>(base), zoomProgress) - 1) /
+               (std::pow(static_cast<double>(base), zoomDiff) - 1);
     }
 }
 
diff --git a/src/mbgl/util/tile_coordinate.hpp b/src/mbgl/util/tile_coordinate.hpp
index bcd1c8444f..b6bdc5f590 100644
--- a/src/mbgl/util/tile_coordinate.hpp
+++ b/src/mbgl/util/tile_coordinate.hpp
@@ -20,7 +20,7 @@ public:
 
     static TileCoordinate fromLatLng(double zoom, const LatLng& latLng) {
         const double scale = std::pow(2.0, zoom);
-        return { Projection::project(latLng, scale) / double(util::tileSize), zoom };
+        return { Projection::project(latLng, scale) / util::tileSize, zoom };
     }
 
     static TileCoordinate fromScreenCoordinate(const TransformState& state, double zoom, const ScreenCoordinate& screenCoordinate) {
diff --git a/src/mbgl/util/tile_cover.cpp b/src/mbgl/util/tile_cover.cpp
index 488e6b88ce..3f39e53d40 100644
--- a/src/mbgl/util/tile_cover.cpp
+++ b/src/mbgl/util/tile_cover.cpp
@@ -130,7 +130,7 @@ std::vector<UnwrappedTileID> tileCover(const Point<double>& tl,
 } // namespace
 
 int32_t coveringZoomLevel(double zoom, style::SourceType type, uint16_t size) {
-    zoom += std::log(util::tileSize / size) / std::log(2);
+    zoom += ::log2(util::tileSize / size);
     if (type == style::SourceType::Raster || type == style::SourceType::Video) {
         return ::round(zoom);
     } else {