[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

2 files changed, 3 insertions, 3 deletions

diff --git a/src/mbgl/renderer/layers/render_symbol_layer.cpp b/src/mbgl/renderer/layers/render_symbol_layer.cpp
index e48c0e2f92..3a3545122e 100644
--- a/src/mbgl/renderer/layers/render_symbol_layer.cpp
+++ b/src/mbgl/renderer/layers/render_symbol_layer.cpp
@@ -234,7 +234,7 @@ void RenderSymbolLayer::render(PaintParameters& parameters, RenderSource*) {
             static const CollisionBoxProgram::PaintPropertyBinders paintAttributeData(properties, 0);
 
             auto pixelRatio = tile.id.pixelsToTileUnits(1, parameters.state.getZoom());
-            auto scale = std::pow(2.0f, float(parameters.state.getZoom() - tile.tile.id.overscaledZ));
+            const float scale = std::pow(2, parameters.state.getZoom() - tile.tile.id.overscaledZ);
             std::array<float,2> extrudeScale =
                 {{
                     parameters.pixelsToGLUnits[0] / (pixelRatio * scale),
@@ -267,7 +267,7 @@ void RenderSymbolLayer::render(PaintParameters& parameters, RenderSource*) {
             static const CollisionBoxProgram::PaintPropertyBinders paintAttributeData(properties, 0);
 
             auto pixelRatio = tile.id.pixelsToTileUnits(1, parameters.state.getZoom());
-            auto scale = std::pow(2.0f, float(parameters.state.getZoom() - tile.tile.id.overscaledZ));
+            const float scale = std::pow(2, parameters.state.getZoom() - tile.tile.id.overscaledZ);
             std::array<float,2> extrudeScale =
                 {{
                     parameters.pixelsToGLUnits[0] / (pixelRatio * scale),
diff --git a/src/mbgl/renderer/sources/render_image_source.cpp b/src/mbgl/renderer/sources/render_image_source.cpp
index dce5e40185..2ce046a7a0 100644
--- a/src/mbgl/renderer/sources/render_image_source.cpp
+++ b/src/mbgl/renderer/sources/render_image_source.cpp
@@ -139,7 +139,7 @@ void RenderImageSource::update(Immutable<style::Source::Impl> baseImpl_,
     auto dx = nePoint.x - swPoint.x;
     auto dy = nePoint.y - swPoint.y;
     auto dMax = std::max(dx, dy);
-    double zoom = std::max(0.0, std::floor(-util::log2(dMax)));
+    double zoom = std::max(0.0, std::floor(-::log2(dMax)));
 
     // Only enable if the long side of the image is > 2 pixels. Resulting in a
     // display of at least 2 x 1 px image