From 427773d31a5b1ad156b923aaf44ea9d2015f5be9 Mon Sep 17 00:00:00 2001
From: Bruno de Oliveira Abinader <bruno@mapbox.com>
Date: Thu, 30 Jun 2016 13:55:14 +0300
Subject: [core] Micro-optimizations in geometry code

---
 src/mbgl/style/source_impl.cpp | 11 +++++++++--
 src/mbgl/style/style.cpp       |  5 ++++-
 src/mbgl/util/grid_index.cpp   | 17 ++++++++++-------
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/mbgl/style/source_impl.cpp b/src/mbgl/style/source_impl.cpp
index 4223f2b50d..95363ca699 100644
--- a/src/mbgl/style/source_impl.cpp
+++ b/src/mbgl/style/source_impl.cpp
@@ -207,6 +207,11 @@ static Point<int16_t> coordinateToTilePoint(const UnwrappedTileID& tileID, const
 }
 
 std::unordered_map<std::string, std::vector<Feature>> Source::Impl::queryRenderedFeatures(const QueryParameters& parameters) const {
+    std::unordered_map<std::string, std::vector<Feature>> result;
+    if (renderTiles.empty()) {
+        return result;
+    }
+
     LineString<double> queryGeometry;
 
     for (const auto& p : parameters.geometry) {
@@ -214,9 +219,11 @@ std::unordered_map<std::string, std::vector<Feature>> Source::Impl::queryRendere
             parameters.transformState, 0, { p.x, parameters.transformState.getHeight() - p.y }).p);
     }
 
-    mapbox::geometry::box<double> box = mapbox::geometry::envelope(queryGeometry);
+    if (queryGeometry.empty()) {
+        return result;
+    }
 
-    std::unordered_map<std::string, std::vector<Feature>> result;
+    mapbox::geometry::box<double> box = mapbox::geometry::envelope(queryGeometry);
 
     for (const auto& tilePtr : renderTiles) {
         const RenderTile& tile = tilePtr.second;
diff --git a/src/mbgl/style/style.cpp b/src/mbgl/style/style.cpp
index 9073894cc2..aae0e38d51 100644
--- a/src/mbgl/style/style.cpp
+++ b/src/mbgl/style/style.cpp
@@ -337,6 +337,7 @@ RenderData Style::getRenderData(MapDebugOptions debugOptions) const {
 }
 
 std::vector<Feature> Style::queryRenderedFeatures(const QueryParameters& parameters) const {
+    std::vector<Feature> result;
     std::unordered_map<std::string, std::vector<Feature>> resultsByLayer;
 
     for (const auto& source : sources) {
@@ -344,7 +345,9 @@ std::vector<Feature> Style::queryRenderedFeatures(const QueryParameters& paramet
         std::move(sourceResults.begin(), sourceResults.end(), std::inserter(resultsByLayer, resultsByLayer.begin()));
     }
 
-    std::vector<Feature> result;
+    if (resultsByLayer.empty()) {
+        return result;
+    }
 
     // Combine all results based on the style layer order.
     for (const auto& layer : layers) {
diff --git a/src/mbgl/util/grid_index.cpp b/src/mbgl/util/grid_index.cpp
index cf1fcd68c9..b3afd3fdc8 100644
--- a/src/mbgl/util/grid_index.cpp
+++ b/src/mbgl/util/grid_index.cpp
@@ -1,5 +1,6 @@
 #include <mbgl/util/grid_index.hpp>
 #include <mbgl/geometry/feature_index.hpp>
+#include <mbgl/math/minmax.hpp>
 
 #include <unordered_set>
 
@@ -28,9 +29,10 @@ void GridIndex<T>::insert(T&& t, const BBox& bbox) {
     auto cx2 = convertToCellCoord(bbox.max.x);
     auto cy2 = convertToCellCoord(bbox.max.y);
 
-    for (int32_t x = cx1; x <= cx2; x++) {
-        for (int32_t y = cy1; y <= cy2; y++) {
-            auto cellIndex = d * y + x;
+    int32_t x, y, cellIndex;
+    for (x = cx1; x <= cx2; ++x) {
+        for (y = cy1; y <= cy2; ++y) {
+            cellIndex = d * y + x;
             cells[cellIndex].push_back(uid);
         }
     }
@@ -48,9 +50,10 @@ std::vector<T> GridIndex<T>::query(const BBox& queryBBox) const {
     auto cx2 = convertToCellCoord(queryBBox.max.x);
     auto cy2 = convertToCellCoord(queryBBox.max.y);
 
-    for (int32_t x = cx1; x <= cx2; x++) {
-        for (int32_t y = cy1; y <= cy2; y++) {
-            auto cellIndex = d * y + x;
+    int32_t x, y, cellIndex;
+    for (x = cx1; x <= cx2; ++x) {
+        for (y = cy1; y <= cy2; ++y) {
+            cellIndex = d * y + x;
             for (auto uid : cells[cellIndex]) {
                 if (seenUids.count(uid) == 0) {
                     seenUids.insert(uid);
@@ -75,7 +78,7 @@ std::vector<T> GridIndex<T>::query(const BBox& queryBBox) const {
 
 template <class T>
 int32_t GridIndex<T>::convertToCellCoord(int32_t x) const {
-    return std::max(0.0, std::min(d - 1.0, std::floor(x * scale) + padding));
+    return util::max(0.0, util::min(d - 1.0, std::floor(x * scale) + padding));
 }
 
 template class GridIndex<IndexedSubfeature>;
-- 
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