From d735d89835fb3076e09594fce2a141fe1495e33f Mon Sep 17 00:00:00 2001
From: Chris Loer <chris.loer@gmail.com>
Date: Thu, 6 Sep 2018 14:58:37 -0700
Subject: [core] Port "collision group" plumbing to gl-native. [node] Hook up
 map-wide "crossSourceCollisions" option, defaulting to true. [test] Pass
 "crossSourceCollisions" test option through test harness; enable
 cross-source-collisions tests on native.

---
 include/mbgl/map/map.hpp                   |  3 ++-
 platform/node/CHANGELOG.md                 |  1 +
 platform/node/src/node_map.cpp             | 18 ++++++++++++--
 platform/node/src/node_map.hpp             |  1 +
 platform/node/test/ignores.json            |  2 --
 platform/node/test/suite_implementation.js |  8 +++---
 src/mbgl/geometry/feature_index.hpp        |  5 +++-
 src/mbgl/map/map.cpp                       | 17 +++++++++----
 src/mbgl/renderer/renderer_impl.cpp        |  4 +--
 src/mbgl/renderer/update_parameters.hpp    |  2 ++
 src/mbgl/text/collision_index.cpp          | 34 ++++++++++++++++++--------
 src/mbgl/text/collision_index.hpp          |  8 +++---
 src/mbgl/text/placement.cpp                | 39 ++++++++++++++++++++++++------
 src/mbgl/text/placement.hpp                | 24 ++++++++++++++++--
 src/mbgl/tile/geometry_tile.hpp            |  4 +--
 src/mbgl/util/grid_index.cpp               | 24 ++++++++++++------
 src/mbgl/util/grid_index.hpp               |  5 ++--
 17 files changed, 149 insertions(+), 50 deletions(-)

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 3aee932070..ca6c62d280 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -37,7 +37,8 @@ public:
                  Scheduler&,
                  MapMode mapMode = MapMode::Continuous,
                  ConstrainMode constrainMode = ConstrainMode::HeightOnly,
-                 ViewportMode viewportMode = ViewportMode::Default);
+                 ViewportMode viewportMode = ViewportMode::Default,
+                 bool crossSourceCollisions = true);
     ~Map();
 
     // Register a callback that will get called (on the render thread) when all resources have
diff --git a/platform/node/CHANGELOG.md b/platform/node/CHANGELOG.md
index 5b44d5be1f..fc8d2afe7b 100644
--- a/platform/node/CHANGELOG.md
+++ b/platform/node/CHANGELOG.md
@@ -6,6 +6,7 @@
 - Remove unnecessary memory use when collision debug mode is not enabled ([#12294](https://github.com/mapbox/mapbox-gl-native/issues/12294))
 - Added support for rendering `symbol-placement: line-center` ([#12337](https://github.com/mapbox/mapbox-gl-native/pull/12337))
 - Add support for feature expressions in `line-pattern`, `fill-pattern`, and `fill-extrusion-pattern` properties. [#12284](https://github.com/mapbox/mapbox-gl-native/pull/12284)
+- Add `crossSourceCollisions` map option, with default of `true`. When set to `false`, cross-source collision detection is disabled. ([#12820] (https://github.com/mapbox/mapbox-gl-native/issues/12820))
 
 # 3.5.8 - October 19, 2017
 - Fixes an issue that causes memory leaks when not deleting the frontend object
diff --git a/platform/node/src/node_map.cpp b/platform/node/src/node_map.cpp
index 7dbccfcf41..e32c576e14 100644
--- a/platform/node/src/node_map.cpp
+++ b/platform/node/src/node_map.cpp
@@ -621,7 +621,10 @@ void NodeMap::cancel() {
 
     frontend = std::make_unique<mbgl::HeadlessFrontend>(mbgl::Size{ 256, 256 }, pixelRatio, *this, threadpool);
     map = std::make_unique<mbgl::Map>(*frontend, mapObserver, frontend->getSize(), pixelRatio,
-                                      *this, threadpool, mode);
+                                      *this, threadpool, mode,
+                                      mbgl::ConstrainMode::HeightOnly,
+                                      mbgl::ViewportMode::Default,
+                                      crossSourceCollisions);
 
     // FIXME: Reload the style after recreating the map. We need to find
     // a better way of canceling an ongoing rendering on the core level
@@ -1212,6 +1215,14 @@ NodeMap::NodeMap(v8::Local<v8::Object> options)
                 return mbgl::MapMode::Static;
             }
       }())
+    , crossSourceCollisions([&] {
+        Nan::HandleScope scope;
+        return Nan::Has(options, Nan::New("crossSourceCollisions").ToLocalChecked()).FromJust()
+            ? Nan::Get(options, Nan::New("crossSourceCollisions").ToLocalChecked())
+                .ToLocalChecked()
+                ->BooleanValue()
+            : true;
+    }())
     , mapObserver(NodeMapObserver())
     , frontend(std::make_unique<mbgl::HeadlessFrontend>(mbgl::Size { 256, 256 }, pixelRatio, *this, threadpool))
     , map(std::make_unique<mbgl::Map>(*frontend,
@@ -1220,7 +1231,10 @@ NodeMap::NodeMap(v8::Local<v8::Object> options)
                                       pixelRatio,
                                       *this,
                                       threadpool,
-                                      mode)),
+                                      mode,
+                                      mbgl::ConstrainMode::HeightOnly,
+                                      mbgl::ViewportMode::Default,
+                                      crossSourceCollisions)),
       async(new uv_async_t) {
 
     async->data = this;
diff --git a/platform/node/src/node_map.hpp b/platform/node/src/node_map.hpp
index 52fc1ef659..b83a238681 100644
--- a/platform/node/src/node_map.hpp
+++ b/platform/node/src/node_map.hpp
@@ -82,6 +82,7 @@ public:
 
     const float pixelRatio;
     mbgl::MapMode mode;
+    bool crossSourceCollisions;
     NodeThreadPool threadpool;
     NodeMapObserver mapObserver;
     std::unique_ptr<mbgl::HeadlessFrontend> frontend;
diff --git a/platform/node/test/ignores.json b/platform/node/test/ignores.json
index d2ec3644d9..67f0ff9a72 100644
--- a/platform/node/test/ignores.json
+++ b/platform/node/test/ignores.json
@@ -95,7 +95,6 @@
   "render-tests/geojson/inline-linestring-fill": "current behavior is arbitrary",
   "render-tests/geojson/inline-polygon-symbol": "behavior needs reconciliation with gl-js",
   "render-tests/icon-rotate/with-offset": "https://github.com/mapbox/mapbox-gl-native/issues/11872",
-  "render-tests/icon-no-cross-source-collision/default": "skip - gl-js only",
   "render-tests/mixed-zoom/z10-z11": "https://github.com/mapbox/mapbox-gl-native/issues/10397",
   "render-tests/raster-masking/overlapping-zoom": "https://github.com/mapbox/mapbox-gl-native/issues/10195",
   "render-tests/real-world/bangkok": "https://github.com/mapbox/mapbox-gl-native/issues/10412",
@@ -122,7 +121,6 @@
   "render-tests/text-field/formatted-arabic": "skip - https://github.com/mapbox/mapbox-gl-native/pull/12624",
   "render-tests/text-field/formatted-line": "skip - https://github.com/mapbox/mapbox-gl-native/pull/12624",
   "render-tests/text-field/formatted": "skip - https://github.com/mapbox/mapbox-gl-native/pull/12624",
-  "render-tests/text-no-cross-source-collision/default": "skip - gl-js only",
   "render-tests/text-pitch-alignment/auto-text-rotation-alignment-map": "https://github.com/mapbox/mapbox-gl-native/issues/9732",
   "render-tests/text-pitch-alignment/map-text-rotation-alignment-map": "https://github.com/mapbox/mapbox-gl-native/issues/9732",
   "render-tests/text-pitch-alignment/viewport-text-rotation-alignment-map": "https://github.com/mapbox/mapbox-gl-native/issues/9732",
diff --git a/platform/node/test/suite_implementation.js b/platform/node/test/suite_implementation.js
index 704cab8940..f868af8ece 100644
--- a/platform/node/test/suite_implementation.js
+++ b/platform/node/test/suite_implementation.js
@@ -16,7 +16,7 @@ export default function (style, options, callback) {
     let map;
 
     if (options.recycleMap) {
-        const key = options.pixelRatio + '/' + tileMode;
+        const key = options.pixelRatio + '/' + tileMode + '/' + options.crossSourceCollisions;
         if (maps.has(key)) {
             map = maps.get(key);
             map.request = mapRequest;
@@ -24,7 +24,8 @@ export default function (style, options, callback) {
             maps.set(key, new mbgl.Map({
                 ratio: options.pixelRatio,
                 request: mapRequest,
-                mode: options.mapMode
+                mode: options.mapMode,
+                crossSourceCollisions: typeof options.crossSourceCollisions === "undefined" ? true : options.crossSourceCollisions
             }));
             map = maps.get(key);
         }
@@ -32,7 +33,8 @@ export default function (style, options, callback) {
         map = new mbgl.Map({
             ratio: options.pixelRatio,
             request: mapRequest,
-            mode: options.mapMode
+            mode: options.mapMode,
+            crossSourceCollisions: typeof options.crossSourceCollisions === "undefined" ? true : options.crossSourceCollisions
         });
     }
 
diff --git a/src/mbgl/geometry/feature_index.hpp b/src/mbgl/geometry/feature_index.hpp
index 739c1f282f..cd041a7fdb 100644
--- a/src/mbgl/geometry/feature_index.hpp
+++ b/src/mbgl/geometry/feature_index.hpp
@@ -28,15 +28,17 @@ public:
         , bucketLeaderID(std::move(bucketName_))
         , sortIndex(sortIndex_)
         , bucketInstanceId(0)
+        , collisionGroupId(0)
     {}
     
     
-    IndexedSubfeature(const IndexedSubfeature& other, uint32_t bucketInstanceId_)
+    IndexedSubfeature(const IndexedSubfeature& other, uint32_t bucketInstanceId_, uint16_t collisionGroupId_)
         : index(other.index)
         , sourceLayerName(other.sourceLayerName)
         , bucketLeaderID(other.bucketLeaderID)
         , sortIndex(other.sortIndex)
         , bucketInstanceId(bucketInstanceId_)
+        , collisionGroupId(collisionGroupId_)
     {}
     size_t index;
     std::string sourceLayerName;
@@ -45,6 +47,7 @@ public:
 
     // Only used for symbol features
     uint32_t bucketInstanceId;
+    uint16_t collisionGroupId;
 };
 
 class FeatureIndex {
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index ddac5c5c8f..9d886cb74c 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -44,7 +44,8 @@ public:
          Scheduler&,
          MapMode,
          ConstrainMode,
-         ViewportMode);
+         ViewportMode,
+         bool);
 
     ~Impl();
 
@@ -73,6 +74,7 @@ public:
 
     const MapMode mode;
     const float pixelRatio;
+    const bool crossSourceCollisions;
 
     MapDebugOptions debugOptions { MapDebugOptions::NoDebug };
 
@@ -96,7 +98,8 @@ Map::Map(RendererFrontend& rendererFrontend,
          Scheduler& scheduler,
          MapMode mapMode,
          ConstrainMode constrainMode,
-         ViewportMode viewportMode)
+         ViewportMode viewportMode,
+         bool crossSourceCollisions)
     : impl(std::make_unique<Impl>(*this,
                                   rendererFrontend,
                                   mapObserver,
@@ -105,7 +108,8 @@ Map::Map(RendererFrontend& rendererFrontend,
                                   scheduler,
                                   mapMode,
                                   constrainMode,
-                                  viewportMode)) {
+                                  viewportMode,
+                                  crossSourceCollisions)) {
     impl->transform.resize(size);
 }
 
@@ -117,7 +121,8 @@ Map::Impl::Impl(Map& map_,
                 Scheduler& scheduler_,
                 MapMode mode_,
                 ConstrainMode constrainMode_,
-                ViewportMode viewportMode_)
+                ViewportMode viewportMode_,
+                bool crossSourceCollisions_)
     : map(map_),
       observer(mapObserver),
       rendererFrontend(frontend),
@@ -128,6 +133,7 @@ Map::Impl::Impl(Map& map_,
                 viewportMode_),
       mode(mode_),
       pixelRatio(pixelRatio_),
+      crossSourceCollisions(crossSourceCollisions_),
       style(std::make_unique<Style>(scheduler, fileSource, pixelRatio)),
       annotationManager(*style) {
 
@@ -783,7 +789,8 @@ void Map::Impl::onUpdate() {
         style->impl->getLayerImpls(),
         annotationManager,
         prefetchZoomDelta,
-        bool(stillImageRequest)
+        bool(stillImageRequest),
+        crossSourceCollisions
     };
 
     rendererFrontend.update(std::make_shared<UpdateParameters>(std::move(params)));
diff --git a/src/mbgl/renderer/renderer_impl.cpp b/src/mbgl/renderer/renderer_impl.cpp
index 92d04063ca..6f7814190d 100644
--- a/src/mbgl/renderer/renderer_impl.cpp
+++ b/src/mbgl/renderer/renderer_impl.cpp
@@ -61,7 +61,7 @@ Renderer::Impl::Impl(RendererBackend& backend_,
     , sourceImpls(makeMutable<std::vector<Immutable<style::Source::Impl>>>())
     , layerImpls(makeMutable<std::vector<Immutable<style::Layer::Impl>>>())
     , renderLight(makeMutable<Light::Impl>())
-    , placement(std::make_unique<Placement>(TransformState{}, MapMode::Static)) {
+    , placement(std::make_unique<Placement>(TransformState{}, MapMode::Static, true)) {
     glyphManager->setObserver(this);
 }
 
@@ -398,7 +398,7 @@ void Renderer::Impl::render(const UpdateParameters& updateParameters) {
     if (!placement->stillRecent(parameters.timePoint)) {
         placementChanged = true;
 
-        auto newPlacement = std::make_unique<Placement>(parameters.state, parameters.mapMode);
+        auto newPlacement = std::make_unique<Placement>(parameters.state, parameters.mapMode, updateParameters.crossSourceCollisions);
         std::set<std::string> usedSymbolLayers;
         for (auto it = order.rbegin(); it != order.rend(); ++it) {
             if (it->layer.is<RenderSymbolLayer>()) {
diff --git a/src/mbgl/renderer/update_parameters.hpp b/src/mbgl/renderer/update_parameters.hpp
index b54abc050d..a668c64f48 100644
--- a/src/mbgl/renderer/update_parameters.hpp
+++ b/src/mbgl/renderer/update_parameters.hpp
@@ -38,6 +38,8 @@ public:
     
     // For still image requests, render requested
     const bool stillImageRequest;
+    
+    const bool crossSourceCollisions;
 };
 
 } // namespace mbgl
diff --git a/src/mbgl/text/collision_index.cpp b/src/mbgl/text/collision_index.cpp
index dae789a196..90acb2b441 100644
--- a/src/mbgl/text/collision_index.cpp
+++ b/src/mbgl/text/collision_index.cpp
@@ -89,7 +89,8 @@ std::pair<bool,bool> CollisionIndex::placeFeature(CollisionFeature& feature,
                                       const bool allowOverlap,
                                       const bool pitchWithMap,
                                       const bool collisionDebug,
-                                      const optional<CollisionTileBoundaries>& avoidEdges) {
+                                      const optional<CollisionTileBoundaries>& avoidEdges,
+                                      const optional<std::function<bool(const IndexedSubfeature&)>> collisionGroupPredicate) {
     if (!feature.alongLine) {
         CollisionBox& box = feature.boxes.front();
         const auto projectedPoint = projectAndGetPerspectiveRatio(posMatrix, box.anchor);
@@ -102,13 +103,13 @@ std::pair<bool,bool> CollisionIndex::placeFeature(CollisionFeature& feature,
 
         if ((avoidEdges && !isInsideTile(box, *avoidEdges)) ||
             !isInsideGrid(box) ||
-            (!allowOverlap && collisionGrid.hitTest({{ box.px1, box.py1 }, { box.px2, box.py2 }}))) {
+            (!allowOverlap && collisionGrid.hitTest({{ box.px1, box.py1 }, { box.px2, box.py2 }}, collisionGroupPredicate))) {
             return { false, false };
         }
 
         return {true, isOffscreen(box)};
     } else {
-        return placeLineFeature(feature, posMatrix, labelPlaneMatrix, textPixelRatio, symbol, scale, fontSize, allowOverlap, pitchWithMap, collisionDebug, avoidEdges);
+        return placeLineFeature(feature, posMatrix, labelPlaneMatrix, textPixelRatio, symbol, scale, fontSize, allowOverlap, pitchWithMap, collisionDebug, avoidEdges, collisionGroupPredicate);
     }
 }
 
@@ -122,7 +123,8 @@ std::pair<bool,bool> CollisionIndex::placeLineFeature(CollisionFeature& feature,
                                       const bool allowOverlap,
                                       const bool pitchWithMap,
                                       const bool collisionDebug,
-                                      const optional<CollisionTileBoundaries>& avoidEdges) {
+                                      const optional<CollisionTileBoundaries>& avoidEdges,
+                                      const optional<std::function<bool(const IndexedSubfeature&)>> collisionGroupPredicate) {
 
     const auto tileUnitAnchorPoint = symbol.anchorPoint;
     const auto projectedAnchor = projectAnchor(posMatrix, tileUnitAnchorPoint);
@@ -222,7 +224,7 @@ std::pair<bool,bool> CollisionIndex::placeLineFeature(CollisionFeature& feature,
         inGrid |= isInsideGrid(circle);
 
         if ((avoidEdges && !isInsideTile(circle, *avoidEdges)) ||
-            (!allowOverlap && collisionGrid.hitTest({{circle.px, circle.py}, circle.radius}))) {
+            (!allowOverlap && collisionGrid.hitTest({{circle.px, circle.py}, circle.radius}, collisionGroupPredicate))) {
             if (!collisionDebug) {
                 return {false, false};
             } else {
@@ -237,7 +239,7 @@ std::pair<bool,bool> CollisionIndex::placeLineFeature(CollisionFeature& feature,
 }
 
 
-void CollisionIndex::insertFeature(CollisionFeature& feature, bool ignorePlacement, uint32_t bucketInstanceId) {
+void CollisionIndex::insertFeature(CollisionFeature& feature, bool ignorePlacement, uint32_t bucketInstanceId, uint16_t collisionGroupId) {
     if (feature.alongLine) {
         for (auto& circle : feature.boxes) {
             if (!circle.used) {
@@ -245,18 +247,30 @@ void CollisionIndex::insertFeature(CollisionFeature& feature, bool ignorePlaceme
             }
 
             if (ignorePlacement) {
-                ignoredGrid.insert(IndexedSubfeature(feature.indexedFeature, bucketInstanceId), {{ circle.px, circle.py }, circle.radius});
+                ignoredGrid.insert(
+                    IndexedSubfeature(feature.indexedFeature, bucketInstanceId, collisionGroupId),
+                    {{ circle.px, circle.py }, circle.radius}
+                );
             } else {
-                collisionGrid.insert(IndexedSubfeature(feature.indexedFeature, bucketInstanceId), {{ circle.px, circle.py }, circle.radius});
+                collisionGrid.insert(
+                    IndexedSubfeature(feature.indexedFeature, bucketInstanceId, collisionGroupId),
+                    {{ circle.px, circle.py }, circle.radius}
+                );
             }
         }
     } else {
         assert(feature.boxes.size() == 1);
         auto& box = feature.boxes[0];
         if (ignorePlacement) {
-            ignoredGrid.insert(IndexedSubfeature(feature.indexedFeature, bucketInstanceId), {{ box.px1, box.py1 }, { box.px2, box.py2 }});
+            ignoredGrid.insert(
+                IndexedSubfeature(feature.indexedFeature, bucketInstanceId, collisionGroupId),
+                {{ box.px1, box.py1 }, { box.px2, box.py2 }}
+            );
         } else {
-            collisionGrid.insert(IndexedSubfeature(feature.indexedFeature, bucketInstanceId), {{ box.px1, box.py1 }, { box.px2, box.py2 }});
+            collisionGrid.insert(
+                IndexedSubfeature(feature.indexedFeature, bucketInstanceId, collisionGroupId),
+                {{ box.px1, box.py1 }, { box.px2, box.py2 }}
+            );
         }
     }
 }
diff --git a/src/mbgl/text/collision_index.hpp b/src/mbgl/text/collision_index.hpp
index 78782fe61c..dac0aa0bf7 100644
--- a/src/mbgl/text/collision_index.hpp
+++ b/src/mbgl/text/collision_index.hpp
@@ -32,9 +32,10 @@ public:
                                       const bool allowOverlap,
                                       const bool pitchWithMap,
                                       const bool collisionDebug,
-                                      const optional<CollisionTileBoundaries>& avoidEdges);
+                                      const optional<CollisionTileBoundaries>& avoidEdges,
+                                      const optional<std::function<bool(const IndexedSubfeature&)>> collisionGroupPredicate);
 
-    void insertFeature(CollisionFeature& feature, bool ignorePlacement, uint32_t bucketInstanceId);
+    void insertFeature(CollisionFeature& feature, bool ignorePlacement, uint32_t bucketInstanceId, uint16_t collisionGroupId);
 
     std::unordered_map<uint32_t, std::vector<IndexedSubfeature>> queryRenderedSymbols(const ScreenLineString&) const;
     
@@ -55,7 +56,8 @@ private:
                                   const bool allowOverlap,
                                   const bool pitchWithMap,
                                   const bool collisionDebug,
-                                  const optional<CollisionTileBoundaries>& avoidEdges);
+                                  const optional<CollisionTileBoundaries>& avoidEdges,
+                                  const optional<std::function<bool(const IndexedSubfeature&)>> collisionGroupPredicate);
     
     float approximateTileDistance(const TileDistance& tileDistance, const float lastSegmentAngle, const float pixelsToTileUnits, const float cameraToAnchorDistance, const bool pitchWithMap);
     
diff --git a/src/mbgl/text/placement.cpp b/src/mbgl/text/placement.cpp
index 48c58a962e..5c6cdcde6c 100644
--- a/src/mbgl/text/placement.cpp
+++ b/src/mbgl/text/placement.cpp
@@ -33,11 +33,33 @@ JointOpacityState::JointOpacityState(const JointOpacityState& prevOpacityState,
 bool JointOpacityState::isHidden() const {
     return icon.isHidden() && text.isHidden();
 }
+    
+const CollisionGroups::CollisionGroup& CollisionGroups::get(const std::string& sourceID) {
+    // The predicate/groupID mechanism allows for arbitrary grouping,
+    // but the current interface defines one source == one group when
+    // crossSourceCollisions == true.
+    if (!crossSourceCollisions) {
+        if (collisionGroups.find(sourceID) == collisionGroups.end()) {
+            uint16_t nextGroupID = ++maxGroupID;
+            collisionGroups.emplace(sourceID, CollisionGroup(
+                nextGroupID,
+                optional<Predicate>([nextGroupID](const IndexedSubfeature& feature) -> bool {
+                    return feature.collisionGroupId == nextGroupID;
+                })
+            ));
+        }
+        return collisionGroups[sourceID];
+    } else {
+        static CollisionGroup nullGroup{0, nullopt};
+        return nullGroup;
+    }
+}
 
-Placement::Placement(const TransformState& state_, MapMode mapMode_)
+Placement::Placement(const TransformState& state_, MapMode mapMode_, const bool crossSourceCollisions)
     : collisionIndex(state_)
     , state(state_)
     , mapMode(mapMode_)
+    , collisionGroups(crossSourceCollisions)
 {}
 
 void Placement::placeLayer(RenderSymbolLayer& symbolLayer, const mat4& projMatrix, bool showCollisionBoxes) {
@@ -92,7 +114,9 @@ void Placement::placeLayer(RenderSymbolLayer& symbolLayer, const mat4& projMatri
                                   std::forward_as_tuple(symbolBucket.bucketInstanceId),
                                   std::forward_as_tuple(symbolBucket.bucketInstanceId, geometryTile.getFeatureIndex(), geometryTile.id));
         
-        placeLayerBucket(symbolBucket, posMatrix, textLabelPlaneMatrix, iconLabelPlaneMatrix, scale, textPixelRatio, showCollisionBoxes, seenCrossTileIDs, renderTile.tile.holdForFade());
+        const auto collisionGroup = collisionGroups.get(geometryTile.sourceID);
+        
+        placeLayerBucket(symbolBucket, posMatrix, textLabelPlaneMatrix, iconLabelPlaneMatrix, scale, textPixelRatio, showCollisionBoxes, seenCrossTileIDs, renderTile.tile.holdForFade(), collisionGroup);
     }
 }
 
@@ -105,7 +129,8 @@ void Placement::placeLayerBucket(
         const float textPixelRatio,
         const bool showCollisionBoxes,
         std::unordered_set<uint32_t>& seenCrossTileIDs,
-        const bool holdingForFade) {
+        const bool holdingForFade,
+        const CollisionGroups::CollisionGroup& collisionGroup) {
 
     auto partiallyEvaluatedTextSize = bucket.textSizeBinder->evaluateForZoom(state.getZoom());
     auto partiallyEvaluatedIconSize = bucket.iconSizeBinder->evaluateForZoom(state.getZoom());
@@ -159,7 +184,7 @@ void Placement::placeLayerBucket(
                         placedSymbol, scale, fontSize,
                         bucket.layout.get<style::TextAllowOverlap>(),
                         bucket.layout.get<style::TextPitchAlignment>() == style::AlignmentType::Map,
-                        showCollisionBoxes, avoidEdges);
+                        showCollisionBoxes, avoidEdges, collisionGroup.second);
                 placeText = placed.first;
                 offscreen &= placed.second;
             }
@@ -173,7 +198,7 @@ void Placement::placeLayerBucket(
                         placedSymbol, scale, fontSize,
                         bucket.layout.get<style::IconAllowOverlap>(),
                         bucket.layout.get<style::IconPitchAlignment>() == style::AlignmentType::Map,
-                        showCollisionBoxes, avoidEdges);
+                        showCollisionBoxes, avoidEdges, collisionGroup.second);
                 placeIcon = placed.first;
                 offscreen &= placed.second;
             }
@@ -191,11 +216,11 @@ void Placement::placeLayerBucket(
             }
 
             if (placeText) {
-                collisionIndex.insertFeature(symbolInstance.textCollisionFeature, bucket.layout.get<style::TextIgnorePlacement>(), bucket.bucketInstanceId);
+                collisionIndex.insertFeature(symbolInstance.textCollisionFeature, bucket.layout.get<style::TextIgnorePlacement>(), bucket.bucketInstanceId, collisionGroup.first);
             }
 
             if (placeIcon) {
-                collisionIndex.insertFeature(symbolInstance.iconCollisionFeature, bucket.layout.get<style::IconIgnorePlacement>(), bucket.bucketInstanceId);
+                collisionIndex.insertFeature(symbolInstance.iconCollisionFeature, bucket.layout.get<style::IconIgnorePlacement>(), bucket.bucketInstanceId, collisionGroup.first);
             }
 
             assert(symbolInstance.crossTileID != 0);
diff --git a/src/mbgl/text/placement.hpp b/src/mbgl/text/placement.hpp
index 24de4c054a..8527d6df57 100644
--- a/src/mbgl/text/placement.hpp
+++ b/src/mbgl/text/placement.hpp
@@ -59,9 +59,27 @@ struct RetainedQueryData {
         , tileID(std::move(tileID_)) {}
 };
     
+class CollisionGroups {
+public:
+    using Predicate = std::function<bool(const IndexedSubfeature&)>;
+    using CollisionGroup = std::pair<uint16_t, optional<Predicate>>;
+    
+    CollisionGroups(const bool crossSourceCollisions_)
+        : maxGroupID(0)
+        , crossSourceCollisions(crossSourceCollisions_)
+    {}
+    
+    const CollisionGroup& get(const std::string& sourceID);
+    
+private:
+    std::map<std::string, CollisionGroup> collisionGroups;
+    uint16_t maxGroupID;
+    bool crossSourceCollisions;
+};
+    
 class Placement {
 public:
-    Placement(const TransformState&, MapMode mapMode);
+    Placement(const TransformState&, MapMode mapMode, const bool crossSourceCollisions);
     void placeLayer(RenderSymbolLayer&, const mat4&, bool showCollisionBoxes);
     void commit(const Placement& prevPlacement, TimePoint);
     void updateLayerOpacities(RenderSymbolLayer&);
@@ -86,7 +104,8 @@ private:
             const float pixelRatio,
             const bool showCollisionBoxes,
             std::unordered_set<uint32_t>& seenCrossTileIDs,
-            const bool holdingForFade);
+            const bool holdingForFade,
+            const CollisionGroups::CollisionGroup& collisionGroup);
 
     void updateBucketOpacities(SymbolBucket&, std::set<uint32_t>&);
 
@@ -103,6 +122,7 @@ private:
     bool stale = false;
     
     std::unordered_map<uint32_t, RetainedQueryData> retainedQueryData;
+    CollisionGroups collisionGroups;
 };
 
 } // namespace mbgl
diff --git a/src/mbgl/tile/geometry_tile.hpp b/src/mbgl/tile/geometry_tile.hpp
index 3d0ca03a82..c5c7cb6623 100644
--- a/src/mbgl/tile/geometry_tile.hpp
+++ b/src/mbgl/tile/geometry_tile.hpp
@@ -91,6 +91,8 @@ public:
     const optional<ImagePosition> getPattern(const std::string& pattern);
     const std::shared_ptr<FeatureIndex> getFeatureIndex() const { return latestFeatureIndex; }
     
+    const std::string sourceID;
+    
 protected:
     const GeometryTileData* getData() {
         return latestFeatureIndex ? latestFeatureIndex->getData() : nullptr;
@@ -99,8 +101,6 @@ protected:
 private:
     void markObsolete();
 
-    const std::string sourceID;
-
     // Used to signal the worker that it should abandon parsing this tile as soon as possible.
     std::atomic<bool> obsolete { false };
 
diff --git a/src/mbgl/util/grid_index.cpp b/src/mbgl/util/grid_index.cpp
index afd469501d..f6b59b1bac 100644
--- a/src/mbgl/util/grid_index.cpp
+++ b/src/mbgl/util/grid_index.cpp
@@ -82,21 +82,29 @@ std::vector<std::pair<T, typename GridIndex<T>::BBox>> GridIndex<T>::queryWithBo
 }
 
 template <class T>
-bool GridIndex<T>::hitTest(const BBox& queryBBox) const {
+bool GridIndex<T>::hitTest(const BBox& queryBBox, optional<std::function<bool(const T&)>> predicate) const {
     bool hit = false;
-    query(queryBBox, [&](const T&, const BBox&) -> bool {
-        hit = true;
-        return true;
+    query(queryBBox, [&](const T& t, const BBox&) -> bool {
+        if (!predicate || (*predicate)(t)) {
+            hit = true;
+            return true;
+        } else {
+            return false;
+        }
     });
     return hit;
 }
 
 template <class T>
-bool GridIndex<T>::hitTest(const BCircle& queryBCircle) const {
+bool GridIndex<T>::hitTest(const BCircle& queryBCircle, optional<std::function<bool(const T&)>> predicate) const {
     bool hit = false;
-    query(queryBCircle, [&](const T&, const BBox&) -> bool {
-        hit = true;
-        return true;
+    query(queryBCircle, [&](const T& t, const BBox&) -> bool {
+        if (!predicate || (*predicate)(t)) {
+            hit = true;
+            return true;
+        } else {
+            return false;
+        }
     });
     return hit;
 }
diff --git a/src/mbgl/util/grid_index.hpp b/src/mbgl/util/grid_index.hpp
index 6ef2966bee..4c2d7dccc8 100644
--- a/src/mbgl/util/grid_index.hpp
+++ b/src/mbgl/util/grid_index.hpp
@@ -2,6 +2,7 @@
 
 #include <mapbox/geometry/point.hpp>
 #include <mapbox/geometry/box.hpp>
+#include <mbgl/util/optional.hpp>
 
 #include <cstdint>
 #include <cstddef>
@@ -67,8 +68,8 @@ public:
     std::vector<T> query(const BBox&) const;
     std::vector<std::pair<T,BBox>> queryWithBoxes(const BBox&) const;
     
-    bool hitTest(const BBox&) const;
-    bool hitTest(const BCircle&) const;
+    bool hitTest(const BBox&, optional<std::function<bool(const T&)>> predicate = nullopt) const;
+    bool hitTest(const BCircle&, optional<std::function<bool(const T&)>> predicate = nullopt) const;
     
     bool empty() const;
 
-- 
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