Map::nudgeTransitions no longer depends on client information

Clients no longer need to provide data (eg. if gesturing or in a custom
animation) to Map::nudgeTransitions().

Upon MapContext::renderSync(), a new atomic bool 'needsRepaint' in MapData
allows thread-safe communication between Map and MapContext.

4 files changed, 29 insertions, 21 deletions

diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index 4990d24fc2..fadd4c48d9 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -48,33 +48,31 @@ void Map::renderStill(StillImageCallback callback) {
                     FrameData{ view.getFramebufferSize() }, callback);
 }
 
-bool Map::renderSync() {
+void Map::renderSync() {
     if (renderState == RenderState::never) {
         view.notifyMapChange(MapChangeWillStartRenderingMap);
     }
 
     view.notifyMapChange(MapChangeWillStartRenderingFrame);
 
-    MapContext::RenderResult result = context->invokeSync<MapContext::RenderResult>(
-        &MapContext::renderSync, transform->getState(), FrameData{ view.getFramebufferSize() });
+    const bool fullyLoaded = context->invokeSync<bool>(
+            &MapContext::renderSync, transform->getState(), FrameData { view.getFramebufferSize() });
 
-    view.notifyMapChange(result.fullyLoaded ?
+    view.notifyMapChange(fullyLoaded ?
         MapChangeDidFinishRenderingFrameFullyRendered :
         MapChangeDidFinishRenderingFrame);
 
-    if (!result.fullyLoaded) {
+    if (!fullyLoaded) {
         renderState = RenderState::partial;
     } else if (renderState != RenderState::fully) {
         renderState = RenderState::fully;
         view.notifyMapChange(MapChangeDidFinishRenderingMapFullyRendered);
     }
-
-    return result.needsRerender;
 }
 
-void Map::nudgeTransitions(bool forceRerender) {
+void Map::nudgeTransitions() {
     UpdateType update_ = transform->updateTransitions(Clock::now());
-    if (forceRerender) {
+    if (data->getNeedsRepaint()) {
         update_ |= static_cast<UpdateType>(Update::Repaint);
     }
     update(Update(update_));
diff --git a/src/mbgl/map/map_context.cpp b/src/mbgl/map/map_context.cpp
index 4f8052f299..33e4e6d181 100644
--- a/src/mbgl/map/map_context.cpp
+++ b/src/mbgl/map/map_context.cpp
@@ -256,6 +256,9 @@ void MapContext::update() {
 
     if (!style) {
         updated = static_cast<UpdateType>(Update::Nothing);
+    }
+
+    if (updated == static_cast<UpdateType>(Update::Nothing)) {
         return;
     }
 
@@ -315,12 +318,12 @@ void MapContext::renderStill(const TransformState& state, const FrameData& frame
     asyncUpdate->send();
 }
 
-MapContext::RenderResult MapContext::renderSync(const TransformState& state, const FrameData& frame) {
+bool MapContext::renderSync(const TransformState& state, const FrameData& frame) {
     assert(util::ThreadContext::currentlyOn(util::ThreadType::Map));
 
     // Style was not loaded yet.
     if (!style) {
-        return { false, false };
+        return false;
     }
 
     transformState = state;
@@ -345,10 +348,11 @@ MapContext::RenderResult MapContext::renderSync(const TransformState& state, con
 
     viewInvalidated = false;
 
-    return RenderResult {
-        isLoaded(),
-        style->hasTransitions() || painter->needsAnimation()
-    };
+    if (style->hasTransitions() || painter->needsAnimation()) {
+        data.setNeedsRepaint(true);
+    }
+
+    return isLoaded();
 }
 
 bool MapContext::isLoaded() const {
diff --git a/src/mbgl/map/map_context.hpp b/src/mbgl/map/map_context.hpp
index dd211d4a17..215f5d377a 100644
--- a/src/mbgl/map/map_context.hpp
+++ b/src/mbgl/map/map_context.hpp
@@ -38,16 +38,13 @@ public:
     MapContext(View&, FileSource&, MapData&);
     ~MapContext();
 
-    struct RenderResult {
-        bool fullyLoaded;
-        bool needsRerender;
-    };
-
     void pause();
 
     void triggerUpdate(const TransformState&, Update = Update::Nothing);
     void renderStill(const TransformState&, const FrameData&, Map::StillImageCallback callback);
-    RenderResult renderSync(const TransformState&, const FrameData&);
+
+    // Triggers a synchronous render. Returns true if style has been fully loaded.
+    bool renderSync(const TransformState&, const FrameData&);
 
     void setStyleURL(const std::string&);
     void setStyleJSON(const std::string& json, const std::string& base);
diff --git a/src/mbgl/map/map_data.hpp b/src/mbgl/map/map_data.hpp
index aadc8dcd64..9eac6162eb 100644
--- a/src/mbgl/map/map_data.hpp
+++ b/src/mbgl/map/map_data.hpp
@@ -101,6 +101,14 @@ public:
         defaultTransitionDelay = delay;
     }
 
+    inline bool getNeedsRepaint() const {
+        return needsRepaint;
+    }
+
+    inline void setNeedsRepaint(const bool needsRepaint_) {
+        needsRepaint = needsRepaint_;
+    }
+
     util::exclusive<AnnotationManager> getAnnotationManager() {
         return util::exclusive<AnnotationManager>(
             &annotationManager,
@@ -124,6 +132,7 @@ private:
     std::atomic<Duration> defaultFadeDuration;
     std::atomic<Duration> defaultTransitionDuration;
     std::atomic<Duration> defaultTransitionDelay;
+    std::atomic<bool> needsRepaint;
 
 // TODO: make private
 public: