[core] Simplify RenderLayer interface.

src/mbgl/renderer/layers/render_heatmap_layer.cpp

@@ -32,6 +32,7 @@ RenderHeatmapLayer::~RenderHeatmapLayer() = default;
 
 void RenderHeatmapLayer::transition(const TransitionParameters& parameters) {
     unevaluated = impl(baseImpl).paint.transitioned(parameters, std::move(unevaluated));
+    updateColorRamp();
 }
 
 void RenderHeatmapLayer::evaluate(const PropertyEvaluationParameters& parameters) {
@@ -189,10 +190,6 @@ void RenderHeatmapLayer::render(PaintParameters& parameters, RenderSource*) {
     }
 }
 
-void RenderHeatmapLayer::update() {
-    updateColorRamp();
-}
-
 void RenderHeatmapLayer::updateColorRamp() {
     auto colorValue = unevaluated.get<HeatmapColor>().getValue();
     if (colorValue.isUndefined()) {

src/mbgl/renderer/layers/render_heatmap_layer.hpp

@@ -20,7 +20,6 @@ private:
     bool hasTransition() const override;
     bool hasCrossfade() const override;
     void render(PaintParameters&, RenderSource*) override;
-    void update() final;
 
     bool queryIntersectsFeature(
             const GeometryCoordinates&,

src/mbgl/renderer/layers/render_line_layer.cpp

@@ -32,6 +32,7 @@ RenderLineLayer::~RenderLineLayer() = default;
 
 void RenderLineLayer::transition(const TransitionParameters& parameters) {
     unevaluated = impl(baseImpl).paint.transitioned(parameters, std::move(unevaluated));
+    updateColorRamp();
 }
 
 void RenderLineLayer::evaluate(const PropertyEvaluationParameters& parameters) {
@@ -279,8 +280,4 @@ float RenderLineLayer::getLineWidth(const GeometryTileFeature& feature, const fl
     }
 }
 
-void RenderLineLayer::update() {
-    updateColorRamp();
-}
-
 } // namespace mbgl

src/mbgl/renderer/layers/render_line_layer.hpp

@@ -21,7 +21,6 @@ private:
     bool hasTransition() const override;
     bool hasCrossfade() const override;
     void render(PaintParameters&, RenderSource*) override;
-    void update() override;
 
     bool queryIntersectsFeature(
             const GeometryCoordinates&,

src/mbgl/renderer/render_layer.cpp

@@ -15,8 +15,9 @@ RenderLayer::RenderLayer(Immutable<style::LayerProperties> properties)
       baseImpl(evaluatedProperties->baseImpl) {
 }
 
-void RenderLayer::setImpl(Immutable<style::Layer::Impl> impl) {
-    baseImpl = std::move(impl);
+void RenderLayer::transition(const TransitionParameters& parameters, Immutable<style::Layer::Impl> newImpl) {
+    baseImpl = std::move(newImpl);
+    transition(parameters);
 }
 
 const std::string& RenderLayer::getID() const {
@@ -43,10 +44,6 @@ const RenderLayerSymbolInterface* RenderLayer::getSymbolInterface() const {
     return nullptr;
 }
 
-void RenderLayer::update() {
-    // no-op
-}
-
 optional<Color> RenderLayer::getSolidBackground() const {
     return nullopt;
 }

src/mbgl/renderer/render_layer.hpp

@@ -35,6 +35,9 @@ public:
     // Begin transitions for any properties that have changed since the last frame.
     virtual void transition(const TransitionParameters&) = 0;
 
+    // Overloaded version for transitions to a new layer impl.
+    void transition(const TransitionParameters&, Immutable<style::Layer::Impl> newImpl);
+
     // Fully evaluate possibly-transitioning paint properties based on a zoom level.
     // Updates the contained `evaluatedProperties` member.
     virtual void evaluate(const PropertyEvaluationParameters&) = 0;
@@ -75,15 +78,9 @@ public:
     Immutable<style::LayerProperties> evaluatedProperties;
     // Private implementation
     Immutable<style::Layer::Impl> baseImpl;
-    void setImpl(Immutable<style::Layer::Impl>);
 
     virtual void markContextDestroyed();
 
-    // TODO: Figure out how to remove this or whether layers other than
-    // RenderHeatmapLayer and RenderLineLayer need paint property updates,
-    // similar to color ramp. Temporarily moved to the base.
-    virtual void update();
-
     // TODO: Only for background layers.
     virtual optional<Color> getSolidBackground() const;
 

src/mbgl/renderer/renderer_impl.cpp

@@ -175,12 +175,14 @@ void Renderer::Impl::render(const UpdateParameters& updateParameters) {
 
     // Create render layers for newly added layers.
     for (const auto& entry : layerDiff.added) {
-        renderLayers.emplace(entry.first, LayerManager::get()->createRenderLayer(entry.second));
+        auto renderLayer = LayerManager::get()->createRenderLayer(entry.second);
+        renderLayer->transition(transitionParameters);
+        renderLayers.emplace(entry.first, std::move(renderLayer));
     }
 
     // Update render layers for changed layers.
     for (const auto& entry : layerDiff.changed) {
-        renderLayers.at(entry.first)->setImpl(entry.second.after);
+        renderLayers.at(entry.first)->transition(transitionParameters, entry.second.after);
     }
 
     if (!layerDiff.removed.empty() || !layerDiff.added.empty() || !layerDiff.changed.empty()) {
@@ -191,12 +193,6 @@ void Renderer::Impl::render(const UpdateParameters& updateParameters) {
     for (const auto& entry : renderLayers) {
         RenderLayer& layer = *entry.second;
         const bool layerAddedOrChanged = layerDiff.added.count(entry.first) || layerDiff.changed.count(entry.first);
-
-        if (layerAddedOrChanged) {
-            layer.transition(transitionParameters);
-            layer.update();
-        }
-
         if (layerAddedOrChanged || zoomChanged || layer.hasTransition() || layer.hasCrossfade()) {
             layer.evaluate(evaluationParameters);
         }