From 88093bd708dccb1082bb624a6c27e5aa7688b77a Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Wed, 3 May 2017 09:50:06 -0700
Subject: [PATCH] [core] Calculate hasPendingTransitions functionally rather
 than statefully

---
 src/mbgl/renderer/render_background_layer.cpp     |  4 +++-
 src/mbgl/renderer/render_background_layer.hpp     |  3 ++-
 src/mbgl/renderer/render_circle_layer.cpp         |  4 +++-
 src/mbgl/renderer/render_circle_layer.hpp         |  3 ++-
 src/mbgl/renderer/render_custom_layer.cpp         |  5 ++++-
 src/mbgl/renderer/render_custom_layer.hpp         |  3 ++-
 src/mbgl/renderer/render_fill_extrusion_layer.cpp |  4 +++-
 src/mbgl/renderer/render_fill_extrusion_layer.hpp |  3 ++-
 src/mbgl/renderer/render_fill_layer.cpp           |  7 ++++---
 src/mbgl/renderer/render_fill_layer.hpp           |  3 ++-
 src/mbgl/renderer/render_layer.hpp                |  4 +++-
 src/mbgl/renderer/render_line_layer.cpp           |  5 ++++-
 src/mbgl/renderer/render_line_layer.hpp           |  3 ++-
 src/mbgl/renderer/render_raster_layer.cpp         |  4 +++-
 src/mbgl/renderer/render_raster_layer.hpp         |  3 ++-
 src/mbgl/renderer/render_symbol_layer.cpp         |  7 ++++---
 src/mbgl/renderer/render_symbol_layer.hpp         |  3 ++-
 src/mbgl/style/style.cpp                          | 15 ++++++++++++---
 src/mbgl/style/style.hpp                          |  2 +-
 19 files changed, 60 insertions(+), 25 deletions(-)

diff --git a/src/mbgl/renderer/render_background_layer.cpp b/src/mbgl/renderer/render_background_layer.cpp
index a6b4a5e36..485d4b16c 100644
--- a/src/mbgl/renderer/render_background_layer.cpp
+++ b/src/mbgl/renderer/render_background_layer.cpp
@@ -23,12 +23,14 @@ void RenderBackgroundLayer::cascade(const CascadeParameters &parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderBackgroundLayer::evaluate(const PropertyEvaluationParameters &parameters) {
+void RenderBackgroundLayer::evaluate(const PropertyEvaluationParameters &parameters) {
     evaluated = unevaluated.evaluate(parameters);
 
     passes = evaluated.get<style::BackgroundOpacity>() > 0 ? RenderPass::Translucent
                                                            : RenderPass::None;
+}
 
+bool RenderBackgroundLayer::hasTransition() const {
     return unevaluated.hasTransition();
 }
 
diff --git a/src/mbgl/renderer/render_background_layer.hpp b/src/mbgl/renderer/render_background_layer.hpp
index 137980389..b1f709953 100644
--- a/src/mbgl/renderer/render_background_layer.hpp
+++ b/src/mbgl/renderer/render_background_layer.hpp
@@ -15,7 +15,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     std::unique_ptr<Bucket> createBucket(const BucketParameters&, const std::vector<const RenderLayer*>&) const override;
 
diff --git a/src/mbgl/renderer/render_circle_layer.cpp b/src/mbgl/renderer/render_circle_layer.cpp
index 56832d53c..f59c174dd 100644
--- a/src/mbgl/renderer/render_circle_layer.cpp
+++ b/src/mbgl/renderer/render_circle_layer.cpp
@@ -24,7 +24,7 @@ void RenderCircleLayer::cascade(const CascadeParameters& parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderCircleLayer::evaluate(const PropertyEvaluationParameters& parameters) {
+void RenderCircleLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     evaluated = unevaluated.evaluate(parameters);
 
     passes = ((evaluated.get<style::CircleRadius>().constantOr(1) > 0 ||
@@ -34,7 +34,9 @@ bool RenderCircleLayer::evaluate(const PropertyEvaluationParameters& parameters)
               && (evaluated.get<style::CircleOpacity>().constantOr(1) > 0 ||
                   evaluated.get<style::CircleStrokeOpacity>().constantOr(1) > 0))
              ? RenderPass::Translucent : RenderPass::None;
+}
 
+bool RenderCircleLayer::hasTransition() const {
     return unevaluated.hasTransition();
 }
 
diff --git a/src/mbgl/renderer/render_circle_layer.hpp b/src/mbgl/renderer/render_circle_layer.hpp
index 8a2f73ec8..3b82b5c98 100644
--- a/src/mbgl/renderer/render_circle_layer.hpp
+++ b/src/mbgl/renderer/render_circle_layer.hpp
@@ -15,7 +15,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     bool queryIntersectsFeature(
             const GeometryCoordinates&,
diff --git a/src/mbgl/renderer/render_custom_layer.cpp b/src/mbgl/renderer/render_custom_layer.cpp
index d500d11f4..66dd57b3d 100644
--- a/src/mbgl/renderer/render_custom_layer.cpp
+++ b/src/mbgl/renderer/render_custom_layer.cpp
@@ -13,8 +13,11 @@ std::unique_ptr<RenderLayer> RenderCustomLayer::clone() const {
     return std::make_unique<RenderCustomLayer>(*this);
 }
 
-bool RenderCustomLayer::evaluate(const PropertyEvaluationParameters&) {
+void RenderCustomLayer::evaluate(const PropertyEvaluationParameters&) {
     passes = RenderPass::Translucent;
+}
+
+bool RenderCustomLayer::hasTransition() const {
     return false;
 }
 
diff --git a/src/mbgl/renderer/render_custom_layer.hpp b/src/mbgl/renderer/render_custom_layer.hpp
index cb728fecb..c3af6c77b 100644
--- a/src/mbgl/renderer/render_custom_layer.hpp
+++ b/src/mbgl/renderer/render_custom_layer.hpp
@@ -14,7 +14,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) final {}
-    bool evaluate(const PropertyEvaluationParameters&) final;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     std::unique_ptr<Bucket> createBucket(const BucketParameters&, const std::vector<const RenderLayer*>&) const final;
 
diff --git a/src/mbgl/renderer/render_fill_extrusion_layer.cpp b/src/mbgl/renderer/render_fill_extrusion_layer.cpp
index 70ee74b56..f6ba164d8 100644
--- a/src/mbgl/renderer/render_fill_extrusion_layer.cpp
+++ b/src/mbgl/renderer/render_fill_extrusion_layer.cpp
@@ -24,12 +24,14 @@ void RenderFillExtrusionLayer::cascade(const CascadeParameters& parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderFillExtrusionLayer::evaluate(const PropertyEvaluationParameters& parameters) {
+void RenderFillExtrusionLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     evaluated = unevaluated.evaluate(parameters);
 
     passes = (evaluated.get<style::FillExtrusionOpacity>() > 0) ? RenderPass::Translucent
                                                          : RenderPass::None;
+}
 
+bool RenderFillExtrusionLayer::hasTransition() const {
     return unevaluated.hasTransition();
 }
 
diff --git a/src/mbgl/renderer/render_fill_extrusion_layer.hpp b/src/mbgl/renderer/render_fill_extrusion_layer.hpp
index b4fd1411f..bd66d8e3b 100644
--- a/src/mbgl/renderer/render_fill_extrusion_layer.hpp
+++ b/src/mbgl/renderer/render_fill_extrusion_layer.hpp
@@ -15,7 +15,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     bool queryIntersectsFeature(
         const GeometryCoordinates&,
diff --git a/src/mbgl/renderer/render_fill_layer.cpp b/src/mbgl/renderer/render_fill_layer.cpp
index 53c1ff303..1af139cde 100644
--- a/src/mbgl/renderer/render_fill_layer.cpp
+++ b/src/mbgl/renderer/render_fill_layer.cpp
@@ -24,7 +24,7 @@ void RenderFillLayer::cascade(const CascadeParameters& parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderFillLayer::evaluate(const PropertyEvaluationParameters& parameters) {
+void RenderFillLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     evaluated = unevaluated.evaluate(parameters);
 
     if (unevaluated.get<style::FillOutlineColor>().isUndefined()) {
@@ -44,10 +44,11 @@ bool RenderFillLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     } else {
         passes |= RenderPass::Opaque;
     }
-
-    return unevaluated.hasTransition();
 }
 
+bool RenderFillLayer::hasTransition() const {
+    return unevaluated.hasTransition();
+}
 
 bool RenderFillLayer::queryIntersectsFeature(
         const GeometryCoordinates& queryGeometry,
diff --git a/src/mbgl/renderer/render_fill_layer.hpp b/src/mbgl/renderer/render_fill_layer.hpp
index 3a8de3622..8080cf289 100644
--- a/src/mbgl/renderer/render_fill_layer.hpp
+++ b/src/mbgl/renderer/render_fill_layer.hpp
@@ -15,7 +15,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     bool queryIntersectsFeature(
             const GeometryCoordinates&,
diff --git a/src/mbgl/renderer/render_layer.hpp b/src/mbgl/renderer/render_layer.hpp
index 003059005..eea2ec1f6 100644
--- a/src/mbgl/renderer/render_layer.hpp
+++ b/src/mbgl/renderer/render_layer.hpp
@@ -33,8 +33,10 @@ public:
     virtual void cascade(const CascadeParameters&) = 0;
 
     // Fully evaluate cascaded paint properties based on a zoom level.
+    virtual void evaluate(const PropertyEvaluationParameters&) = 0;
+
     // Returns true if any paint properties have active transitions.
-    virtual bool evaluate(const PropertyEvaluationParameters&) = 0;
+    virtual bool hasTransition() const = 0;
 
     // Check whether this layer is of the given subtype.
     template <class T>
diff --git a/src/mbgl/renderer/render_line_layer.cpp b/src/mbgl/renderer/render_line_layer.cpp
index e5060af79..06c256451 100644
--- a/src/mbgl/renderer/render_line_layer.cpp
+++ b/src/mbgl/renderer/render_line_layer.cpp
@@ -24,7 +24,7 @@ void RenderLineLayer::cascade(const CascadeParameters& parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderLineLayer::evaluate(const PropertyEvaluationParameters& parameters) {
+void RenderLineLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     // for scaling dasharrays
     auto dashArrayParams = parameters;
     dashArrayParams.z = std::floor(dashArrayParams.z);
@@ -36,9 +36,12 @@ bool RenderLineLayer::evaluate(const PropertyEvaluationParameters& parameters) {
               && evaluated.get<style::LineColor>().constantOr(Color::black()).a > 0
               && evaluated.get<style::LineWidth>() > 0)
              ? RenderPass::Translucent : RenderPass::None;
+}
 
+bool RenderLineLayer::hasTransition() const {
     return unevaluated.hasTransition();
 }
+
 optional<GeometryCollection> offsetLine(const GeometryCollection& rings, const double offset) {
     if (offset == 0) return {};
 
diff --git a/src/mbgl/renderer/render_line_layer.hpp b/src/mbgl/renderer/render_line_layer.hpp
index 15052deb3..6d6fecc22 100644
--- a/src/mbgl/renderer/render_line_layer.hpp
+++ b/src/mbgl/renderer/render_line_layer.hpp
@@ -15,7 +15,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     bool queryIntersectsFeature(
             const GeometryCoordinates&,
diff --git a/src/mbgl/renderer/render_raster_layer.cpp b/src/mbgl/renderer/render_raster_layer.cpp
index 0cfccc81b..5e664e6f5 100644
--- a/src/mbgl/renderer/render_raster_layer.cpp
+++ b/src/mbgl/renderer/render_raster_layer.cpp
@@ -22,11 +22,13 @@ void RenderRasterLayer::cascade(const CascadeParameters& parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderRasterLayer::evaluate(const PropertyEvaluationParameters& parameters) {
+void RenderRasterLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     evaluated = unevaluated.evaluate(parameters);
 
     passes = evaluated.get<style::RasterOpacity>() > 0 ? RenderPass::Translucent : RenderPass::None;
+}
 
+bool RenderRasterLayer::hasTransition() const {
     return unevaluated.hasTransition();
 }
 
diff --git a/src/mbgl/renderer/render_raster_layer.hpp b/src/mbgl/renderer/render_raster_layer.hpp
index c6e38fa14..3ffeb8feb 100644
--- a/src/mbgl/renderer/render_raster_layer.hpp
+++ b/src/mbgl/renderer/render_raster_layer.hpp
@@ -15,7 +15,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     std::unique_ptr<Bucket> createBucket(const BucketParameters&, const std::vector<const RenderLayer*>&) const override;
 
diff --git a/src/mbgl/renderer/render_symbol_layer.cpp b/src/mbgl/renderer/render_symbol_layer.cpp
index 0c3601aed..30d769e03 100644
--- a/src/mbgl/renderer/render_symbol_layer.cpp
+++ b/src/mbgl/renderer/render_symbol_layer.cpp
@@ -38,7 +38,7 @@ void RenderSymbolLayer::cascade(const CascadeParameters& parameters) {
     unevaluated = impl->cascading.cascade(parameters, std::move(unevaluated));
 }
 
-bool RenderSymbolLayer::evaluate(const PropertyEvaluationParameters& parameters) {
+void RenderSymbolLayer::evaluate(const PropertyEvaluationParameters& parameters) {
     evaluated = unevaluated.evaluate(parameters);
 
     auto hasIconOpacity = evaluated.get<style::IconColor>().constantOr(Color::black()).a > 0 ||
@@ -49,10 +49,11 @@ bool RenderSymbolLayer::evaluate(const PropertyEvaluationParameters& parameters)
     passes = ((evaluated.get<style::IconOpacity>().constantOr(1) > 0 && hasIconOpacity && iconSize > 0)
               || (evaluated.get<style::TextOpacity>().constantOr(1) > 0 && hasTextOpacity && textSize > 0))
              ? RenderPass::Translucent : RenderPass::None;
-
-    return unevaluated.hasTransition();
 }
 
+bool RenderSymbolLayer::hasTransition() const {
+    return unevaluated.hasTransition();
+}
 
 style::IconPaintProperties::Evaluated RenderSymbolLayer::iconPaintProperties() const {
     return style::IconPaintProperties::Evaluated {
diff --git a/src/mbgl/renderer/render_symbol_layer.hpp b/src/mbgl/renderer/render_symbol_layer.hpp
index b9c2cc324..80ffd95a0 100644
--- a/src/mbgl/renderer/render_symbol_layer.hpp
+++ b/src/mbgl/renderer/render_symbol_layer.hpp
@@ -67,7 +67,8 @@ public:
     std::unique_ptr<RenderLayer> clone() const override;
 
     void cascade(const CascadeParameters&) override;
-    bool evaluate(const PropertyEvaluationParameters&) override;
+    void evaluate(const PropertyEvaluationParameters&) override;
+    bool hasTransition() const override;
 
     style::IconPaintProperties::Evaluated iconPaintProperties() const;
     style::TextPaintProperties::Evaluated textPaintProperties() const;
diff --git a/src/mbgl/style/style.cpp b/src/mbgl/style/style.cpp
index 23536e0e3..a3c7ce1ad 100644
--- a/src/mbgl/style/style.cpp
+++ b/src/mbgl/style/style.cpp
@@ -387,9 +387,8 @@ void Style::recalculate(float z, const TimePoint& timePoint, MapMode mode) {
         mode == MapMode::Continuous ? util::DEFAULT_FADE_DURATION : Duration::zero()
     };
 
-    hasPendingTransitions = transitioningLight.hasTransition();
     for (const auto& layer : renderLayers) {
-        hasPendingTransitions |= layer->evaluate(parameters);
+        layer->evaluate(parameters);
 
         if (layer->needsRendering(zoomHistory.lastZoom)) {
             if (RenderSource* renderSource = getRenderSource(layer->baseImpl.source)) {
@@ -443,7 +442,17 @@ RenderSource* Style::getRenderSource(const std::string& id) const {
 }
 
 bool Style::hasTransitions() const {
-    return hasPendingTransitions;
+    if (transitioningLight.hasTransition()) {
+        return true;
+    }
+
+    for (const auto& layer : renderLayers) {
+        if (layer->hasTransition()) {
+            return true;
+        }
+    }
+
+    return false;
 }
 
 bool Style::isLoaded() const {
diff --git a/src/mbgl/style/style.hpp b/src/mbgl/style/style.hpp
index fe588c3ce..c7528483e 100644
--- a/src/mbgl/style/style.hpp
+++ b/src/mbgl/style/style.hpp
@@ -180,9 +180,9 @@ private:
 
     UpdateBatch updateBatch;
     ZoomHistory zoomHistory;
-    bool hasPendingTransitions = false;
 
     void removeRenderLayer(const std::string& layerID);
+
 public:
     bool loaded = false;
 };