[core] Avoid extra copy of TransformState in Painter::render

In MapContext thread, TransformState gets updated from main thread to
MapContext and Painter can safely reference MapContext's TransformState
instead of copying it upon each Painter::render call.

8 files changed, 20 insertions, 21 deletions

diff --git a/src/mbgl/map/map_context.cpp b/src/mbgl/map/map_context.cpp
index aa8aecd09b..6fbd35ad78 100644
--- a/src/mbgl/map/map_context.cpp
+++ b/src/mbgl/map/map_context.cpp
@@ -242,8 +242,8 @@ bool MapContext::renderSync(const TransformState& state, const FrameData& frame)
     // Cleanup OpenGL objects that we abandoned since the last render call.
     glObjectStore.performCleanup();
 
-    if (!painter) painter = std::make_unique<Painter>(data);
-    painter->render(*style, transformState, frame);
+    if (!painter) painter = std::make_unique<Painter>(data, transformState);
+    painter->render(*style, frame);
 
     if (data.mode == MapMode::Still) {
         callback(nullptr, view.readStillImage());
diff --git a/src/mbgl/map/map_context.hpp b/src/mbgl/map/map_context.hpp
index 433d5ecea5..f4df3aae25 100644
--- a/src/mbgl/map/map_context.hpp
+++ b/src/mbgl/map/map_context.hpp
@@ -21,13 +21,8 @@ class View;
 class MapData;
 class TexturePool;
 class Painter;
-class Sprite;
-class Worker;
-class StillImage;
 class SpriteImage;
 class FileRequest;
-struct LatLng;
-struct LatLngBounds;
 
 struct FrameData {
     std::array<uint16_t, 2> framebufferSize;
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index 3c451d00eb..91fe87791e 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -159,7 +159,7 @@ void Transform::setLatLngZoom(const LatLng& latLng, double zoom, const Duration&
 
 #pragma mark - Zoom
 
-void Transform::scaleBy(const double ds, const PrecisionPoint& center, const Duration& duration) {
+void Transform::scaleBy(double ds, const PrecisionPoint& center, const Duration& duration) {
     if (std::isnan(ds) || !center) {
         return;
     }
@@ -175,7 +175,7 @@ void Transform::scaleBy(const double ds, const PrecisionPoint& center, const Dur
     _setScale(new_scale, center, duration);
 }
 
-void Transform::setScale(const double scale, const PrecisionPoint& center, const Duration& duration) {
+void Transform::setScale(double scale, const PrecisionPoint& center, const Duration& duration) {
     if (std::isnan(scale) || !center) {
         return;
     }
@@ -183,7 +183,7 @@ void Transform::setScale(const double scale, const PrecisionPoint& center, const
     _setScale(scale, center, duration);
 }
 
-void Transform::setZoom(const double zoom, const Duration& duration) {
+void Transform::setZoom(double zoom, const Duration& duration) {
     if (std::isnan(zoom)) {
         return;
     }
@@ -225,7 +225,7 @@ void Transform::_setScale(double new_scale, const PrecisionPoint& center, const
     _setScaleXY(new_scale, xn, yn, duration);
 }
 
-void Transform::_setScaleXY(const double new_scale, const double xn, const double yn,
+void Transform::_setScaleXY(double new_scale, double xn, double yn,
                             const Duration& duration) {
     CameraOptions options;
     options.duration = duration;
@@ -332,7 +332,7 @@ void Transform::rotateBy(const PrecisionPoint& first, const PrecisionPoint& seco
     _setAngle(ang, duration);
 }
 
-void Transform::setAngle(const double new_angle, const Duration& duration) {
+void Transform::setAngle(double new_angle, const Duration& duration) {
     if (std::isnan(new_angle)) {
         return;
     }
@@ -340,7 +340,7 @@ void Transform::setAngle(const double new_angle, const Duration& duration) {
     _setAngle(new_angle, duration);
 }
 
-void Transform::setAngle(const double new_angle, const PrecisionPoint& center) {
+void Transform::setAngle(double new_angle, const PrecisionPoint& center) {
     if (std::isnan(new_angle) || !center) {
         return;
     }
diff --git a/src/mbgl/map/transform.hpp b/src/mbgl/map/transform.hpp
index ec057dedda..0fc900dac7 100644
--- a/src/mbgl/map/transform.hpp
+++ b/src/mbgl/map/transform.hpp
@@ -60,7 +60,7 @@ public:
     bool isGestureInProgress() const { return state.isGestureInProgress(); }
 
     // Transform state
-    const TransformState getState() const { return state; }
+    TransformState getState() const { return state; }
     bool isRotating() const { return state.isRotating(); }
     bool isScaling() const { return state.isScaling(); }
     bool isPanning() const { return state.isPanning(); }
diff --git a/src/mbgl/map/transform_state.cpp b/src/mbgl/map/transform_state.cpp
index cb094577a3..f58bfde8df 100644
--- a/src/mbgl/map/transform_state.cpp
+++ b/src/mbgl/map/transform_state.cpp
@@ -7,6 +7,10 @@
 
 using namespace mbgl;
 
+TransformState::TransformState()
+{
+}
+
 #pragma mark - Matrix
 
 void TransformState::matrixFor(mat4& matrix, const TileID& id, const int8_t z) const {
diff --git a/src/mbgl/map/transform_state.hpp b/src/mbgl/map/transform_state.hpp
index b99595564f..0373798f00 100644
--- a/src/mbgl/map/transform_state.hpp
+++ b/src/mbgl/map/transform_state.hpp
@@ -21,6 +21,8 @@ class TransformState {
     friend class Transform;
 
 public:
+    TransformState();
+
     // Matrix
     void matrixFor(mat4& matrix, const TileID& id, const int8_t z) const;
     void getProjMatrix(mat4& matrix) const;
diff --git a/src/mbgl/renderer/painter.cpp b/src/mbgl/renderer/painter.cpp
index 284bed3705..a3902fece0 100644
--- a/src/mbgl/renderer/painter.cpp
+++ b/src/mbgl/renderer/painter.cpp
@@ -43,7 +43,8 @@
 
 using namespace mbgl;
 
-Painter::Painter(MapData& data_) : data(data_) {
+Painter::Painter(MapData& data_, TransformState& state_)
+    : data(data_), state(state_) {
     setup();
 }
 
@@ -127,8 +128,7 @@ void Painter::prepareTile(const Tile& tile) {
     config.stencilFunc = { GL_EQUAL, ref, mask };
 }
 
-void Painter::render(const Style& style, TransformState state_, const FrameData& frame_) {
-    state = state_;
+void Painter::render(const Style& style, const FrameData& frame_) {
     frame = frame_;
 
     glyphAtlas = style.glyphAtlas.get();
diff --git a/src/mbgl/renderer/painter.hpp b/src/mbgl/renderer/painter.hpp
index 8f63388461..5de1031d23 100644
--- a/src/mbgl/renderer/painter.hpp
+++ b/src/mbgl/renderer/painter.hpp
@@ -82,7 +82,7 @@ struct RenderItem {
 
 class Painter : private util::noncopyable {
 public:
-    Painter(MapData& data);
+    Painter(MapData&, TransformState&);
     ~Painter();
 
     // Renders the backdrop of the OpenGL view. This also paints in areas where we don't have any
@@ -93,7 +93,6 @@ public:
     void changeMatrix();
 
     void render(const Style& style,
-                TransformState state,
                 const FrameData& frame);
 
     // Renders debug information for a tile.
@@ -182,8 +181,7 @@ public:
 
 private:
     MapData& data;
-
-    TransformState state;
+    TransformState& state;
     FrameData frame;
 
     int indent = 0;