[core] Render from the main thread

Do not create a thread for the MapContext anymore.

include/mbgl/map/map.hpp

@@ -32,10 +32,6 @@ class ShapeAnnotation;
 struct CameraOptions;
 struct AnimationOptions;
 
-namespace util {
-template <class T> class Thread;
-} // namespace util
-
 class Map : private util::noncopyable {
     friend class View;
 
@@ -46,22 +42,15 @@ class Map : private util::noncopyable {
                  ConstrainMode constrainMode = ConstrainMode::HeightOnly);
     ~Map();
 
-    // Pauses the render thread. The render thread will stop running but will not be terminated and will not lose state until resumed.
-    void pause();
-    bool isPaused();
-
-    // Resumes a paused render thread
-    void resume();
-
     // Register a callback that will get called (on the render thread) when all resources have
     // been loaded and a complete render occurs.
     using StillImageCallback = std::function<void (std::exception_ptr, PremultipliedImage&&)>;
     void renderStill(StillImageCallback callback);
 
-    // Triggers a synchronous render.
-    void renderSync();
+    // Main render function.
+    void render();
 
-    // Notifies the Map thread that the state has changed and an update might be necessary.
+    // Notifies the Map that the state has changed and an update might be necessary.
     void update(Update update);
 
     // Styling
@@ -189,7 +178,7 @@ class Map : private util::noncopyable {
 private:
     View& view;
     const std::unique_ptr<Transform> transform;
-    const std::unique_ptr<util::Thread<MapContext>> context;
+    const std::unique_ptr<MapContext> context;
     MapData* data;
 
     enum class RenderState {

include/mbgl/map/view.hpp

@@ -30,44 +30,42 @@ enum MapChange : uint8_t {
 
 class View {
 public:
-    // Called from the main thread directly after initialization. Must always return the same value,
-    // i.e. it may not change over time.
+    virtual ~View() = default;
+
+    // Called directly after initialization. Must always return the same value, i.e. it may
+    // not change over time.
     virtual float getPixelRatio() const = 0;
 
-    // Called from the main thread when the View signaled a dimension change. Must return the
-    // logical dimension of this map in pixels.
+    // Called when the View signaled a dimension change. Must return the logical dimension
+    // of this map in pixels.
     virtual std::array<uint16_t, 2> getSize() const = 0;
 
-    // Called from the main thread for every frame that is being rendered. Must return the absolute
-    // dimensions of the current framebuffer. Typically, this is the logical width scaled by the
-    // pixel ratio, but in case the view was moved to display with a different pixel ratio, it can
-    // also be different from that rule.
+    // Called for every frame that is being rendered. Must return the absolute dimensions of
+    // the current framebuffer. Typically, this is the logical width scaled by the pixel ratio,
+    // but in case the view was moved to display with a different pixel ratio, it can also be
+    // different from that rule.
     virtual std::array<uint16_t, 2> getFramebufferSize() const = 0;
 
-    // Called from the main thread when this View is associated with a Map object.
-    virtual void initialize(Map *map_);
-
-    // Called from the render thread. Makes the GL context active in the current
-    // thread. This is typically just called once at the beginning of the
-    // renderer setup since the render thread doesn't switch the contexts.
+    // Called when this View is associated with a Map object.
+    virtual void initialize(Map*);
+
+    // Called when the view's GL context needs to be made active or inactive. These are called,
+    // as a matched pair, in four situations:
+    //
+    //   1. When releasing GL resources during Map destruction
+    //   2. When calling a CustomLayerInitializeFunction, during Map::addCustomLayer
+    //   3. When calling a CustomLayerDeinitializeFunction, during Map::removeCustomLayer
+    //   4. When rendering for Map::renderStill
+    //
+    // They are *not* called for Map::render; it is assumed that the correct context is already
+    // activated prior to calling Map::render.
     virtual void activate() = 0;
-
-    // Called from the render thread. Makes the GL context inactive in the current
-    // thread. This is called once just before the rendering thread terminates.
     virtual void deactivate() = 0;
 
-    virtual void notify() = 0;
-
-    // Called from the render thread. The implementation must trigger a rerender.
-    // (map->renderSync() from the main thread must be called as a result of this)
+    // Called when the map needs to be rendered; the view should call Map::render() at some point
+    // in the near future. (Not called for Map::renderStill() mode.)
     virtual void invalidate() = 0;
 
-    // Called from the render thread before the render begins.
-    virtual void beforeRender() = 0;
-
-    // Called from the render thread after the render is complete.
-    virtual void afterRender() = 0;
-
     // Reads the pixel data from the current framebuffer. If your View implementation
     // doesn't support reading from the framebuffer, return a null pointer.
     virtual PremultipliedImage readStillImage();

include/mbgl/platform/default/glfw_view.hpp

@@ -22,13 +22,10 @@ class GLFWView : public mbgl::View {
     std::array<uint16_t, 2> getSize() const override;
     std::array<uint16_t, 2> getFramebufferSize() const override;
 
-    void initialize(mbgl::Map *map) override;
+    void initialize(mbgl::Map*) override;
     void activate() override;
     void deactivate() override;
-    void notify() override;
     void invalidate() override;
-    void beforeRender() override;
-    void afterRender() override;
 
     static void onKey(GLFWwindow *window, int key, int scancode, int action, int mods);
     static void onScroll(GLFWwindow *window, double xoffset, double yoffset);

include/mbgl/platform/default/headless_view.hpp

@@ -38,34 +38,31 @@ class HeadlessView : public View {
     std::array<uint16_t, 2> getSize() const override;
     std::array<uint16_t, 2> getFramebufferSize() const override;
 
+    void invalidate() override;
     void activate() override;
     void deactivate() override;
-    void notify() override;
-    void invalidate() override;
-    void beforeRender() override;
-    void afterRender() override;
+
     PremultipliedImage readStillImage() override;
 
-    void resizeFramebuffer();
     void resize(uint16_t width, uint16_t height);
 
 private:
-    void loadExtensions();
-    bool isActive() const;
-
     // Implementation specific functions
     static gl::glProc initializeExtension(const char*);
     void createContext();
     void destroyContext();
     void clearBuffers();
+    void resizeFramebuffer();
     void activateContext();
     void deactivateContext();
 
-private:
     std::shared_ptr<HeadlessDisplay> display;
     const float pixelRatio;
     std::array<uint16_t, 2> dimensions;
+
     bool needsResize = false;
+    bool extensionsLoaded = false;
+    bool active = false;
 
 #if MBGL_USE_CGL
     CGLContextObj glContext = nullptr;
@@ -82,13 +79,9 @@ class HeadlessView : public View {
     GLXPbuffer glxPbuffer = 0;
 #endif
 
-    bool extensionsLoaded = false;
-
     GLuint fbo = 0;
     GLuint fboDepthStencil = 0;
     GLuint fboColor = 0;
-
-    std::thread::id thread;
 };
 
 } // namespace mbgl

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java

@@ -521,7 +521,6 @@ public void onPause() {
         mConnectivityReceiver = null;
 
         mUserLocationView.onPause();
-        mNativeMapView.pause();
     }
 
     /**
@@ -533,7 +532,6 @@ public void onResume() {
         mConnectivityReceiver = new ConnectivityReceiver();
         getContext().registerReceiver(mConnectivityReceiver, new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
 
-        mNativeMapView.resume();
         mNativeMapView.update();
         mUserLocationView.onResume();
 
@@ -1094,9 +1092,7 @@ private List<Marker> getMarkersInBounds(@NonNull LatLngBounds bbox) {
     }
 
     int getTopOffsetPixelsForIcon(Icon icon) {
-        // This method will dead lock if map paused. Causes a freeze if you add a marker in an
-        // activity's onCreate()
-        if (mDestroyed || mNativeMapView.isPaused()) {
+        if (mDestroyed) {
             return 0;
         }
 
@@ -1243,11 +1239,11 @@ public void onDraw(Canvas canvas) {
             return;
         }
 
-        if (mDestroyed || mNativeMapView.isPaused()) {
+        if (mDestroyed) {
             return;
         }
 
-        mNativeMapView.renderSync();
+        mNativeMapView.render();
     }
 
     @Override

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMapView.java

@@ -119,24 +119,12 @@ public void destroySurface() {
         nativeDestroySurface(mNativeMapViewPtr);
     }
 
-    public void pause() {
-        nativePause(mNativeMapViewPtr);
-    }
-
-    public boolean isPaused() {
-        return nativeIsPaused(mNativeMapViewPtr);
-    }
-
-    public void resume() {
-        nativeResume(mNativeMapViewPtr);
-    }
-
     public void update() {
         nativeUpdate(mNativeMapViewPtr);
     }
 
-    public void renderSync() {
-        nativeRenderSync(mNativeMapViewPtr);
+    public void render() {
+        nativeRender(mNativeMapViewPtr);
     }
 
     public void resizeView(int width, int height) {
@@ -515,15 +503,9 @@ private native void nativeCreateSurface(long nativeMapViewPtr,
 
     private native void nativeDestroySurface(long nativeMapViewPtr);
 
-    private native void nativePause(long nativeMapViewPtr);
-
-    private native boolean nativeIsPaused(long nativeMapViewPtr);
-
-    private native void nativeResume(long nativeMapViewPtr);
-
     private native void nativeUpdate(long nativeMapViewPtr);
 
-    private native void nativeRenderSync(long nativeMapViewPtr);
+    private native void nativeRender(long nativeMapViewPtr);
 
     private native void nativeViewResize(long nativeMapViewPtr, int width, int height);
 

platform/android/src/jni.cpp

@@ -404,39 +404,18 @@ void nativeDestroySurface(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr
     nativeMapView->destroySurface();
 }
 
-void nativePause(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr) {
-    mbgl::Log::Debug(mbgl::Event::JNI, "nativePause");
-    assert(nativeMapViewPtr != 0);
-    NativeMapView *nativeMapView = reinterpret_cast<NativeMapView *>(nativeMapViewPtr);
-    nativeMapView->pause();
-}
-
-jboolean nativeIsPaused(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr) {
-    mbgl::Log::Debug(mbgl::Event::JNI, "nativeIsPaused");
-    assert(nativeMapViewPtr != 0);
-    NativeMapView *nativeMapView = reinterpret_cast<NativeMapView *>(nativeMapViewPtr);
-    return nativeMapView->getMap().isPaused();
-}
-
-void nativeResume(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr) {
-    mbgl::Log::Debug(mbgl::Event::JNI, "nativeResume");
-    assert(nativeMapViewPtr != 0);
-    NativeMapView *nativeMapView = reinterpret_cast<NativeMapView *>(nativeMapViewPtr);
-    nativeMapView->resume();
-}
-
 void nativeUpdate(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr) {
     mbgl::Log::Debug(mbgl::Event::JNI, "nativeUpdate");
     assert(nativeMapViewPtr != 0);
     NativeMapView *nativeMapView = reinterpret_cast<NativeMapView *>(nativeMapViewPtr);
     nativeMapView->getMap().update(mbgl::Update::Repaint);
 }
 
-void nativeRenderSync(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr) {
-    mbgl::Log::Debug(mbgl::Event::JNI, "nativeRenderSync");
+void nativeRender(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr) {
+    mbgl::Log::Debug(mbgl::Event::JNI, "nativeRender");
     assert(nativeMapViewPtr != 0);
     NativeMapView *nativeMapView = reinterpret_cast<NativeMapView *>(nativeMapViewPtr);
-    nativeMapView->getMap().renderSync();
+    nativeMapView->render();
 }
 
 void nativeViewResize(JNIEnv *env, jni::jobject* obj, jlong nativeMapViewPtr, jint width, jint height) {
@@ -1815,11 +1794,8 @@ extern "C" JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved) {
         MAKE_NATIVE_METHOD(nativeTerminateContext, "(J)V"),
         MAKE_NATIVE_METHOD(nativeCreateSurface, "(JLandroid/view/Surface;)V"),
         MAKE_NATIVE_METHOD(nativeDestroySurface, "(J)V"),
-        MAKE_NATIVE_METHOD(nativePause, "(J)V"),
-        MAKE_NATIVE_METHOD(nativeIsPaused, "(J)Z"),
-        MAKE_NATIVE_METHOD(nativeResume, "(J)V"),
         MAKE_NATIVE_METHOD(nativeUpdate, "(J)V"),
-        MAKE_NATIVE_METHOD(nativeRenderSync, "(J)V"),
+        MAKE_NATIVE_METHOD(nativeRender, "(J)V"),
         MAKE_NATIVE_METHOD(nativeViewResize, "(JII)V"),
         MAKE_NATIVE_METHOD(nativeFramebufferResize, "(JII)V"),
         MAKE_NATIVE_METHOD(nativeAddClass, "(JLjava/lang/String;)V"),