SDLPP: Add scene pause function

sdlpp/sdlpp_scene.cpp

@@ -90,6 +90,9 @@ Scene::getObjects( const std::unordered_set< int > &objectIDs ) {
     return ret;
 }
 void Scene::updateScene() {
+    if(paused) {
+        return;
+    }
     // check for objects that should be removed
     checkKilled();
     std::lock_guard< std::mutex > lock( render_mutex );
@@ -102,6 +105,14 @@ void Scene::updateScene() {
     }
     prev_ticks = now_ticks;
 }
+void Scene::pauseScene() {
+    paused = true;
+    diff_ticks = SDL_GetTicks() - prev_ticks;
+}
+void Scene::unpauseScene() {
+    paused = false;
+    prev_ticks = SDL_GetTicks() - diff_ticks;
+}
 std::vector< std::pair< uint64_t, std::shared_ptr< RenderObject > > >
 Scene::getCollisions( RenderObject &r ) {
     if ( r.getHidden() )

sdlpp/sdlpp_scene.hpp

@@ -28,6 +28,8 @@ public:
     std::vector< std::shared_ptr< RenderObject > >
     getObjects( const std::unordered_set< int > &objectIDs );
     void updateScene();
+    void pauseScene();
+    void unpauseScene();
     std::vector< std::pair< uint64_t, std::shared_ptr< RenderObject > > >
     getCollisions( RenderObject &r );
     void visitCollisions( RenderObject &r, Visitor &v );
@@ -63,12 +65,14 @@ private:
     std::shared_ptr< Renderer > renderer;
     std::shared_ptr< Texture > background;
     int prev_ticks = 0;
+    int diff_ticks = 0;
     std::shared_ptr< RenderObject > leftmost_obj;
     std::shared_ptr< RenderObject > rightmost_obj;
     uint64_t max_object_id = 0;
     std::mutex render_mutex;
     std::unordered_set<uint64_t> background_ids;
     uint64_t first_non_background_index = 1;
+    bool paused = false;
 };
 } // end of namespace SDLPP
 #endif