add cleanup call for destroying framebuffers

include/llmr/map/map.hpp

@@ -42,6 +42,9 @@ public:
     // Forces a map update: always triggers a rerender.
     void update();
 
+    // Triggers a cleanup that releases resources.
+    void cleanup();
+
     // Controls buffer swapping.
     bool needsSwap();
     void swapped();
@@ -104,6 +107,7 @@ private:
     // uv async callbacks
     static void render(uv_async_t *async);
     static void terminate(uv_async_t *async);
+    static void cleanup(uv_async_t *async);
     static void delete_async(uv_handle_t *handle);
 
     // Setup
@@ -163,6 +167,7 @@ private:
     uv_thread_t thread;
     uv_async_t *async_terminate = nullptr;
     uv_async_t *async_render = nullptr;
+    uv_async_t *async_cleanup = nullptr;
 };
 
 }

include/llmr/renderer/painter.hpp

@@ -50,6 +50,13 @@ public:
 
 
     void setup();
+
+    // Perform cleanup tasks that prepare shutting down the app. This doesn't mean that the
+    // app will be shut down. That means all operations must be automatically be reversed (e.g. through
+    // lazy initialization) in case rendering continues.
+    void cleanup();
+
+
     void clear();
 
     // Updates the default matrices to the current viewport dimensions.

src/map/map.cpp

@@ -53,6 +53,10 @@ void Map::start() {
     uv_async_init(loop, async_render, render);
     async_render->data = this;
 
+    async_cleanup = new uv_async_t();
+    uv_async_init(loop, async_cleanup, cleanup);
+    async_cleanup->data = this;
+
     uv_thread_create(&thread, [](void *arg) {
         Map *map = static_cast<Map *>(arg);
         map->run();
@@ -67,6 +71,8 @@ void Map::stop() {
     async_terminate = nullptr;
     uv_close((uv_handle_t *)async_render, delete_async);
     async_render = nullptr;
+    uv_close((uv_handle_t *)async_cleanup, delete_async);
+    async_cleanup = nullptr;
 
     // Run the event loop once to make sure our async delete handlers are called.
     uv_run(loop, UV_RUN_ONCE);
@@ -112,6 +118,17 @@ void Map::swapped() {
     rerender();
 }
 
+void Map::cleanup() {
+    uv_async_send(async_cleanup);
+}
+
+void Map::cleanup(uv_async_t *async) {
+    Map *map = static_cast<Map *>(async->data);
+
+    map->view.make_active();
+    map->painter.cleanup();
+}
+
 void Map::render(uv_async_t *async) {
     Map *map = static_cast<Map *>(async->data);
 

src/renderer/painter.cpp

@@ -21,7 +21,7 @@ Painter::Painter(Map &map)
 }
 
 Painter::~Painter() {
-    clearFramebuffers();
+    cleanup();
 }
 
 bool Painter::needsAnimation() const {
@@ -75,6 +75,10 @@ void Painter::setupShaders() {
     compositeShader = std::make_unique<CompositeShader>();
 }
 
+void Painter::cleanup() {
+    clearFramebuffers();
+}
+
 void Painter::resize() {
     const TransformState &state = map.getState();
     if (gl_viewport != state.getFramebufferDimensions()) {