display: fix crash when removing DisplayRegion in pipelined render

Maybe not a perfect solution; we should consider keeping the DisplayRegions around until they have gone through the entire pipeline.

Fixes #427

panda/src/display/graphicsEngine.cxx

@@ -753,7 +753,7 @@ render_frame() {
         // frames, so we won't have to recompute it each frame.
         int num_drs = win->get_num_active_display_regions();
         for (int i = 0; i < num_drs; ++i) {
-          DisplayRegion *dr = win->get_active_display_region(i);
+          PT(DisplayRegion) dr = win->get_active_display_region(i);
           if (dr != nullptr) {
             NodePath camera_np = dr->get_camera(current_thread);
             if (!camera_np.is_empty()) {
@@ -1359,7 +1359,7 @@ is_scene_root(const PandaNode *node) {
     if (win->is_active() && win->get_gsg()->is_active()) {
       int num_display_regions = win->get_num_active_display_regions();
       for (int i = 0; i < num_display_regions; i++) {
-        DisplayRegion *dr = win->get_active_display_region(i);
+        PT(DisplayRegion) dr = win->get_active_display_region(i);
         if (dr != nullptr) {
           NodePath camera = dr->get_camera();
           if (camera.is_empty()) {
@@ -1435,7 +1435,7 @@ cull_and_draw_together(GraphicsEngine::Windows wlist,
 
         int num_display_regions = win->get_num_active_display_regions();
         for (int i = 0; i < num_display_regions; i++) {
-          DisplayRegion *dr = win->get_active_display_region(i);
+          PT(DisplayRegion) dr = win->get_active_display_region(i);
           if (dr != nullptr) {
             cull_and_draw_together(win, dr, current_thread);
           }
@@ -1539,7 +1539,7 @@ cull_to_bins(GraphicsEngine::Windows wlist, Thread *current_thread) {
       PStatTimer timer(win->get_cull_window_pcollector(), current_thread);
       int num_display_regions = win->get_num_active_display_regions();
       for (int i = 0; i < num_display_regions; ++i) {
-        DisplayRegion *dr = win->get_active_display_region(i);
+        PT(DisplayRegion) dr = win->get_active_display_region(i);
         if (dr != nullptr) {
           PT(SceneSetup) scene_setup;
           PT(CullResult) cull_result;
@@ -1659,7 +1659,7 @@ draw_bins(const GraphicsEngine::Windows &wlist, Thread *current_thread) {
           }
           int num_display_regions = win->get_num_active_display_regions();
           for (int i = 0; i < num_display_regions; ++i) {
-            DisplayRegion *dr = win->get_active_display_region(i);
+            PT(DisplayRegion) dr = win->get_active_display_region(i);
             if (dr != nullptr) {
               do_draw(win, gsg, dr, current_thread);
             }

panda/src/display/graphicsOutput.cxx

@@ -697,9 +697,6 @@ void GraphicsOutput::
 remove_all_display_regions() {
   LightMutexHolder holder(_lock);
 
-  CDWriter cdata(_cycler, true);
-  cdata->_active_display_regions_stale = true;
-
   TotalDisplayRegions::iterator dri;
   for (dri = _total_display_regions.begin();
        dri != _total_display_regions.end();
@@ -713,6 +710,12 @@ remove_all_display_regions() {
   }
   _total_display_regions.clear();
   _total_display_regions.push_back(_overlay_display_region);
+
+  OPEN_ITERATE_ALL_STAGES(_cycler) {
+    CDStageWriter cdata(_cycler, pipeline_stage);
+    cdata->_active_display_regions_stale = true;
+  }
+  CLOSE_ITERATE_ALL_STAGES(_cycler);
 }
 
 /**
@@ -740,13 +743,8 @@ set_overlay_display_region(DisplayRegion *display_region) {
  */
 int GraphicsOutput::
 get_num_display_regions() const {
-  determine_display_regions();
-  int result;
-  {
-    LightMutexHolder holder(_lock);
-    result = _total_display_regions.size();
-  }
-  return result;
+  LightMutexHolder holder(_lock);
+  return _total_display_regions.size();
 }
 
 /**
@@ -1504,13 +1502,15 @@ do_remove_display_region(DisplayRegion *display_region) {
     find(_total_display_regions.begin(), _total_display_regions.end(), drp);
   if (dri != _total_display_regions.end()) {
     // Let's aggressively clean up the display region too.
-    CDWriter cdata(_cycler, true);
     display_region->cleanup();
     display_region->_window = nullptr;
     _total_display_regions.erase(dri);
 
-    cdata->_active_display_regions_stale = true;
-
+    OPEN_ITERATE_ALL_STAGES(_cycler) {
+      CDStageWriter cdata(_cycler, pipeline_stage);
+      cdata->_active_display_regions_stale = true;
+    }
+    CLOSE_ITERATE_ALL_STAGES(_cycler);
     return true;
   }
 

panda/src/display/graphicsOutput.h

@@ -394,6 +394,7 @@ protected:
   typedef CycleDataLockedReader<CData> CDLockedReader;
   typedef CycleDataReader<CData> CDReader;
   typedef CycleDataWriter<CData> CDWriter;
+  typedef CycleDataStageWriter<CData> CDStageWriter;
 
 protected:
   int _creation_flags;