Raycast() Crash [Solved]

Edit: Solved since merging latest master.

Hello, I’m calling Raycast() twice, the first time is fine, the second it crashes. The first time is with one scene, the second with a different scene. I don’t think the second scene has problems because if I cast the first time with the second scene it doesn’t crash. Relavent snippets:

Variable init stuff:


	//Load scene.


	File loadFile(context_,main->filesystem_->GetProgramDir()
			+ "Data/Scenes/solcommCity.xml", FILE_READ);

	main_->cameraNode_ = main_->scene_->GetChild("RavenMech")->GetChild("camera");

	//Load moveButt scene.

	scene_ = new Scene(main_->GetContext());
	cameraNode_ = new Node(main_->GetContext());

	File loadFile2(context_,main->filesystem_->GetProgramDir()
			+ "Data/Scenes/moveButts.xml", FILE_READ);

	cameraNode_ = scene_->GetChild("camera");

crash happens below:

	Ray cameraRay = cameraNode_->GetComponent<Camera>()->GetScreenRay(
			(float) eventData[P_X].GetInt() / main_->graphics_->GetWidth(),
			(float) eventData[P_Y].GetInt() / main_->graphics_->GetHeight());

	PODVector<RayQueryResult> results;

	RayOctreeQuery query(results, cameraRay, RAY_TRIANGLE, 1000.0f,

	cameraRay = main_->cameraNode_->GetComponent<Camera>()->GetScreenRay(
				(float) eventData[P_X].GetInt() / main_->graphics_->GetWidth(),
				(float) eventData[P_Y].GetInt() / main_->graphics_->GetHeight());
	query.ray_ = cameraRay;
	main_->scene_->GetComponent<Octree>()->Raycast(query); //CRASH

Where exactly does it crash? (you may need to run in debug mode)

Does it still crash if you disable worker threads? (-nothreads command line option, or engine startup parameter WorkerThreads = false)

engineParameters_[“WorkerThreads”] = false; didn’t work. It crashes at main_->scene_->GetComponent()->Raycast(query); //CRASH

Have you created an octree component in the scene root ?

Like so for example:


If that’s the exact point of crash, and not some function inside the Octree class, then I recommend nullchecking the whole chain of objects you’re accessing. Has something caused the Octree to be destroyed at the point when you call Raycast?

I’m not touching the octree, the only things I’m modifying are on the lines “results.Clear();” , “cameraRay = …” and “query.ray_ = cameraRay;” . gdb backtrace: pastebin.com/NZ7jtp0H

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb795db40 (LWP 2397)]
0x08521ffc in Urho3D::Renderer2D::ProcessRayQuery(Urho3D::RayOctreeQuery const&, Urho3D::PODVector<Urho3D::RayQueryResult>&) ()
(gdb) backtrace
#0  0x08521ffc in Urho3D::Renderer2D::ProcessRayQuery(Urho3D::RayOctreeQuery const&, Urho3D::PODVector<Urho3D::RayQueryResult>&) ()
#1  0x08215085 in Urho3D::RaycastDrawablesWork(Urho3D::WorkItem const*, unsigned int) ()
#2  0x08401350 in Urho3D::WorkQueue::ProcessItems(unsigned int) ()
#3  0x08402b6f in Urho3D::WorkerThread::ThreadFunction() ()
#4  0x081f9ecf in Urho3D::ThreadFunctionStatic(void*) ()
#5  0xb7fa4f70 in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#6  0xb7ce8bee in clone () from /lib/i386-linux-gnu/libc.so.6

Renderer2D is the component that handles the collective rendering and raycasting for Urho2D drawables. Do you have 2D sprites in your scene, and do you manipulate them (disable/enable them, or remove from the scene) before the raycast? There can be issues with managing the drawable list in the Renderer2D code: possible double-addition etc.

The ideal would be if you can make a reproduction case that uses nothing but Urho built-in assets and submit as a github issue.

Yes I have a 2d sprite in the middle of the screen (the player). Disabling before the raycast and re-enabling after the raycast stopped the crash. This is a problem because I plan on having hundreds of sprites onscreen and can’t be doing that then.

I committed a possible null exception fix in the master branch (Drawable2D material may be null and used in sorting before it’s assigned by frame update.) Check if that fixes the issue.

Thanks, I don’t know what magical spell you cast but after merging with the latest master, no more crash. If this issue pops up again, I’ll update the thread.