HelixToolkit.UWP.Viewport3DX has memory leaks

[fmExcense]

Hi,

In my app, i'm a using a UserControl which includes a Viewport3DX. This UserControl is attached to the xaml tree and detached from the xaml tree when the user opens it or close it. I'm using a single EffectManager which is shared by all the Viewport3DX instances.

I suspect the Viewport3DX control does not correctly free all its resources when it is detached. For example, binding to Items.CollectionChanged is never unbound when the view is detached. The properties for which a callback are registered are not unregistered. I am using Assimp to import my models. Some MemoryStreams (TextureModel) used by the Viewport3DX (ViewCubeMaterialCore, BillboardText3D) are not disposed once the view is detached.

Can you have a look? Thanks!

[holance]

Could you upload a simple demo for this issue?

[holance]

Are you creating new viewport frequently? After you detach it from the visual tree, you need to manually set its EffectsManager to null (If using binding, set its DataContext to null). Otherwise resources will not be released.

[fmExcense]

Hi holance,

Sorry for the late reply... I tried your suggestion above, but it does not seem to release properly all the resources used by the viewport3DX.

I've made a sample app, which purpose is just to attach and detach a Viewport3DX object. The Viewport3DX detached is never collected by the garbage collector (collector can be called using CTRL+G keys).
All the viewport3DX objects created share the same EffectManager, Geometry3D & Materials objects. So, no new textures are created when creating a new Viewport3DX.
But if you inspect the memory heap, new TextureInfo are created each time a Viewport3DX object is created. MemoryStreams attached to these TextureInfo are not disposed when detaching the Viewport3DX from the scene.

I guess i'm not doing things correctly when detaching the Viewport3DX object... Maybe you can have a quick look at the sample app?

Thanks a lot,
HelixLeaks.zip

[holance]

Let me know if you are still getting leaks.

[fmExcense]

Hi holance,

Thanks for your reply! I've tried my sample app with the develop branch of the helix toolkit repo, where your patch has been merged. When I attach / dettach a viewport3DX, the object is not collected by the garbage collector (see the screenshot belown, 3 viewport3DX were created, none of them was removed by the GC

I do the following to remove my Viewport3DX object:

view3D.Detach(); view3D.Items.Remove(model3d); view3D.Items.Remove(light); view3D.DataContext = null; view3dContainer.Children.RemoveAt(0);

Am i missing something here?

The EffectsManager is not disposed when removing a Viewport3DX. All Viewport3DX objects created share the same EffectManager. The EffectManager is disposed when the user navigates to another Page.

Thanks for your help!

[holance]

I am using following:

                view3D.EffectsManager = null;
                view3D.Items.Clear();
                view3D.DataContext = null;
                view3dContainer.Children.Clear();
                view3D.Dispose();
                view3D = null;
                light = null;
                model3d.Dispose();
                model3d = null;
                GC.Collect(2, GCCollectionMode.Forced);
                GC.Collect(2, GCCollectionMode.Forced);
                GC.WaitForFullGCComplete();

[fmExcense]

Hi holance,

Using your code, it works 👍

Do you plan to include your fix to a 2.18.1 version?

Thanks!

[fmExcense]

Hi holance,

Any chance that you provide a new release with the hotfix for the Viewport3DX leaks soon?

Thanks,

[holance]

Probably early October.