[Interest] [Qt3D] What are active render targets for a ScreenRayCaster?

Mike Krus mike.krus at kdab.com
Thu Mar 28 14:35:01 CET 2019


Hi Volker

if I remember correctly, ray casting will apply to all enabled surfaces. It’ll ignore off screen surfaces and surfaces where the cursor is outside the render area. I think it also ignores surfaces when an orthographic camera is used.

So in your case sounds like you should only get a single hit in the main area, and two when testing in the render areas.

5.13 is introducing a QNoPicking frame graph node to explicitly disable picking and ray casting on portions of the frame graph.
 
If you continue having issues with this, please create a JIRA ticket, ideally with a small example.

Regards,
Mike

> On 28 Mar 2019, at 11:13, Volker Enderlein <volker.enderlein at ifm-chemnitz.de> wrote:
> 
> Hi,
> 
> The KDAB article https://www.kdab.com/new-in-qt-3d-5-11-generalized-ray-casting/ states that the ScreeenRayCast test is performed for every active render target. I just stumbled over the question what an active render target is considered for a ScreenRayCaster.
> 
> My FrameGraph contains an orthographic background viewport/camera, a SceneGraph viewport/camera and an orthographic overlay viewport/camera that fill the entire normalized viewport.
> 
> Additionally two smaller viewport/camera exist at the bottom of the window for an axis gnomon and a fps counter.
> 
> When triggering a ScreenRayCaster test with the current mouse position the hitsChanged signal is emitted multiple times with different hits.
> 
> Traversing the scenegraph upwards from the hitted entity (mostly a DistanceFieldTextRenderer is hit) leads me to entities that let me doubt on the returned hit.
> 
> 
> Anyone out there who can shed some light on it? Thanks in advance.
> 
> 
> Cheers, Volker
> 
> -- 
> 
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—
Mike Krus | mike.krus at kdab.com | Senior Software Engineer
KDAB (UK) Ltd., a KDAB Group company
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