black screen on preview in offline mode

[luckyrawatlucky]

Problem description

when I'm offline and previewing any project then it only shows blank screen as can be seen in attached screenshot.

Attach a .c3p

Steps to reproduce

1. disconnect internet wire from your pc
2. start your PC
3. open construct 3 editor
4. open any demo project.
5. press preview button.

Observed result

No preview

Expected result

preview project

More details

Affected browsers/platforms:

Chrome / Windows

First affected release:

System details

View details

PASTE HERE

[AshleyScirra]

Please make sure your reproduction steps start with:

1. Clear browser cache
2. Load Construct and wait for the "Ready to be used offline" notification to appear
3. Start a preview of an empty project while still online (as preview needs to be cached for use offline separately)
4. Go offline

Then re-test the issue and see if it still occurs.

You did not mention doing 2 or 3, so unless you state otherwise I would assume not doing/waiting for those was the problem.

[luckyrawatlucky]

2 and 3 both were also done.
I worked online for several hours, and did preview project a lot of time in online mode. when I shut the pc and disconnected from internet and started pc again then this blank screen appeared.

[kingpirux]

i also have the same issue, looks like the "Ready to be used offline" is NOT caching all the features, behaviours and plugins.

[AshleyScirra]

I can't reproduce this. No project was provided and the report claims it works with any project so I just used the 'Spell caster' example. I followed these steps:

1. Clear full browser data
2. Launched https://editor.construct.net/r484/
3. Waited for 'Ready to use offline' notification to appear
4. Opened 'Spell caster' project and previewed it, waiting a few seconds to ensure browser caching completes
5. Closed both the preview window and then the editor browser tab
6. Unplugged ethernet network cable from PC, verified other websites do not load with "internet disconnected" message
7. Launched https://editor.construct.net/r484/
8. Opened 'Spell caster' project and previewed it

It still ran the project just fine.

I can never seem to reproduce these reports of offline support not working - I suspect the real cause is not waiting for the browser caching to finish. To be clear, there are two steps you must follow for this to work:

1. Open the editor and wait for the 'Ready to use offline' notification to appear
2. Open any project and preview (as the preview must be separately cached for use offline). You must also wait at least a few seconds - if you preview then close immediately, the preview caching probably did not complete. You can see the caching status in the browser console with the tags [SW-Preview].

(It's unfortunate there are two steps - Construct does try to cache the preview mode when you load the editor, but privacy changes to how browsers store data prevent it being able to do so unless you open preview mode in a separate window.)

My best guess is either anyone affected did not wait for preview to finish caching (e.g. opening and closing the preview window very quickly), or there is something specific to the project being tested that does not work when offline, in which case you need to update your report to provide a specific project (as per the bug report guidelines, which require that to avoid this type of confusion).