When rendering canvas is quite big, 3D drawing area is cropped at half the size of the canvas

[Vousk-prod.]

Hi everyone !

I've just noticed that when the rendering canvas size is quite big, above a certain size the 3D drawing area is suddenly cropped (to half the size of the rendering canvas, it seems).

If you lower the width of the canvas, the height limit increases, and vice versa. And a strange fact: critical values are different depending on the context.

Here are some cases (on my computer, values may differ on yours)

- On a simple web page:

3500px x 1024px : ok
3500px x 1025px (and above) : cropped
3637px x 1024px : ok
3638px (and above) x 1024px : cropped

I tried to reproduce that on the PG, and the values are not the same:

3500px x 2368px : ok
3500px x 2369px (and above) : cropped
3536px x 2368px : ok
3537px (and above) x 2368px : cropped

The width around 3500 is an arbitrary value, you can put quite more if height is low enough (and vice versa).

I don't know if the values will be different on your devices, but you can test that with this PG : http://www.babylonjs-playground.com/#17HUVT#1

Is it expected behavior or a bug ?

[Vousk-prod.]

The bug mentionned above seems to happen only on FF. On Chrome the drawing area is not cropped, but above a certain size, there is no 3D at all.

[GameMonetize]

So this is for FF bugzilla

[Vousk-prod.]

Yep, that would make sense, but there is also the fact that if we resize canvas without calling engine.resize(), the bug does not occur (but of course the 3d is then very pixelated).

I can't manage to reproduce it on the playground, I presume the PG environment automatically call engine.resize if changes in the layout are detected, I cannot bypass that to test more deeply.

[GameMonetize]

Firefox developers are really fast to fix and comment on bugs. I did it recently for a shader bug and they had it fixed in a couple of days

[Vousk-prod.]

It depends... january 2015, when we had a bug in FF with instanced multisubmaterials meshes, it took almost a year for them to consider and debug...

[GameMonetize]

Ping me on twitter with the bug if you feel it is slow to fix, we will circle back some FF developers

[Vousk-prod.]

To submit to bugzilla I need more info. Can I bypass engine resizing in the PG ? Is there a particular process that can be involved in cropped 3d area (maybe camera viewport related) when engine resizing is called ?

[GameMonetize]

i would recommend to not use the PG but either to publish a simple page with a simple scene that highlights the problem

[Vousk-prod.]

@Deltakosh

I've created the test page for bugzilla, but before posting I'd like you to test something.

I noticed that the bug occurs only if engine.resize is called. So I've added a button to de/activate that, but I'm asking if I should remove this button or not. Maybe it could be disturbing for them to debug, or they could say that it is BJS related and not browser related.

What do you think ?

[GameMonetize]

Yeah I agree we should be sure that they focus on the bug. You should remove the button

[Vousk-prod.]

Ok, I will remove it.

But it still is strange, why this does not occur if engine is not resized. Do you have any clue?

[GameMonetize]

Not really...And we should not give them hints because it could drive them in a wrong direction

[Vousk-prod.]

OK.

Issue opened : https://bugzilla.mozilla.org/show_bug.cgi?id=1338704