Camera Len’s FOV Changes When Switching Between Applications about panda3d HOT 6 OPEN

Looks like a feature, not a bug: You're using ShowBase. Have you tried base.setAspectRatio(ar) instead of manipulating the Lens directly?

Sets the global aspect ratio of the main window. Set it to None to restore automatic scaling.

I'm not sure what you'd like to do: Set the aspect ratio of the camera out of sync from the window aspect ratio? You can also remove the window-event that is being created by ShowBase and implement your own instead. https://github.com/panda3d/panda3d/blob/4c2581a4d2831eb220ab03757051dc2b372bead9/direct/src/showbase/ShowBase.py#L579C1-L579C1

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I'll note that this behaviour doesn't seem to appear for me, under Ubuntu Linux (specifically, 18.04.6); it may thus be Mac-specific. (Presuming that it doesn't appear under Windows, of course.)

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@kamgha What I'm trying to do is represent a real camera and do some calculations. When the FOV changes, it changes my calculations. I want the window to be an exact representation of what the camera should see.

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@ArsThaumaturgis Thanks for trying it on Ubuntu Linux. I'm planning to try it on windows to see if it is just a macOS problem. I'll update about this.

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Normally ShowBase automatically adjusts the aspect ratio on any window-event, which includes window resizing but evidently also ⌘ + Tab.

To disable the default aspect ratio adjustment:

        self.setAspectRatio(self.getAspectRatio())

Or maybe:

    def adjustWindowAspectRatio(self, aspectRatio):
        pass

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Hi @asmsulaiman , I find your report confusing. You have now renamed it and silently altered the initial description and your code sample! You were mentioning aspect ratio at first, now you mention FOV only. I've augmented your code with the scenery from the tutorial, to see it in action:

        self.scene = self.loader.loadModel("models/environment")
        self.scene.reparentTo(self.render)
        self.scene.setScale(0.25, 0.25, 0.25)
        self.scene.setPos(-8, 42, 0)

On Windows, there is no visible change in FOV. Something can be observed in macOS with your code, but this is due to the window-event from ShowBase being triggered around the creation of the window on Windows (but later on macOS).

It looks like your calculation is wrong: Change to w=32 in your new/current code sample to match to the default window-size of 800x600.

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