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xelanoimis

horizontal vs vertical fov (again)

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I was reading this post: http://www.gamedev.net/community/forums/topic.asp?topic_id=513623 and I was thinking of an argument for horizontal fov (that is when you fix how much you see on horizontal and let the vertical be adjusted depending on monitor/resolution aspect) Most people incline to let the wide screens see more horizontally (vertical fov). That may be fine with usual 3d games, but if your game has an accent on cinematic cameras (like using a lot cutscenes) it makes more sense to do them in wide screen and for 4:3 monitors to add top and bottom black bars. Isn't this how we all see the wide screen movies? I bump into this issue with Blender which has horizontal fov, while I was using a vertical one. And it didn't like a simple conversion from my fovy to coresponding fovx (based on resolution). Not sure what I missed or if I can do something about it...

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It's funny you mention this...back when the game Bioshock came out people discovered that it had a constant horizontal FOV and increased the vertical FOV when running in 4:3 resolutions. People went absolutely bananas over it...they felt like widescreen users were somehow getting the shaft because 4:3 users could see a tiny bit more. The whole thing was totally ridiculous, and they ended up patching the game to change that.

Anyway I would agree with you and the Bioshock developers: at this point widescreen is becoming more and more prominent, so really games should be made with widescreen in mind and then either add a bit of vertical FOV for 4:3 or use black bars.

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And I finally found my Blender issue :)

First, it was the fovy to fovx conversion, which isn't just
fovx = fovy * width / height
but
fovx = atan( tan(fovy/2) * width / height ) * 2 )
using radians

Second, Blender was showing the render area so small as it seemed at a wrong fov. I had to zoom in (scroll) to realize it's right. I think their zoom in camera view mode affects the fov which along with the mistake in the conversion formula confused me for more than 2 hours, until 5am :(

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>>so really games should be made with widescreen in mind and then either add a bit of vertical FOV for 4:3

thats exactly what the Bioshock guys done, only to get blasted. Even though it was the better choice.

like I said in the other topic for the majority of the 3d games using a fixed horizontal FOV makes more sense due to most of the action happening on the ground plane. This way performance differences between 4:3 + 16:10/16:9 are much less.

This is best illustrated with here, a typical 3d game, the visual difference between the first 2 shots is less important (bit of extra sky/ground) than the last 2.

http://www.gamedev.net/community/forums/mod/journal/journal.asp?jn=450912&cmonth=11&cyear=2008

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