[x3d-public] OrthoViewpoint fieldOfView

[Andreas Plesch]

> Date: Fri, 4 May 2018 15:32:48 -0600
> From: GPU Group <gpugroup at gmail.com>
> To: X3D Graphics public mailing list <x3d-public at web3d.org>
> Subject: Re: [x3d-public] OrthoViewpoint fieldOfView
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>         <CAM2ogRc8-11CY6aDyiOYThBiEY4ZnXDU2jfeEnDA-6qcp92W8w at mail.gmail.com>
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>
> Its like a zoom.
> on bind, freewrl checks if fieldOfView.n == 4 and copies, else uses defaults
> then on each frame, it honors the ymax - ymin range (like you say a single
> value would do)
> - and scales the xmax- xmin range to match the aspect ratio of the screen.
> -- this assumes you don't want anisotropic scaling,
> - and treats the field as outputOnly on each frame (in case you want to
> know the range in other nodes)
> - until the next bind when it starts fresh
> -Doug

Thanks.
It is like a zoom, and potentially also like an offset if the min and
max values are not centered on 0.
Always scaling the x range according to the window aspect ratio may
sometimes cut off the requested minimum x range, I believe ?
For example, if the fieldOfView is -10,-1,10,1 , eg. the requested
minimum x range is -10,10, and the window aspect ratio is 1:1, then
scaling the x range would mean cutting it down to -1,1, no ?
So other browsers check if the requested width/height aspect ratio is
larger than the display aspect ratio, and if so rescale the y range,
and if not rescale the x range.

-Andreas