bit_user :
cryoburner :
with a smooth curve rather than uneven angles.
Curved monitors will have distortion that's more difficult to compensate for, whereas images on angled monitors can be accurately projected, assuming the monitor aspects and angles are accurately specified. In practice, I don't know how many games actually support this.
The distortion is actually easier to compensate for than with a flat monitor. When a game renders an image using a flat viewport (rectilinear), properly displaying that image requires not just a flat screen, but also for that screen to be at the right distance from your eyes. We regularly ignore that second condition. That's why wide-angle photos look like they're distorted.
https://img00.deviantart.net/fe90/i/2013/132/d/0/wide_angle_distortion__by_samvn-d65204h.jpg
https://i.imgur.com/h6eKRfq.jpg
They're not really distorted, you're just looking at them from the incorrect distance. If you were to put those photos a few inches from your face, they would look correct. This is why games look more distorted when you increase the angular width of the viewport. You're not just supposed to increase the angular width so you can see more. You're also supposed to move the monitor closer so its
real angular width matches the
virtual angular width of the rendering viewport.
So properly displaying images (eliminating distortion) on a 3-flat monitor setup requires (1) the monitors be placed at the proper distance for the image being rendered, (2) the monitors to be oriented correctly (pointed right at your eye), and (3) the game to render the two side viewports at the same angle as which those monitors are canted on your desk.
Properly displaying an image on a curved monitor is actually easier. Instead of a flat viewport (rectilinear - straight lines remain straight, but circles get deformed into ovals near the corners), you use a curved viewport (fisheye - angular width of objects remain the same regardless of location in viewport so circles remain circles, straight lines get curved but the curvature of the monitor cancels that out). The only thing that's required to support it is for the game to know the angular field of view the monitor presents (and of course for you to be sitting in the right spot for the monitor to actually cover that field of view).
But as you said, I don't know of any games which give you this type of control over the viewport. That's not to say it couldn't be done - it'd be trivial to do it since it's just math the GPU is doing anyway. Just that until it's supported, we're stuck projecting rectilinear images onto curved monitors, resulting in unnecessary distortion.