On Hoard I used a matrix with shear in it to help fake a 2D style "top-down" view where you can see the fronts of objects. Zelda: A Link Between Worlds does something similar. These effects are bit subtle than what you seem to be asking for though.
Yeah, a lil too subtle, but a good trick nevertheless.
Btw; Are you still working on this one game you've posted images about ages
ago? Or do I miss something?
Try a while-loop for the sake of it.
... I've no idea if it's the fastest, but i'm using a simple quad with a texture on it for my sprites and a simple opengl shader. It's more then enough for my needs and there's a lot of optimizations I can do.
Good old OpenGL trick, rendering a sceen-aligned quad with a texture.
Someone using any Vulkan implementation on iOS already?
I may be completely wrong, but didn't Chronicles of Riddick: Escape from Butcher Bay do something like this? If I understand your question correctly AND remember well (lots of assumptions there!), crouching in that game turned your FOV into a "fish eye" mode that allowed to better survey your surroundings, at least in theory. I remember it mostly because it made me so queasy it was damn near unplayable for me, I'm afraid :-/ Went through most of the game crouching as little as possible, and every time I've tried to replay it since, I go up until I need to crouch and go "ooh.. yeah..." and have to turn it off. That's too bad, because the effect is otherwise interesting! I don't know if it was an actual difference in projection, or if they just widened the FOV to ridiculous amounts, either, but that's the one example that comes to mind right now. Will keep going back through the mental archives!
Last minute edit: wasn't the drone control in Perfect Dark using a fish-eye mode as well?
Checked Riddick. Uhh, no, that's ugly. That's not a fisheye. It's simply an
increase of the field of view under standard perspective projection making
the sides stretching away much stronger. Such an enlargement of the field of
view should only be used for a brief moment, like for some effects (as it's
done in racing games for example when boosting etc.). About the other game,
I can't find any video of controlling the drone. Some reference?
The point with the fisheye is that the distortions produced under a larger
fov are more acceptable. Regarding fisheyes, there is another idea in my
mind. A fisheye lens usually covers up to 180 degrees, but mathematically
there is nothing from stopping you implementing a >180 degree one, even up
to 360 degrees. Giving the extrem case, i.e. the 360 degree one, you can see
the world behind you as well, hence the entire world. I ask myself if there
is gameplay hidden in there?