Add support for ortographic projection

[mrdeveloperdude]

As a user of f3d I would like to see support for orthographic projection.

Currently only perspective projection is supported. My use case is that I will render thumbnails of CAD models and it is customary to use orthographic projection in CAD.

It can possibly be faked by moving the camera far away and setting a low camera angle. Possible pitfalls of this hack is floating point precision problems, poor z-buffer dynamic range use and more.

[mwestphal]

Indeed a nice addition, shouldnt be too hard to add.

[Meakk]

For reference if someone wants to give it a try: https://vtk.org/doc/nightly/html/classvtkCamera.html#a87b276a44eb1817aa388c89dc9becfc5

Obviously we need an option to toggle it.

[aemreaydin]

I'd like to work on this as my first issue. I'm trying to write a simple Vulkan Engine as a hobby project and would love to work on f3d as well to learn more about graphics systems going forward!

[mwestphal]

Hi @aemreaydin !

You are very welcome! We have been discussing this issue on discord, did you join already ?

https://discord.f3d.app

[Meakk]

There's a draft by @lknknm done here #942 if you want to take over.

[mwestphal]

@kidharb so do you wanna try your hand at this one ?

[kidharb]

Yes, I'm just not sure regarding how the baselines work. So I've been trying to run the ctests locally which has led me down a path of learning cmake. Should I just push the code, which is just aemreaydin code?

[mwestphal]

As you prefer, let me know if you need any help understanding how it works.

[mwestphal]

Partially addresed by #1235

[mwestphal]

Still need a command line option, are you will to add it @kidharb ?

[mwestphal]

Fixed by #1315