Add support for ImGui v1.92.0

[jacogasp]

With version v1.92.0, ImGui introduced the RenderHasTexture backend flag to enable backend to render fonts as raw textures. The current ImGui-SFML backend implementation does not support this feature and minimal examples don't run because of failing assertions.

This commit provide support for the new RenderHasTexture backend flag while supporting previous version using the IMGUI_VERSION_NUM macro.

Inspired by #336 and #330

[lapinozz]

I don't think I like the idea of supporting two API for imgui-sfml itself at the same time.
I'd rather we find a way to keep the same API or just deprecate the old version if we have to

[lapinozz]

Maybe there's a way to emulate the new API for imgui < 1.92
Since the new version always loads the default font we could get rid of that parameter and always load the font in the old version too
Maybe there's a way to detect stale font texture so the user doesn't have to manually call the UpdateFontTexture function?

[lapinozz]

Here's what I came up with. It works with ImGui < 1.92 but it has the same API and behaviour as ImGui >= 1.92
master...lapinozz:imgui-sfml:imgui-1.92

[jacogasp]

Hello @lapinozz,

thank you for having a look to the PR. Yea, also to me is not very elegant the usage of the macro to check ImGui version, it makes it a little cumbersome in the sake of backward compatibility. Actually I don't have an opinion on dropping entirely support for ImGui < 1.92.
Anyway, your changes to support all versions look good to me.

[milipili]

Just to inform that at least on MacOS it is currently not working great.
When using latest sfml-imgui on MacOS via vcpkg, fonts are no longer working and it crashes when quitting.
The UpdateFontTexture() requires changes of course (actually simply removed)

However those version in vcpkg work flawlessly

• imgui:arm64-osx@1.91.9
• imgui-sfml:arm64-osx@3.0#1

[lapinozz]

I think the version on vcpkg has some code changed applied, hopefully once everything is figured out those should be removed

The fonts are not working even with ImGui 1.91?

[jacogasp]

Just to inform that at least on MacOS it is currently not working great.

When using latest sfml-imgui on MacOS via vcpkg, fonts are no longer working and it crashes when quitting.

The UpdateFontTexture() requires changes of course (actually simply removed)

However those version in vcpkg work flawlessly

• imgui:arm64-osx@1.91.9

• imgui-sfml:arm64-osx@3.0#1

Yes I confirm that the vcpkg port does not work because of a patch that insert a bug in UpdateFontTexture. For making this work, I added a custom overlay that does not contain the patch and points to my fork. I added some details here.

I tested on macOS arm.