Sokol: Imgui integration issues with decoupled systems

[septag]

I'm trying to integrate sokol imgui debugger.
My design is very plugin based and decoupled. For example, imgui and all of it's drawing components are provided as a plugin. the core engine presents the sokol api (a structure like hooks) to the plugins.
The problem is sokol_gfx_imgui is very tightly coupled with sokol_gfx implementation (which I don't think it should be) and wants to access it's internal data. I can do workarounds for other stuff and install hooks and hack sg_install_trace_hooks inside sokol_gfx_imgui.h to point to my host app sokol_gfx.
But still remains all the _sg. state access inside the file.

Now I have to change all _sg references in the header to a _sg_state_t pointer that I pass to the plugin. which is not very elegant.

I suggest sokol_gfx_imgui moves to a more decoupled state where optionally it can receive a custom hook instead of calling sg_install_trace_hooks itself. and maybe receive a custom void* instead of _sg variable ?
because type declerations isn't that big of a problem, right now I'm including SOKOL_IMPL + sokol_gfx.h with SOKOL_DUMMY as the backend, so it can define it's internal structures and whatnot.

Thanks

EDIT: oh, I just realized that defining SOKOL_DUMMY_BACKEND for plugin implementation doesn't work, because their internal structures are different

[floooh]

Yeah, my intent was that sokol_gfx_imgui.h is an extension header, and must be included in the the same compilation unit as the sokol_gfx.h implementation (and thus has direct access to the internal _sg variable).

Providing a void* wouldn't help, because sokol_gfx_imgui.h also must know the private structure declarations which only exist in the sokol_gfx.h implementation.

Letting sokol_gfx_imgui.h only depend on the sokol_gfx.h implementation should be possible, but I need to add functions to sokol_gfx.h to query some setup parameters (at least the resource pool sizes, maybe a couple other things as well).

[septag]

Cool.
there is also couple of stuff I'm experimenting with decoupling, like for example if sokol_gfx is initialized and submitted some commands (creating some objects) before sokol_imgui initialization. They are obviously not recorded inside imgui, thus some information are not available to sokol_imgui, that may cause some problems like crashes (I got one assertion in _sg_imgui_draw_uniforms_panel)

So I guess they have to be tagged or something similiar so sokol_imgui will be aware that they have missing data.

[floooh]

...I think I have removed most accesses to sokol_gfx.h internal structs and functions, still WIP, I haven't tested compiling sokol_gfx_imgui.h without the sokol_gfx.h implementation included before it, but it should be pretty close.

I have removed the sg_query_*_state() and sg_query_buffer_overflow() functions from the trace callbacks, because those functions are now called from sg_gfx_imgui.h, and since they don't change state in sokol_gfx.h they're not really relevant for debugging, so removing them from the 'trace-set' was the most simple solution for now. I'll finish up the work in the next couple of days (mainly testing and updating the docs).

[floooh]

...ok, a few final fixes, and now it works, I have changed the sokol-samples accordingly, sokol_gfx_imgui.h now only needs the sokol_gfx.h declaration included in front, not the implementation (and imgui.h of course).

I'll keep the ticket open until I have updated the documentation.

[floooh]

...all done now, since sokol_gfx_imgui.h is a "normal" util header now I have moved it to the util directory (I also changed the SOKOL_IMPL define to SOKOL_GFX_IMGUI_IMPL, planning to use separate defines for the util headers).

[septag]

awesome! I've just merged it with my code and removed the sokol impl completely from my plugin. working as intended.

Thank you!