Examples: DirectX9: Force a redraw in the resize loop

[learn-more]

In the Windows examples, currently Dear ImGui does not redraw while resizing the window.
This is caused by the DispatchMessage function running it's own message loop as long as the user is resizing.

There are various tickets about this, most notably: #5274

This PR shows a possible workaround, with the goal of discussing this direction.

Before:

After:

[ocornut]

Hello,

I agree that ideally we would provide a demo of this, but I have an issue with the restructuring using a main loop function.

A few months ago for the purpose of unifying Emscripten building I committed 96ab68e with did a similar thing, and then quickly realized it created a big hurdle to use the example app as quick test-beds (for pretty much anything), ended up reverting with f43c6ea and found a better solution for Emscripten (better solution ea39841).

The change also seemingly defeat the purpose of 031e152 (#6374) and we would need to verify if e.g. the additional swap helps drivers frees their buffer.

I'm not sure there is a solution other than better documenting this possibility: maybe add comments in WM handler?

[learn-more]

Hello,

I agree that ideally we would provide a demo of this, but I have an issue with the restructuring using a main loop function.

A few months ago for the purpose of unifying Emscripten building I committed 96ab68e with did a similar thing, and then quickly realized it created a big hurdle to use the example app as quick test-beds (for pretty much anything), ended up reverting with f43c6ea and found a better solution for Emscripten (better solution ea39841).

The change also seemingly defeat the purpose of 031e152 (#6374) and we would need to verify if e.g. the additional swap helps drivers frees their buffer.

I'm not sure there is a solution other than better documenting this possibility: maybe add comments in WM handler?

Thanks for your detailed feedback!
I'll take another stab at this with your comments in mind.
Are you ok with keeping this open until then, or would you prefer to close this and I'll open a new PR with another solution?

[ocornut]

Best to keep this open and centralized, it's fine.