Defrag the sprite batcher before every flush

[bullno1]

This ensures that the atlas is defragged before every flush.
Both RAM and VRAM usage are reduced significantly.
No change to the cycling flag is needed.

However, I have no idea how this affects performance since there is another per-frame defrag.

[bullno1]

This seems to work but I think it should be a dirty flag instead?

Like:

• If there is a new sprite, mark the batcher as dirty.
• If there is a flush, defrag if dirty and clear the dirty flag.
• Per frame, defrag on tick if not already.

[pusewicz]

This branch brings my memory usage in the demo to normal values (650MB) which I think is fine (it always seems to be more on macOS). The CPU is on ~100% though.

[bullno1]

If you turn on vsync (cf_app_set_vsync(true)), does CPU usage drop?

Also, I suspect that calling defrag so often is suboptimal.
Will look into the dirty flag idea later.

[pusewicz]

Much better, but still it's higher at around ~30%.

Here's htop:

Here's my Activity Monitor:

But you know what, even on my branch the CPU usage is the same. Also even with vsync false I see it at ~65%. I guess depends what display I run it on.

To sum up, the CPU usage seems to be the same before and after the change.

[bullno1]

16 threads....

Yeah, it's probably your driver.

[pusewicz]

I don't think the thread count is an issue. But again, I think this change works.

[RandyGaul]

Defrag is designed to be called per frame. Internally it won’t do work until needed, and the work is almost always worth doing.

[bullno1]

So calling it before every flush is fine?

[RandyGaul]

Yes. There was an issue with imgui though, needing to defrag/flush after drawing, but there's an if-statement and dirty-flag for this already. The delay was needed to avoid invalidating texture handles for ImGui to draw CF sprites, this let CF inject it's sprites for rendering within Dear ImGui.

[bullno1]

How to approach this though? Can the handles in dearimgui be "virtualized" or indirectly looked up somehow?

Because as I understand it, if defrag is delayed before flush it leads to this problem.

Alternatively, dearimgui can be treated as "debug tool" and its rendering is delayed in the case of a flush ... somehow and its entire command queue just get discarded.

[RandyGaul]

Did you test with imgui?

[bullno1]

Only the samples but none of them render images