Now use a list of preset batches with a function to add new ones to this
list.
This removes the need of new functions all over the place to reset/exit.
Introduce a UI batch cache. For the moment it's only used by widgetbase so
leaving it interface_widgets.c. If it grows, it can have its own file.
Like all preset batches (batches used by UI context), vaos must be refreshed
each time a new window context is binded.
This still does 3 GWN_batch_draw in the worst cases but at least it does
not use the IMM api.
I will continue and batch the 3 calls together since we are really CPU
bound, so shader complexity does not really matters.
I cannot spot any difference on all the widgets I could test. I did not use
any unit tests so I cannot tell if there is really any defects.
This is not a complete rewrite but it adresses the top bottleneck found
after a profilling session.
This separate context allows two things:
- It allows viewports in multi-windows configuration.
- F12 render can use this context in a separate thread and do a non-blocking render.
The downside is that the context cannot be used while rendering so a request to refresh a viewport will lock the UI. This is something that will be adressed in the future.
Under the hood what does that mean:
- Not adding more mess with VAOs management in gawain.
- Doing depth only draw for operators / selection needs to be done in an offscreen buffer.
- The 3D cursor "autodis" operator is still reading the backbuffer so we need to copy the result to it.
- All FBOs needed by the drawmanager must to be created/destroyed with its context active.
- We cannot use batches created for UI in the DRW context and vice-versa. There is a clear separation of resources that enables the use of safe multi-threading.
