renderer: ensure makecurrent isnt called twice

[gulafaran]

depending on the attachment and commitstate we might end up calling makecurrent twice on an already current context, and on destruction we also make it current yet again even tho it was current. drivers doesnt keep track of this and is very inefficient when calling this on itself all the time. add a bool and only call it when it has changed or require change.

also remove unusued EGLSurface draw, read.

[vaxerski]

what if hyprland switches context?

[PlasmaPower]

The rest of this change makes sense but I think we need to restore the saved EGL state in case we're switching from a different context from a higher level call (e.g. mGPU CPU blit I think).

[gulafaran]

Only way the context wouldnt be current is if it got changed in the first place, and since its not threaded it wont be any different from the constructor. im even considering looking into moving most of these calls and ensuring the context switching is minimal, the flamegraph on just a 10 second rendering with a dgpu external monitor 30% is spent in nvidia with eglmakecurrent

[PlasmaPower]

CDRMRenderer::blit initializes an EGL context but then might call primaryRenderer->readBuffer which initializes its own separate EGL context. Once readBuffer returns the EGL context should be reset to the blit's context.

[gulafaran]

well yeah, but currently CEglContextGuard works on constructor/destructor. there is no way it ends up wrong as i can see it. besides ending up calling makecurrent on already current context that is

blit {
 CEglContextGuard()
 
dostuff()
bleh->readBuffer() {
      CEglContextGuard()
      dostuff()
      ~CEglContextGuard()
  }
  
  ~CEglContextGuard()
}

[PlasmaPower]

I think it'll work with the current code, but if dostuff registered a draw or read surface which was used by blit after readBuffer, the current code would restore that when readBuffer returns and its context guard is destructed, but the new code erases the draw and read surfaces.

[gulafaran]

only place the draw or read changes is from using eglMakeCurrent , both hypr and aq uses EGL_NO_SURFACE on all those calls.

[gulafaran]

what if hyprland switches context?

as below thread, AQ never calls hypr* directly. CEglContextGuard is a "scope" guard constructor/destructor. so with these changes it only changes when needed, and restores if it changed. before it changed no matter, and restored no matter the current context. and incase of blit/readBuffer that "nests" it. previously it would call go from

example

blit {
CEglContextGuard() // make intel current(even if current).

readbuffer {
  CEglContextGuard() // make nvidia current even if current
  foo();
  ~CEglContextGuard() // restore intel or nvidia even if it was current already
}

~CEglContextGuard() // restore blit scope, meaning yet again make intel current.
}

so the destructors alone atleast calls it twice on same context in that code path.