Unify framebuffer location

[cnlohr]

This is a long-term concern. Nothing needed immediately.

It is a not-insignificant perf hit to call getPxTftFramebuffer or to reach into and get a global pixel register value. However, using file-static variables are fast.

It would be really good if we could avoid the function call, or global read.

I was seeing ~10% perf boosts on the flight sim by making these changes.

[AEFeinstein]

The framebuffer is malloc'd rather than being file static. I think if you want to static it, we'll also need to steal some memory from the heap in the linker.

if (NULL == pixels)
{
    pixels = (paletteColor_t*)malloc(sizeof(paletteColor_t) * TFT_HEIGHT * TFT_WIDTH);
}

[cnlohr]

No need to static it or not - its getting access to the pointer that's the hard/slow part. Making a project-global variable takes an inordinate amount of time to load at the beginning of the function.

[AEFeinstein]

OK. If it's really that easy and impacts flightsim, do it in that branch?

[cnlohr]

Good to have a discussion on - I am doing it where it counts most for flightsim, but could improve wsg timing as well.

[AEFeinstein]

Is there any downside?

[AEFeinstein]

Closing until we need the perf boost.