[WSOD fix] Merge https://github.com/RetroPie/EmulationStation/pull/88

[rtissera]

Please make sure your PR is ready to be merged !

• You added the changes in CHANGELOG.md
• You choose the right repository branch to make the PR
• You described the PR as below

Fixes "white screen of death" by rewriting major parts of Texture and VRAM management.

This is just a port / clean merge of RetroPie#88 so all credits go to @fieldofcows for the hard work.

Changes :

• Add Max VRAM setting to command line
• Save/Load Max VRAM setting, expose it to the "UI settings" menu
• Rewrite most of texture data handling to swap out textures when reaching VRAM capping limit.

Related to (put here the others PR in other repositories)

[gillg]

Good job ! I trided to merge it few days ago, but I had too much issues... :)

[rtissera]

Changelog updated, can we discuss merging ?

[rockaddicted]

@rtissera Ok so I was very busy, but I finally tested your PR. Did you test it form your side ?
So, if I'm using a light theme or activates only few systems to stay below the vram size limit, I have no problem. Everything work well.
But when I exceed the size limit, if I scroll "too fast" the system list, a white screen is displayed before to display the real background image.

Here is a video to illustrate this issue : https://youtu.be/lwur-yMzmJ0

Didn't test it on a "stock" emulationstation, only on an ES based on our fork.
@fieldofcows Does it have the same issue with a stock/retropie ES ?

[fieldofcows]

That behaviour is by design.

The problem being addressed is that the entire theme does not fit into vram. Hence some sort of 'swapping' of images needs to be performed. What you're seeing is an on-demand based loading of the images. This obviously does not happen instantly so the image is only displayed once memory has been freed, the new image has been streamed in and a texture generated.

I guess it can be improved by better prediction of what images are about to be displayed but ultimately, fast scrolling many MB of images is going to result in visible load artefacts.

[rtissera]

@rockaddicted Any update on this ?