Electron 2.0.6 causes flickering on Native export (#566)

[Wend1go]

Describe the bug

The recently submitted patch for solving the flickering on Android and Ubuntu Touch causes flickering in the Electron export (tested on Windows and Linux). #566

To Reproduce

1. Export a game for native platform
2. Run the game
3. The background colour flickers through the game occasionally (although not in fullscreen mode)

Other details

I think I need to set the new "transparent=true" parameter to only apply to mobile exports and keep the "transparency=false" for the Electron export.

@4ian is it ok If add a condition like this to runtimegame-pixi-renderer.js?

 * Create a standard canvas inside canvasArea.
 *
 */
gdjs.RuntimeGamePixiRenderer.prototype.createStandardCanvas = function(canvasArea) {
    this._canvasArea = canvasArea;

    //Create the renderer and setup the rendering area
    if (navigator.isCocoonJS){
        //This prevents flickering on some mobile devices
        PIXI.glCore.VertexArrayObject.FORCE_NATIVE = true;
        //"transparent: true" is needed to avoid flickering issues on some mobile phones (see #566)
        this._pixiRenderer = PIXI.autoDetectRenderer(this._game.getDefaultWidth(), this._game.getDefaultHeight(), {transparent: true} );
    } else{
        this._pixiRenderer = PIXI.autoDetectRenderer(this._game.getDefaultWidth(), this._game.getDefaultHeight());
    }

[4ian]

The hard thing is to come up with a solution that allow to properly check if we're on mobile or not. There is gdjs.evtTools.systemInfo.isMobile(in systeminfotools.js). In this case, the body of the function should be refactored directly into gdjs.

The thing is that these checks are notoriously hard to maintain in the long term and not always very reliable.
Do we know why the flickering is happening? Can we do something else to prevent it?

[Wend1go]

I don't know either. The issue I linked in the last PR just gave a solution that worked for others but no explanation.
Since this issues are very device specific, maybe we could add the option as an action in a sub menu of the display category and leave it to the game developers to set or not set the transparency. So game devs could add a settings menu to their games and let the player decide to enable it or not depending on if the game runs smoothly on their device.

[Wend1go]

Yesterday I managed to build an Electron App locally on my system but eventhough I removed the changes made in runtimegame-pixi-renderer.js the screen was still flickering on my Linux machine.
Can someone confirm that the flickering in the Native export also occures on their systems?

[Wend1go]

I did a little more research and it seems that Electron itself is the culprit.
Electron 2.0.6 which gets chosen by electron-builder by default creates the flickering.
I tried using Electron 2.0.2 as a test and the flickering went away.

@4ian :
Could it be that you also recently updated the Electron version in the build service?

[4ian]

I did a little more research and it seems that Electron itself is the culprit.
Electron 2.0.6 which gets chosen by electron-builder by default creates the flickering.
I tried using Electron 2.0.2 as a test and the flickering went away.

Good catch!

Could it be that you also recently updated the Electron version in the build service?

No but the latest version being used and Electron 2.0.6 being released a few days ago, the build service is now using it.
Let me check if I can pin it to a specific version - will help for future similar issues.

Also I want at some point to update Electron that is used for the IDE (https://trello.com/c/fIyghcLM/87-update-electron-to-latest-version), let's try to find something that has not this issue.
Can you find any online issue/report about this problem btw?

[4ian]

Should be fixed by 9a55167
Note that this was entirely fixed by updating the files that are generated by GDJS when exporting the game :) (good example that the build service is useful, but you still have full control on your game)

[ghost]

It also flickers on desktop, using the latest electron version 2.0.6.

[4ian]

@rikazukun Yes, see the previous messages ;)

[Wend1go]

I don't think we need to go back that far, 2.0.5 was working without issues. (I just tested it again)

I couldn't find a bug report about the flickering over at electron but the changelog for 2.0.6 states this:

Fix flicker on Macs when the GPU is under heavy load. #13896

I don't really understand what they did in that PR, but they changed something OpenGL related.

[Wend1go]

Reported bug on Electron Repo:

[Bug][2.0.6] Flickering with PixiJS #13983

[Wend1go]

Electron 2.0.7 seems to have fixed it.

[4ian]

Awesome. Thanks for reporting the issue on electron and glad that they already had the fix :)
I'll update to use version 2.0.7 for exported games in the next version of GDevelop. At least having a pinned version will avoid such problems later.
For the current version, I guess the workers will pick 2.0.7 once it's officially released.

[Wend1go]

Sounds good, closing this now.

[4ian]

Might be a good idea to bump GD to use Electron 2.0.7 too btw.