GdxSetup: Update generated main class to look more modern

[Hyperion2400]

The project that is generated by GdxSetup looks quite dated with its bright red background and the pixelated Bad Logic Games logo.

I updated it to make it look more modern.

Before:

After:

[Frosty-J]

Could define position on one line as float imgPosX, imgPosY, though I'm not saying you should. Since then we get into the weeds of "oh but what about access modifiers" and all that. Speaking of which...

If we're doing this, as much as I love how iconic the eye-bleeding red is, I'm really tempted to ScreenViewport it up to stay centred rather than stretch on resize. Even wrapping it as an Image and tossing it in a Stage if we're feeling rambunctious, in which case an action can be applied to give it some movement.

If MyGdxGame extends Game, the code can go in a ScreenAdapter, giving the dispose method a purpose (since you conceivably might want to dispose a screen; never found reason to dispose at the application level since resources will be freed by the OS). You can see why I've never made a pull request for that myself - the scope just keeps increasing.

[Hyperion2400]

I was thinking about doing something similiar as Phaser which has the logo bouncing around with a particle effect.

You can paste the sample code into an html and open it with your browser to see for youself: https://phaser.io/tutorials/getting-started-phaser3/part5

But that would require a bit more code so I opted for the simpler solution that is still a big improvement imo. Also I can't test on all platforms so I didn't want to deviate from the working code too much.

As for the code I first used a vector for the position but then the initialization would be spread over 2 lines and I wanted the sample code to look as simple and tidy as possible.

[Frosty-J]

Vector2 is safe to construct before create(). If using one, could do imgPos.x = ... instead of setting both floats at once if it's cleaner.

[Hyperion2400]

Sounds good. I changed it.

[Frosty-J]

Can alternatively use a Sprite if storing position separately is too messy. This is not a suggestion, just a thought - I don't know how much you've libGDX'd before.

// create
img = new Sprite(new Texture("logo_dark.png"));
img.setCenterX(Gdx.graphics.getWidth() / 2f);
img.setCenterY(Gdx.graphics.getHeight() / 2f);

// render
img.draw(batch);

// dispose (seems pointless)
img.getTexture().dispose();

Underscores in filenames can be a bit sketchy if they're ever run through Texture Packer, so often dashes are used instead. E.g. bob_version_2 would by default become region bob_version with index 2. I may or may not have been bitten by that the other day. This image is unaffected since dark is not a number. Though I realise this is the filename used for the website.

I should leave this place now, as I could go on indefinitely. It's such a difficult thing, knowing what's ideal to have in the main class. Something that says "it is working; welcome to libGDX."