Simplify FlxGraphicShader

[Geokureli]

Addition to #3326

Another attempt at the other part of #3321

Simplifies FlxGraphicsShader and removes ifs for mix calls. Let's hope that's a good thing

To Dos

• See if thats a good thing
• Figure out how to profile shaders
• Learn more about shader attributes and flixel's batch rendering

[Geokureli]

gonna shelf this until I learn why hasTransform is being set to false, in renaine

[Raltyro]

Why change if statements to mix?

[Geokureli]

Why change if statements to mix?

If statements should be avoided in GPUs, wherever possible. Here's an explanation: https://stackoverflow.com/questions/37827216/do-conditional-statements-slow-down-shaders/37837060#37837060

[Raltyro]

Any plan to do this the same to openfl GraphicsShader too?

[Geokureli]

Any plan to do this the same to openfl GraphicsShader too?

None of this will happen if I don't find a good way to profile these changes. As for openfl, I dunno, the gains here are pretty small, and changing it wont impact us all that much as we already overwrite theirs in the extended class