Remove custom WebGL code from this sim

[jessegreenberg]

#42 is an investigation about whether we can safely remove WebGL from ESP and keep good performance on PhET's targeted platforms. Should we see a 👍 there (which is likely), these are the immediate things that should be done (with recommendations from @samreid over slack):

• Delete CircularOutlineWebGLNode
• Delete PieChartWebGLNode (edited)
• Remove renderer args from SkaterNode BarGraphForeground and others.
• Remove custom GaugeNeedleNode solution for gauge animation in the WebGL layer
• Redo some of the layering code?
  • Revisit Bars in bar graph appear in front of track energy-skate-park-basics#425, Bar chart goes behind skater but in front of track energy-skate-park-basics#295
  • Remove layering functions addToBottomLayer addToTopLayer.
  • Remove bottomLayer, webGLLayer, and topLayer nodes.
• Combine BarGraphForeground and BarGraphBackground into a single node? (edited)
• Use griddle for the bar graph, see Use griddle for the bar graph? #31
• Remove GaugeNeedleNode custom webgl code in ESP Remove GaugeNeedleNode

[jessegreenberg]

SHA and date before removing WebGL:

commit 48a5a521bdbdcdbcd418bc244cfca708606b77d0 (HEAD -> master, origin/master, origin/HEAD)
Author: Jesse <[email protected]>
Date:   Wed Apr 17 14:28:34 2019 -0400

    use SunConstants.VALUE_NAME_PLACEHOLDER for #63

[jessegreenberg]

Combine BarGraphForeground and BarGraphBackground into a single node? (edited)

Lets not do this until we try to use griddle first.

[jessegreenberg]

Bar graph is done, see #31. Ill work on the pie chart next.

[jessegreenberg]

They can just be removed at this point.

[jessegreenberg]

Remove bottomLayer, webGLLayer, and topLayer nodes.

We still want some layering so that subtypes of EnergySkateParkSCreenView can layer things in front of and beind the skater. I will keep bottomLayer (for control panel UI components) and topLayer (for interactive components that are draggable on top of the rest of the UI).

[jessegreenberg]

One remaining comment related to WebGL says:

    // Use a separate texture for left/right skaters to avoid WebGL performance issues when switching textures
    var leftSkaterImageNode = new Image( skaterLeftImage, {
      cursor: 'pointer',
      tandem: tandem.createTandem( 'leftSkaterImageNode' )
    } );
    var rightSkaterImageNode = new Image( skaterRightImage, {
      cursor: 'pointer',
      tandem: tandem.createTandem( 'rightSkaterImageNode' )
    } );

@samreid would you recommend leaving this as is or should we try to do this with a single Image Node? Commit that added this was fcbe3ed, but I couldn't find an issue, do you remember what platform/context had an issue with this?

[jessegreenberg]

Otherwise, I think all custom rendering has now been removed.

[samreid]

We have to use 2 images for the skater, it contains text and cannot be flipped programmatically or "PhET" would come out backwards. I recommend recommenting that part and leaving the code as it is. Thanks!

[jessegreenberg]

Oh yes I see! Thanks!

[jessegreenberg]

Then this issue can be closed!