Actor should not have its own opacity property

Context

Actor should not have its own opacity property. Currently, it’s used to facilitate the Fade Action, and to override the opacity of the Actor’s color property (if it has one). This has the potential to cause confusion, over which property is actually used (see #837).

Proposal

Actor.opacity should be deprecated in favor of using the opacity of Actor.color.a or Actor.currentDrawing.opacity (if the IDrawable has an opacity property, such as if it is a Sprite)

[djcsdy]

Just wasted a bunch of time on this. It could not possibly be more confusing. Everything about Actor.opacity is inconsistent and broken.

• Constructing an Actor with a color causes the opacity of the Actor to be set the the alpha value of the color, but subsequently updating the alpha value of the color has no effect.
• Setting the color of an existing Actor (with opacity > 0) to Color.Transparent causes the Actor to turn black and retain its previous opacity.
• Drawables attached to an actor use the opacity set on the Actor but ignore the color.
• Actor sets this.color.a = this.opacity in its update function (WHY?!) so classes that extend Actor and define their own draw function inherit the weird relationship between color and opacity. For example, Label. They could override update but then they lose the existing implementation of a bunch of other useful stuff.
• Actor sets visibility = false in update when opacity === 0, so if you ever set the opacity of an Actor to zero then it disappears and doesn’t come back when you set the opacity back to a value > 0.
• It’s just awful and I don’t much care for it at all.

[github-actions[bot]]

This issue hasn’t had any recent activity lately and is being marked as stale automatically.