Ground
class Ground(kind: GroundKind, var dim: Float = 1.0f, val parallax: Float = 0.4f, camera: Camera2D? = null, seed: Float = 1.0f)
A live field that fills the canvas under a drawing.
One shader drawn straight on the canvas, so in a window it runs on the graphics card. It keeps moving in silence, follows camera at parallax, and fades over fadeSeconds when kind changes.