lighten
Produces a lighter variant of this color by blending with lightColor and then increasing the HSL lightness by percentage.
Used internally by the renderer to simulate directional lighting on faces.
Return
A new IsoColor with the adjusted lightness, preserving the original alpha.
Parameters
percentage
Amount to add to the lightness component (0–1 range, clamped to a maximum lightness of 1.0).
lightColor
The color to blend with before adjusting lightness.