Interface HaloOptions

the cycle's timing, fps/loop/startTime

How the halo is composited. Additive by default, which is what a glow wants and what Wesnoth's [halo] blend_mode=add asks for; 'normal' is there for a halo that is only an overlay.

The list stops at what a halo is for rather than at every mode the renderer has: a caller who wants another one sets the inherited blendMode property directly.

the halo's frames, as Animation takes them: textures, or { texture, duration, offsetX, offsetY }

where the halo sits relative to its target, in pixels: Wesnoth's [halo] x/y