Now, I figured that the handling for would be buried somewhere deep in the rendering code beyond the reach of my addon fu, but some source diving suggested that the Map:addEffect() method was a potential inroad. See, unless a talent specifies otherwise, any effect it leaves behind is displayed at the very highest "z-depth", on top of everything else. A few effects like Mucus manually specify a z-depth of 6 to put it under the player (never could find what z-depth actors are drawn on, but since map z-depth ranges from 0 to 19, I'm guessing 10). So I figured if I could sneak in ahead of the engine and insert a z-depth of, say, 7 for effects that don't specify their own, that should put all effects below actors.
The result is my new Effects Under Actors addon. I can't confirm that I've found every place a z-depth needs to be set for it not to default to the top layer, but I've tested it on wildfire archmages' Burning Wake and it appears to do what it's supposed to do, as depicted in the following screengrab I set up for the Steam page image:
- blastwave-test.jpg (172.45 KiB) Viewed 6907 times
[Thinking ahead, this addon might or might not be suitable for inclusion in ZOmnibus or Zomnibus Lite, but it would probably need a game option to turn it on/off if we did.]
[Technical notes:]
Code: Select all
Superload:
mod.class.MapEffects:
Map:addEffect() [to change the z-depth of effect particles]
Maybe a further useful addition to it will be an option to display just one layer of effects when there are multiple ones overlapping on a certain tile? Don't know how hard that would be, but the said wretchlings can wreck havoc on older systems when you meet a pack or three. 
My reference-counting hackery to "flatten" particles for grid-based effects like Corrosive Vapor was, it turns out, also being applied to stuff like the "icestorm" effect particle for Winter's Fury when it shouldn't — not least because if you move while the effect is active, the reference counting gets messed up and the particle never gets removed.