I'm not sure I understand what you mean here...do you want bleeding damage to remove stoneskin layers? If yes, I cannot agree, actually it probably shouldn't even work on a stoneskinned character. If not, the current solution works exactly as it always did, bypassing stoneskin completely.
Also, bleeding as opcode #17 goes straight through stoneskin, ofc if it were physical damage it would remove stoneskins on a per-round basis, but the gnasher club already does that and it is not a bad way to simulate a "wounding" effect. Perhaps #174 could be used to overide the hard-coded slashing damage sound.
In the vanilla game bleeding and poison both share opcode #25, stoneskin protects against this effect as well as the poisoned portrait icon (an interesting concession to realism by the developers, for injected poison anyway). However, it's obviously undesirable for every creature immune to poison to be immune to bleeding, or for bleeding to be curable via antidote.
Poison actually interacts strangely with mirror-image effect as well: Mirror-images can block both poison and the poisoned portrait icon (again, realistic if it's not AoE poison), but if you manage to cast MI while poisoned the damage tick will remove mirror-images even though the damage itself is not prevented by MI.
Delayed damage of any sort called through opcode #12 (like melf acid arrow) will also remove the mirror-images. This is kind of annoying, either it hit your character and MI should not protect against it in successive rounds, or it hit an image and you character shouldn't incur further damage...
Overall, I think delayed physical damage is the least buggy way to implement bleeding; it will still behave strangely with mirror-images, but at least it won't go straight through stoneskin (as in vanilla). It will remove stoneskins, but this is possibly justifiable, as whatever "wounding" factor which makes the sword work can also eat away at stoneskin.
Also, a mirror-image should realistically be removed by every attempted attack since any contact would reveal that it's an illusion - if they wear off faster than normal due to a hit from a wounding weapon it's not such a big deal, this should happen anyway in the course of combat.
Edited by polytope, 05 February 2012 - 02:14 AM.