Feature Request - Devil's Sight should see through Magical Darkness

[Backnard]

Perfect-Vision's implementation of Magical Darkness is the most accurate I've seen in a VTT with one exception: Devil's Sight should ignore it, A token with Devil's sight should be able to see through the area of darkness from the outside and should be able to see out when inside. Please consider adding this if possible, Warlocks with Devil's Sight who cast the Darkness spell are an unfortunately very common occurrence and your module is the closest I've seen to making that doable in Foundry.

[dev7355608]

Devil's Sight and Blind Sight is coming in version 3.6.0.

[Backnard]

Oh, Awesome! Well then, thanks for making vision in Foundry more and more perfect. Your module is living up to its name quite nicely and is one of my favorites!

[dineshm72]

Agreed. I have a devil's sight warlock and a blindfighting fighter who can't wait for the 3.6 version! Great job!

[dev7355608]

Well, I lied about devil's sight & blindsight being part of the 3.6.0 release, but it's coming, don't worry.

[dineshm72]

Just adding some encouragement on this... my devil's sight warlock has now started casting darkness on himself and then attacking from within it, and at the moment I end up just having to delete the very nice perfect vision darkness in order to fake it so that he can still see.

[dev7355608]

I planned to redesign the vision rules UI entirely in order to integrate devil's sight / blind sight nicely, but it was announced that Foundry v10 is going to feature Vision Modes, which will replace all/some of PV's vision rules; I'm not quite sure what this is going to be, so I'm not going to do a complete redesign of the vision rules UI now.

Also allowing the distinction between natural obstructions like fog and magical darkness is tricky. I need to build it as system agnostic as possible: usually there are multiple levels of magical darkness (lesser / greater darkvision). I don't want to create a big mess in the UI. I might just add a simple minimum sight limit for now without different kinds of sight limits and postpone the distinction between fog and magical darkness (blindsight and magical darkvision) etc to a later update (when v10 is released probably).

[dev7355608]

The V10 release of PV is going to feature Vision Limitation. It is the replacement for Sight Limit, and it is going to allow you to configure different limits for vision and each Detection Mode. If Devil's Sight/Blind Sight/True Sight are defined by the system, you are able to make exceptions for it.

[dineshm72]

Has anyone found a module which has added Devil's Sight, True Sight, or (if needed) Blind Sight as options in the dnd5e system? Until that happens, we can't use the above sweet new feature, right?

[dev7355608]

Has anyone found a module which has added Devil's Sight, True Sight, or (if needed) Blind Sight as options in the dnd5e system? Until that happens, we can't use the above sweet new feature, right?

@dmaneyapanda Adequate Vision

[dineshm72]

Awesome!

At the risk of taking this issue over, I'm having some trouble getting the new settings shown above to work, maybe you can point out what I'm doing wrong.

In this scene I have set up a token with Devil's Sight detection, put in a Darkness spell (and modified it to limit vision to 0 and limit devils sight to 60). Here it is with no token's selected:

Since I'm the GM, I can see the light on the other side of the darkness spell. When I select the token with Devil's Sight, I'm expecting that token will also be able to "see through" the darkness spell, but it looks like the spell is still blocking sight into/through it.

Am I missing something?

[dev7355608]

That's basically a limitation of detection modes: they can only detect/see tokens. Only Vision Range (Basic Sight) allows the token to see the environment. Basic Sight is darkvision + normal light-based perception, but it could also be used represent other senses. I hope Foundry gets rid of Basic Sight in the future and lets you select, for example, Devil's Sight instead of Darkvision as the primary sense or something like that. It's hard to know for PV what Basic Sight is supposed to be without system/module-specific compatibility code.

So normal vision is be blocked, but the token is able to see other tokens behind the magical darkness with Devil's Sight. Unless you run different rules for magical darkness/Devil's Sight, the limit of Devil's Sight should be infinity (unrestricted), otherwise the token can only see up to 60 feet in magical darkness.

[dineshm72]

Ahh OK I think I'm coming to better understand the difference between the Vision mode and the Detection mode(s), thanks. Also appreciate the nudge on 60 vs infinity - I was trying to get it to work and wasn't sure whether 0 or infinity was the right setting, so I picked something in the middle that should have worked at some distance in my example.

I'm a little confused about "lets you select, for example, Devil's Sight instead of Darkvision as the primary sense", because I think that is possible now, isn't it?

In fact, if you select Tremorsense, things seems to mostly work the way I was expecting them to for Devil's Sight (which, if selected, actually doesn't work), just in a tremorsensy way rather than a devils sighty way:

Aside: I would expect tremorsense would work through walls too, but I suspect that is something that would have to be taken up with the Adequate Vision mod.

Is this perhaps a path forward? I don't understand at all whats going on under the hood with Adequate Vision to know, but it seems like if it can make tremorsense work, then there should be a way to make Devil's Sight work. But maybe that also all needs to be done on the side of that mod, not yours.

[dev7355608]

For the most part vision modes control how the token perceive, not what; but a vision mode can turn off lights, like Tremorsense, which has an affect detection modes. The Tremorsense vision mode isn't actually Tremorsense (the detection mode), it's really darkvision with the lights turned off. That's why it doesn't go through walls and is affected by the blinded condition. It's still just basic sight.

It's doesn't really make sense to apply limitation based on the vision mode, because visibility should be purely the job of detection modes. Even if PV tried to, there are the following problems, which are basically impossible to solve without module/system-specif compatibility code.

• For example, Monochromatic could be used for a color-blind creature with darkvision, but also for a color-blind creature with devil's sight.
• A lot of detection modes don't have corresponding vision mode. For example, Adequate Vision re-uses the Devil's Sight vision mode for Truesight, because there wouldn't be any difference between the two under the hood, which would mean that PV would apply devil's sight restrictions to truesight.
• There could be vision modes that are used for the combination of two senses.
• There could be stylistic variants (different shaders) of the same vision mode that would correspond to the same sense.

Tremorsense can see through the magical darkness, because the vision mode turns off lights and so the vision limitation of the light source is disabled too. I should probably change that: just because a token cannot see light, doesn't mean that the vision limitation of a light source can be ignored.

[dineshm72]

OK, I think I'm getting it. Let me try to restate things to see if I have it right.

• The Visions/Detection mode architecture now implemented in foundry is perhaps itself somewhat fundamentally flawed. Vision mode should be just how you perceive (i.e. normally, dark vision coloration, true sight, full mono, tremor/lightless/whatever this should be), and Detection modes should implement the details of what you can see (both environment and tokens) in that way (restricted by walls or not, distance limitation, see invisible, etc.).
• Instead, some of the "what you can see" is baked into Vision modes now, and detection modes only have the ability to highlight tokens, not actually show the environment
• Moreover, the vision modes aren't even that flexible now, they only allow you to define a small number of variations on basic sight (e.g. they are always restricted by walls which restrict vision). So there is no way to implement a real tremorsense vision (aside: I'm not sure what that would be, maybe tremorsense shouldn't actually see environment and walls anyway, but now you couldn't do it even if you wanted to), or do a real devil's sight vision mode that ignores magical darkness and lets you see the environment into and through a darkness light source. You can set them to turn off/ignore all lights, but that's it.

So to sum up, the dream of being able to implement a real Devil's Sight is not yet here, and will require some fundamental changes to the vision/detection architecture. For now, the vision part (i.e. environment) will still be pretty basic, and all you can effectively implement is token detection into and through magical darkness. If that's not good enough, then I suppose one could fall back on just manually turning the darkness light on and off, much like I've been doing up until now for my warlock.

I vaguely remember during the unveiling of the detection modes they talked about how early on they wanted things different, but couldn't figure out how to effectively show multiple vision modes operating at once (e.g. a player with darkvision who casts a spell to get tremorsense), so they had to simplify things. Perhaps that is related to why they ended up where they did.

[dev7355608]

[...] You can set them to turn off/ignore all lights, but that's it.

Yes. But the FOV/LOS polygon (wall interaction etc) should be the job of detection modes. The vision mode should ideally just determine how the vision is rendered.

PV cannot offer vision limitation for senses that don't have their own detection mode in a system/module-agnostic manner. It would be possible to add compatibility code into PV for Adequate Vision for proper Devil's Sight. But dnd5e isn't the only system with magical darkvision; so naturally I'd have to implement it for other systems too. That's a lot to maintain. I don't want to have that kind mess in PV. API improvements would have to start with the elimination of Basic Sight in my opinion: the split of the Basic Sight into darkvision and standard light-based perception.