Change how covering mutations (scales) work

[chequers]

Covering mutations are the following list:
MUT_DISTORTION_FIELD, MUT_ICY_BLUE_SCALES,
MUT_IRIDESCENT_SCALES, MUT_LARGE_BONE_PLATES,
MUT_MOLTEN_SCALES,
MUT_RUGGED_BROWN_SCALES, MUT_SLIMY_GREEN_SCALES,
MUT_THIN_METALLIC_SCALES, MUT_THIN_SKELETAL_STRUCTURE,
MUT_YELLOW_SCALES, MUT_STURDY_FRAME,
MUT_SANGUINE_ARMOUR,

You can only have three total levels of mutation amongst all these scales. Currently, if you quaff mutation, it rolls a covering mutation, and you already have three levels of covering, the mutation will fail.

I think covering mutations are fun, but they are often most fun at level 3 (where you get a bonus resistance from many of them). The mutation system should make it more likely that with infinite good mutations you end up with three levels in one covering mutation rather than one level in three covering mutations.

My proposal is the following:
1. If you roll a covering mutation and have zero to two levels of covering: nothing changes from now
2. If you roll a covering mutation and have three levels of covering: change the mutation rolled to a covering mutation that you already have (weighted by number of levels), then delete a random covering mutation level (not weighted by level), then add a level of the mutation you re-rolled.

Examples:

Player A has no mutations. They get a mutation which rolls yellow scales. Yellow Scales 1 is applied as normal.

Player B has Yellow Scales 3. They get a mutation which rolls sturdy frame. Nothing happens.

Player C has Yellow Scales 2 and Sturdy Frame 1. They get a mutation which rolls blue scales. The mutation is re-rolled to one of the player's existing covering mutations, a random covering mutation is removed and a level of the mutation is added.
Possible outcomes:
* 33%: Re-roll to yellow scales (66%), remove yellow scales (50%): Yellow Scales 2, Sturdy Frame 1
* 33%: Re-roll to yellow scales (66%), remove sturdy frame (50%): Yellow Scales 3
* 17%: Re-roll to sturdy frame (33%), remove sturdy frame (50%): Yellow Scales 2, Sturdy Frame 1
* 17%: Re-roll to sturdy frame (33%), remove yellow scales (50%): Yellow Scales 1, Sturdy Frame 2

[Rast]

2. If you roll a covering mutation and have three levels of covering: change the mutation rolled to a covering mutation that you already have (weighted by number of levels), then delete a different random covering mutation level (not weighted by level), then add a level of the mutation you re-rolled.

Fixed to prevent the extremely common scenario where you roll a covering mutation but the end result is no change.

[duvessa]

I think covering mutations are fun, but they are often most fun at level 3 (where you get a bonus resistance from many of them).

Can't speak for others, but I would currently rather have 1 level of 3 different scales (usually 6 AC) than 3 levels of 1 scale (usually 4 AC and a useless resistance).

Perhaps the concept of covering mutations should go away and most of the existing covering mutations should be made draconian/demonspawn-exclusive. There's no meaningful difference between molten, icy, yellow, and green scales, and literally no difference at all until level 3. Brown scales are a second, weaker version of robust, we don't need two versions of robust as random mutations. And fur is another random mutation that gives you AC!
I'd say remove the covering distinction, and continue letting players mutate sturdy frame randomly since it's the one that might actually change your character a bit. Demonspawn occasionally getting both scales and sturdy frame doesn't seem like a problem to me.

[chequers]

2. If you roll a covering mutation and have three levels of covering: change the mutation rolled to a covering mutation that you already have (weighted by number of levels), then delete a different random covering mutation level (not weighted by level), then add a level of the mutation you re-rolled.

Fixed to prevent the extremely common scenario where you roll a covering mutation but the end result is no change.

Well, the point is that sometimes there would be no change. The system is biased towards increasing your most common covering mutation (33% increase, 50% stay the same, 17% decrease)

[Reptisaurus]

I think covering mutations are fun, but they are often most fun at level 3 (where you get a bonus resistance from many of them).

Can't speak for others, but I would currently rather have 1 level of 3 different scales (usually 6 AC) than 3 levels of 1 scale (usually 4 AC and a useless resistance).

Perhaps the concept of covering mutations should go away and most of the existing covering mutations should be made draconian/demonspawn-exclusive. There's no meaningful difference between molten, icy, yellow, and green scales, and literally no difference at all until level 3. Brown scales are a second, weaker version of robust, we don't need two versions of robust as random mutations. And fur is another random mutation that gives you AC!
I'd say remove the covering distinction, and continue letting players mutate sturdy frame randomly since it's the one that might actually change your character a bit. Demonspawn occasionally getting both scales and sturdy frame doesn't seem like a problem to me.

Feels like a bit of a Xom nerf. Xom usually eventually (like, by level 16 or so) gives you good mutations, and scales was one of the stronger mutations.

[prozacelf]

Xom also usually gives you 2-3 different types of scales, a couple of natural resistances otherwise, and a random grab-bag of 6-12 good mutations otherwise with maybe one or two bad ones mixed in by the end of a game.

I don't think that changing how scales/"covering" mutations work currently would in any sense be a nerf to Xom. Particularly given that one of the defining characteristics of Xom is that s/he is probably going to get you killed before you get your second rune anyway.