Revamp / simplify monster melee poison application

This removes AF_POISON_MEDIUM, leaving only AF_POISON and
AF_POISON_STRONG as the normal poison attack flavours, but basing
poison damage inflicted by attacker HD instead (AF_POISON_STRONG
inflicts more per HD, but importantly partially ignores rPois as
it presently does). Also it simplifies some of the random checks
for whether poison is inflicted at all.

In effect, this means that high HD monsters should inflict amounts
of poison that are more tactically relevant than present (which
seem generally desirable to me) while simplifying how they do so,
and keeping the poison damage from early creatures lower (as they
also have low HD).

Many creatures seem to fit a natural progression with this new
system, but there are several cases where monsters of the same HD
were explicitly differentiated by poison severity (such as scorpions,
with the same HD as adders but worse poison, or wolf spiders, with
more HD than any other spider but explicitly weaker poison). Some
of these will likely need individual changes.

1 files changed, 3 insertions, 3 deletions

diff --git a/crawl-ref/source/ghost.cc b/crawl-ref/source/ghost.cc
index c38d89d3bf..52ab7e7335 100644
--- a/crawl-ref/source/ghost.cc
+++ b/crawl-ref/source/ghost.cc
@@ -504,7 +504,7 @@ static attack_flavour _very_ugly_thing_flavour_upgrade(attack_flavour u_att_flav
         u_att_flav = AF_NAPALM;
         break;
 
-    case AF_POISON_MEDIUM:
+    case AF_POISON:
         u_att_flav = AF_POISON_STRONG;
         break;
 
@@ -534,7 +534,7 @@ static attack_flavour _ugly_thing_colour_to_flavour(colour_t u_colour)
         break;
 
     case GREEN:
-        u_att_flav = AF_POISON_MEDIUM;
+        u_att_flav = AF_POISON;
         break;
 
     case CYAN:
@@ -648,7 +648,7 @@ static resists_t _ugly_thing_resists(bool very_ugly, attack_flavour u_att_flav)
     case AF_ACID:
         return MR_RES_ACID;
 
-    case AF_POISON_MEDIUM:
+    case AF_POISON:
     case AF_POISON_STRONG:
         return MR_RES_POISON * (very_ugly ? 2 : 1);