Add a config compat option for NFC distance scaling

Currently there's no way for an application to specify the "real world" scale
for in-game units. If the game doesn't use one unit to represent what should be
perceived as one meter to the user, the NFC filter's effect will be too near or
too far sounding. This allows adjusting the unit scale as applied to the NFC
filters only, correcting the misalignment.

This also removes the influence of EFX's MetersPerUnit from the NFC filters,
since many games don't use it, and those that do won't know it also influences
the perceived wave curvature along with the air absorption strength.

1 files changed, 8 insertions, 0 deletions

diff --git a/alsoftrc.sample b/alsoftrc.sample
index 4ea548ce..2dd593a7 100644
--- a/alsoftrc.sample
+++ b/alsoftrc.sample
@@ -602,6 +602,14 @@
 ##
 [game_compat]
 
+## nfc-scale: (global)
+#  A meters-per-unit distance scale applied to NFC filters. If a game doesn't
+#  use real-world meters for in-game units, the filters may create a too-near
+#  or too-distant effect. For instance, if the game uses 1 foot per unit, a
+#  value of 0.3048 will correctly adjust the filters. Or if the game uses 1
+#  kilometer per unit, a value of 1000 will correctly adjust the filters.
+#nfc-scale = 1
+
 ## reverse-x: (global)
 #  Reverses the local X (left-right) position of 3D sound sources.
 #reverse-x = false