Flesh out README.md

Author: different55

README.md

@@ -1,3 +1,49 @@
 # Closed Captions
 
-Adds closed captions for sound effects.
+Add closed captions/subtitles to Vintage Story. Make the game playable on mute!
+
+Based heavily on goxmeor's existing subtitles mod, but now updated for v1.21, and refined visually somewhat, sorta.
+
+## Features
+
+### Directionality
+
+For sounds within a normal field of view, there will be no arrows or other indicators.
+
+For sounds at the edge of your field of view, a single directional arrow is drawn.
+
+For sounds to your sides, double arrows are shown.
+
+And for sounds behind you, two dots are shown on either side of the sound description.
+
+### Colorfulness
+
+Sounds are also color coded. "Dangerous" sounds that might alert you to a dangerous situation are highlighted in orange. A small handful of positive sound effects are highlighted in blue, like the "projectile hit" tinkle or lore unlocks.
+
+## Completeness
+
+As of v1.21.4, I believe I have mapped all vanilla sounds to have audio descriptions. If I've missed any, instead of displaying a description like "Drifter groans," it'll show up as "creature/drifter-aggro." If you see any like this for **vanilla** sound effects, please let me know.
+
+## Compatibility
+
+Only vanilla sound effects are currently added. Any sound effects added by mods will show up with a placeholder/name.
+
+I'm happy to add support for some of the more popular mods myself, but I believe that any mod can add compatibility with this mod by adding caption keys to their language file. If you have a sound at `assets/yourmodid/sounds/creature/dave-singing.ogg`, you'd add a key like this to your language file:
+
+```json
+
+"captions:creature/dave-singing": "Dave sings",
+
+```
+
+But this is entirely untested. Let me know if you try it!
+
+If you want to add support for a sound effect to this mod, I welcome pull requests. For just adding audio descriptions, it's not too terribly technical, so don't be afraid to jump in and ask questions!
+
+## Limitations
+
+Like the original mod, currently there is no way to move or resize the captions dialog. This is planned for the unknown future, but pull requests are welcome.
+
+Currently, sounds' directions are pinned to where they start, so if the source of a sound moves while the sound is still playing, it will not update. A fix for this is planned.
+
+Related to this, sometimes sounds that occur at your location like "Footsteps" and "Armor clatters" will occasionally flicker as showing as behind you as you walk away from your footsteps.