Update Reverse Engineering - Textures

Reverse Engineering - Textures.-.md

@@ -1,9 +1,22 @@
 ## General
 
-Textures are usually split into two data blobs:
+There seem to be two ways that a texture can be stored in a bundle "data file" vs "stream file".
 
-- Metadata and a small mipmap directly in the bundle
+- "data file":
-- All other mipmaps in stream files
+  - points to a file in `data/` without `.stream` extension
+  - size of the file in `data/` can range from 200 bytes to several MB -> no apparent correlation
+  - `external == true`, no data in bundle
+- "stream file":
+  - points to a `.stream` file in `data/`
+  - data file size can range from 90 bytes to several MB
+  - always contains data in the bundle file, size ranging from 200 bytes to several KB
+
+In the case of stream files, the bundle will contain metadata (e.g. DDS headers) and a small mipmap, while the data file will contain the other mipmaps.
+
+Other things of note:
+
+- `BundleFileHeader.unknown_1` is always `1`
+- textures can be duplicated across bundles
 
 ### Formats