Add initial draft of components documentation

docs/OatComponents.md

@@ -1,24 +1,114 @@
 # OAT Components
 
-## Building tools
-### RawTemplater
-### ZoneCodeGenerator
+The OpenAssetTools project consists of a handful of components.
 
 ## Tools
+
 ### Linker
+
+The **Linker** tool allows building custom fastfiles (.ff) for the supported games.
+It can also load existing zones and reuse their assets from in-memory.
+Only a subset of assets can be read from disk however, depending on the game.
+
+This tool has a CLI.
+For a list of all args, run `Linker --help`.
+
 ### Unlinker
 
+The **Unlinker** tool allows loading any fastfile (.ff) of supported games and works standalone.
+While being able to load any asset it can currently only dump a subset of these assets to disk, depending on the game.
+The formats of the dumped assets are either as close as possible to the originally used formats for these games or a commonly used format.
+
+This tool can be used either by drag-and-dropping and fastfile onto it or using its CLI.
+For a list of all args, run `Unlinker --help`.
+
+To be able to extract images from IWDs you need to add their containing folder to the search path.
+For example: `./Unlinker.exe -v --search-path "C:/Cod/IW4x/main" "C:/Cod/IW4x/zone/english/common_mp.ff"`
+
+## Building tools
+
+These are tools that are part of the building process of OAT.
+They are compiled first and then being run in the later stages of compiling the project.
+
+### RawTemplater
+
+The RawTemplater allows generating files based on a template with a c precompiler like language.
+The template allows the definition of variants in the form of properties that can be either true/false or have a range of values.
+For each resulting cartesian product of these properties a file is generated unless skipped.
+
+This is used for generating raw files for the shader pipeline.
+An example of a template files can be found [here (particle_cloud.techset.template)](../raw/iw4/techsets/particle_cloud.techset.template).
+
+### ZoneCodeGenerator
+
+The ZoneCodeGenerator generates code for loading and writing asset structs from and to fastfiles.
+It is very apparent that the original developers must have used a very similar technique of code generation therefore this aims
+to replicate what they might have done.
+Since nothing about this code generation is known however this implementation is entirely custom and results in code that fits into
+the code base of OAT only.
+
+The tool takes in a C header file and a commands file.
+The c header files is parsed for structs and unions to base the code on.
+The commands file describes further information necessary for code generation that is not possible to know just from the structs.
+
+The parsing of the c header file and the commands file is implemented using the Parser component.
+The format of the commands file is entirely custom to OAT.
+
+An example of a commands file can be found [here (IW4_Commands.txt)](../src/ZoneCode/Game/IW4/IW4_Commands.txt)
+
 ## Shared components
 
+These components split up code for reuse over the different tools.
+
 ### Common
+
+This component contains code that is shared between other Obj based and Zone based components.
+
 ### Crypto
+
+This component contains wrappers around used crypto and hashing third party libraries. 
+
 ### ObjCommon
+
+This component contains code that is used for both loading and writing asset data from and to disk. 
+
 ### ObjLoading
+
+This component contains code that is used for loading asset data from disk.
+
 ### ObjWriting
+
+This component contains code that is used for writing asset data to disk.
+
 ### Parser
+
+This component offers a custom Parser and Lexer implementation for parsing text based languages.
+It also includes commonly used patterns and preprocessors for Parsers in the project.
+
+Arguably there shouldn't be a custom parser implementation for this, but instead a more accepted dependency like ANTLR.
+However, I wanted to write my own implementations for science so here we are.
+
 ### Utils
+
+This component contains various utility code that is used in other tools or components.
+
 ### ZoneCode
+
+This component contains files necessary for generating code used for loading/writing from/to fastfiles.
+
 ### ZoneCodeGeneratorLib
+
+This component contains most of the code of ZoneCodeGenerator other than the CLI.
+Can be used as a static lib.
+
 ### ZoneCommon
+
+This component bundles code for both loading and writing from/to fastfiles. 
+
 ### ZoneLoading
-### ZoneWriting
+
+This component handles loading data from fastfiles.
+
+### ZoneWriting
+
+This component handles writing data to fastfiles.