To make your own mod you need to create subdirectory in **<datadir>/Mods/** with name that will be used as identifier for your mod.
Main mod is file called **mod.json** and should be placed into main folder of your mod, e.g. **Mods/myMod/mod.json**
All content of your mod should go into **Content** directory, e.g. **Mods/myMod/Content/**. Alternatively, it is possible to replace this directory with single .zip archive.
All VCMI configuration files use [JSON format](http://en.wikipedia.org/wiki/Json) so you may want to familiarize yourself with it first.
Mod.json is main file in your mod and must be present in any mod. This file contains basic description of your mod, dependencies or conflicting mods (if present), list of new content and so on.
- Referencing objects in bonus system: `"subtype" : "creature.archer"`. Bonus system requires explicit definition of object type since different bonuses may require different identifier class.
- Referencing object from specific mod: `"nativeTerrain" : "hota.cove:sorceress"`. In some cases, for example to resolve conflicts when multiple mods use same object name you might need to explicitly specify mod in which game needs to look up an identifier. Alternatively, you can use this form for clarity if you want to clearly specify that object comes from another mod.
Note that modification of existing objects does not requires a dependency on edited mod. Such definitions will only be used by game if corresponding mod is installed and active.
This allows using objects editing not just for rebalancing mods but also to provide compatibility between two different mods or to add interaction between two mods.
Any graphical replacer mods fall under this category. In VCMI directory **<modname>/Content** acts as mod-specific game root directory. So for example file **<modname>/Content/Data/AISHIELD.PNG** will replace file with same name from **H3Bitmap.lod** game archive.
Any other files can be replaced in exactly same way.
Note that replacing files from archives requires placing them into specific location:
- **Warning:** overriding graphical files from other mods is discouraged and may be removed in future versions of vcmi. Please use modification of existing objects instead.
Heroes III uses custom format for storing animation: def files. These files are used to store all in-game animations as well as for some GUI elements like buttons and for icon sets.
These files can be replaced by another def file but in some cases original format can't be used. This includes but not limited to:
In VCMI these animation files can also be replaced by json description of their content. See [Animation Format](Animation_Format.md) for full description of this format.
Mods list hosted under main VCMI organization: [vcmi-mods-repository](https://github.com/vcmi/vcmi-mods-repository).
Each mod hosted in it's own repository under separate organization [vcmi-mods](https://github.com/vcmi-mods). This way if engine become more popular in future we can create separate teams for each mod and accept as many people as needed.
- Engine developers get control over all mods and can easily update them without adding extra burden for modders / mod maintainers.
- With tools such as [GitHub Desktop](https://desktop.github.com/) it's easy for non-programmers to contribute.
- Forward and backward compatibility. Stable releases of game use compatible version of mods while users of daily builds will be able to test mods supporting bleeding edge features.
- Tracking of changes for repository and mods. It's not big deal now, but once we have scripting it's will be important to keep control over what code included in mods.
- GitHub also create ZIP archives for us so mods will be stored uncompressed and version can be identified by commit hash.
Our mod list in vcmi-mods-repository had "develop" as primary branch. Daily builds of VCMI use mod list file from this branch.
Once VCMI get stable release there will be branching into "1.0.0", "1.1.0", etc. Launcher of released version will request mod list for particular version.
Same way we can also create special stable branch for every mod under "vcmi-mods" organization umbrella once new stable version is released. So this way it's will be easier to maintain two versions of same mod: for stable and latest version.
Before your mod can be accepted into official mod list you need to get it into repository under "vcmi-mods" organization umbrella. To do this contact one of mod repository maintainers. If needed you can get own team within "vcmi-mods" organization.
Once you submitted certain commit into official mod list you are not allowed to rewrite history before that commit. This way we can make sure that VCMI launcher will always be able to download older version of any mod.
Branches such as "develop" or stable branches like "1.0.0" should be marked as protected on GitHub.
