initial import, >900commits predate this

docs/framework/engine/engine.md

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+# Engine
+
+The Engine is the heart of the MushMachine framework.
+It holds the Storage of all [`MM::Service`](services.md)s, update callbacks and is responsible for calling them.
+
+# Usage
+
+Provides a forwarding header `<mm/engine_fwd.hpp>`.
+
+## Construction
+
+The `MM::Engine` provides a Constructor which accepts a time interval, in which `.fixedUpdate()` is called. The Default is 1/60.
+
+## Starting
+```cpp
+#include <mm/engine.hpp>
+
+MM::Engine engine;
+
+// add and enable MM::Services here
+
+engine.run();
+```
+
+The `MM::Engine` disables all enabled `MM::Service`s in reverse order on destruction or `.cleanup()`.
+
+## Managing [`MM::Service`](services.md)s
+
+### Adding a `MM::Service`
+
+Before a `MM::Service` can be enabled, it needs to be added to the engine.
+`.addService<MyService>(my, args)` adds a service and forwards args to its constructor.
+There is currently no way of removing a `MM::Service`.
+
+### Getting a `MM::Service`
+
+You can get a Pointer via `.tryService<MyService>()` and an asserted reference via `.getService<MyService>()`. If the `MM::Service` does not exist, it returns a `nullptr. "Enablement Status" makes no difference.
+
+### Provide a `MM::Service` (Interfaces)
+
+`.provide<MyServiceInterface, MyService>()` registers `MyService` also as `MyServiceInterface`, so `MyService` becomes getable via `MyServiceInterface`. `MyService` needs to be added beforehand.
+
+### Enabling/Disabling a `MM::Service`
+
+`MM::Service`s can be Enabled/Disabled during `.run()` as a deferred operation (see `.addFixedDefer(...)`)
+
+* `.enableService<MyService>()` calles the `.enable()` of `MyService`. Also returns `true` on success.
+* `.disableService<MyService>()` calles the `.disable()` of `MyService`.
+There are also overloads, which accept a type id.
+
+## Update / FixedUpdate
+
+FixedUpdates are called with update interval (default 1/60, set on engine ctr), while Updates are called "as fast as possible". Since Rendering is usually done using Update and blocks on VSync, this is as fast as VSync.
+
+Since fixedUpdate callbacks don't get a time delta, querying `.getFixedDeltaTime()` is mandatory.
+
+### adding Update callbacks
+
+`.addUpdate(MyFn)` and `.addFixedUpdate(MyFn)` add `MyFn` as an update and fixedUpdate respectively and return a `FunctionDataHandle`(ptr) to remove them again.
+
+### removing Update callbacks
+
+`.removeUpdate(myHandle)` and `.removeFixedUpdate(myHandle)` remove those callbacks again.
+
+### `.run()`
+
+`.run()` is a blocking call, which calles `.fixedUpdate()` in a fixed interval with an accumulator. Inbetween those `.fixedUpdate()`s, `.update()` gets called "as fast as possible".
+
+You don't need to call `.run()`, instead you can call `.update()` and `.fixedUpdate()` yourself.
+
+### `.stop()`
+
+Stops the Engine...
+Actually quits the loop in `.run()`.
+

docs/framework/engine/interfaces.md

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+# Default Shipped Interfaces
+
+### Index
+
+* `MM::Services::SceneServiceInterface`
+
+
+## SceneServiceInterface
+
+Not very stable. But I use it all over the place.
+
+It uses [`EnTT`](https://github.com/skypjack/entt).
+
+### interface
+
+Use `.getScene()` to get current `MM::Scene`.
+
+Use `.changeScene(newScene)` to queue `.changeSceneNow(newScene)`.
+
+Use `.changeSceneNow(newScene)` to change currently held `MM::Scene`.
+
+Use `.addSystemToScene(fn)` to add a `MM::System` to the `MM::Scene`.
+

docs/framework/engine/services.md

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+# Services
+
+`MM::Service`s are the Components that get added to the `MM::Engine`.
+
+They need to extend `MM::Service` (included in `<mm/engine.hpp>`) and implement the following Interface:
+
+* Destructor (since it is virtual)
+* `bool enable(MM::Engine& engine)`
+* `void disable(MM::Engine& engine)`
+
+and optionally
+
+* `const char* name(void)`
+
+Not implementing `name()` does not impact functionality, but it is not good practise.
+
+Update and FixedUpdate callbacks should only be added in `enable()` and should be removed in `disable()`.
+