10 files changed, 442 insertions, 0 deletions
diff --git a/src/doc/feature/animator_creation.dox b/src/doc/feature/animator_creation.dox
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/doc/feature/animator_creation.dox
diff --git a/src/doc/feature/bgm.dox b/src/doc/feature/bgm.dox
new file mode 100644
index 0000000..968abb8
--- /dev/null
+++ b/src/doc/feature/bgm.dox
@@ -0,0 +1,22 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_bgm Playing background music
+\ingroup feature
+\brief Add background music to a scene using the AudioSource component
+
+This page shows how to implement background music using the AudioSource
+effects.
+
+\see AudioSource
+
+\par Example
+
+\note This example assumes you already have a GameObject. If not, read
+\"\ref feature_gameobject\" first.
+
+\todo Merge #60
+
+*/
+}
diff --git a/src/doc/feature/config.dox b/src/doc/feature/config.dox
new file mode 100644
index 0000000..ae3a054
--- /dev/null
+++ b/src/doc/feature/config.dox
@@ -0,0 +1,61 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_config Engine configuration
+\ingroup feature
+\brief Configure default values and global options
+
+Default values and options that apply to the engine globally are read from a
+singleton struct named Config.
+
+\see Config
+
+\par Example
+
+Configuration options may be set individually or by assigning a [designated
+initializer list][desginit]. All of Config's members have default values and can
+safely be omitted from initializer lists.
+
+[desginit]: https://en.cppreference.com/w/cpp/language/aggregate_initialization#Designated_initializers
+
+```cpp
+#include <crepe/api/Config.h>
+
+int main() {
+	auto & config = crepe::Config::get_instance();
+
+	// Designated initializer list
+	config = {
+		// specify options here
+	};
+
+	// Reset default options
+	config = {};
+
+	// Set specific option
+	config.log.color = false;
+}
+```
+
+\par Options
+
+\noop Display config properties in monospace font
+\htmlonly
+<style>
+tr td:first-child { font-family: monospace; }
+</style>
+\endhtmlonly
+
+|Option|Description|
+|-|-|
+|\ref Config::asset::root_pattern ".asset.root_pattern"|\copybrief Config::asset::root_pattern|
+|\ref Config::log::color ".log.color"|\copybrief Config::log::color|
+|\ref Config::log::level ".log.level"|\copybrief Config::log::level|
+|\ref Config::physics::gravity ".physics.gravity"|\copybrief Config::physics::gravity|
+|\ref Config::savemgr::location ".savemgr.location"|\copybrief Config::savemgr::location|
+|\ref Config::window_settings::default_size ".window_settings.default_size"|\copybrief Config::window_settings::default_size|
+|\ref Config::window_settings::window_title ".window_settings.window_title"|\copybrief Config::window_settings::window_title|
+
+*/
+}
diff --git a/src/doc/feature/gameobject.dox b/src/doc/feature/gameobject.dox
new file mode 100644
index 0000000..ac3927c
--- /dev/null
+++ b/src/doc/feature/gameobject.dox
@@ -0,0 +1,18 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_gameobject Entity basics
+\ingroup feature
+\brief Building game entities using a GameObject
+
+GameObjects are the fundamental building blocks of a Scene. They represent entities
+in the game world and can have various components attached to them to define their
+behavior and properties. GameObjects can be created and modified within the
+Scene, allowing for a flexible and dynamic game environment.
+
+\see Component
+\see Scene
+
+*/
+}
diff --git a/src/doc/feature/proxy.dox b/src/doc/feature/proxy.dox
new file mode 100644
index 0000000..66bbd2f
--- /dev/null
+++ b/src/doc/feature/proxy.dox
@@ -0,0 +1,43 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_proxy Proxy utility
+\ingroup feature
+\brief Use ValueBroker as if it were a regular variable
+
+Proxy provides operators that allow you to use a ValueBroker instance as if it
+were a regular variable. Proxy implements a constructor that allows it to be
+used as a substitute return type for any function that returns ValueBroker.
+
+\see ValueBroker
+\see Proxy
+
+\par Example
+
+```cpp
+#include <crepe/util/Proxy.h>
+#include <crepe/ValueBroker.h>
+
+int calculation(int value) {
+	return 3 * value;
+}
+
+void anywhere() {
+	crepe::ValueBroker<int> foo_handle;
+	crepe::Proxy foo = foo_handle;
+
+	// implicitly calls .set()
+	foo += 10;
+
+	// implicitly calls .get()
+	int out = calculation(foo);
+
+	// explicitly cast (also calls .get())
+	int casted = int(foo);
+}
+
+```
+
+*/
+}
diff --git a/src/doc/feature/savemgr.dox b/src/doc/feature/savemgr.dox
new file mode 100644
index 0000000..6aeab03
--- /dev/null
+++ b/src/doc/feature/savemgr.dox
@@ -0,0 +1,80 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_savemgr Save data
+\ingroup feature
+\brief Functions to persistently store and retrieve arbitrary values
+
+The SaveManager may be used to persistently store game state such as player
+progress, statistics, achievements, etc. It works like a key-value store, where
+the key is a string and the value is an arbitrary type.
+
+SaveManager implements the following:
+
+- Storage and retrieval of primitive types and strings.
+- Automatic initialization of the database using default values.
+- The underlying database format is journaled, which reduces the likelihood of
+	players losing save data when an unexpected crash occurs while the SaveManager
+	is writing to disk.
+
+\see SaveManager
+
+\par Example
+
+The SaveManager instance reference may be retrieved by calling \c
+get_save_manager(). This function is available---
+
+- Within (derivatives of) Script
+
+- \todo Within (derivatives of) Scene
+
+- \todo As a public member function of LoopManager
+
+```cpp
+// Retrieve save manager
+crepe::SaveManager & save_manager = get_save_manager();
+```
+
+SaveManager may be used *explicitly*, using the \ref SaveManager::set "set()",
+\ref SaveManager::get "get()" and  \ref SaveManager::has "has()" methods:
+```cpp
+// Check if the key "foo" exists, and initialize it to 3 if it doesn't
+if (!save_manager.has("foo"))
+	save_manager.set<int>("foo", 3);
+// Get value of key "foo"
+int foo = save_manager.get<int>("foo");
+
+// ~~~ arbitrary game code ~~~
+foo += 10;
+// ~~~ arbitrary game code ~~~
+
+// Save "foo" back to database
+save_manager.set<int>("foo", foo);
+```
+
+Alternatively, SaveManager::get may be called with a default value as second
+parameter. This changes its return type to ValueBroker, which acts as a
+read/write handle to the specific key requested, and remembers the key and its
+value type for you:
+```cpp
+// Get a read/write handle to the value stored in key "foo", and initialize it
+// to 3 if it doesn't exist yet
+ValueBroker foo_handle = save_manager.get<int>("foo", 3);
+int foo = foo_handle.get();
+
+// ~~~ arbitrary game code ~~~
+foo += 10;
+// ~~~ arbitrary game code ~~~
+
+// Save back to database
+foo_handle.set(foo);
+```
+
+To further simplify game code, the return value of SaveManager::get may be
+implicitly cast to Proxy instead of ValueBroker. This allows the database value
+to be used as if it were a regular variable. This usage is detailed separately
+in \"\ref feature_proxy\".
+
+*/
+}
diff --git a/src/doc/feature/scene.dox b/src/doc/feature/scene.dox
new file mode 100644
index 0000000..b680eec
--- /dev/null
+++ b/src/doc/feature/scene.dox
@@ -0,0 +1,69 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_scene Scenes
+\ingroup feature
+\brief User-defined scenes
+
+Scenes can be used to implement game environments, and allow arbitrary game
+objects to be organized as part of the game structure. Scenes are implemented as
+derivative classes of Scene, which are added to the game using the SceneManager.
+Scenes describe the start of a Scene and cannot modify GameObjects during
+runtime of a Scene (use \ref feature_script for this purpose).
+
+\see SceneManager
+\see GameObject
+\see Script
+\see Scene
+
+\par Example
+
+This example demonstrates how to define and add scenes to the loop/scene manager
+in the `crepe` framework. Each concrete scene should be derived from Scene. In
+the example below, the concrete scene is named MyScene. A concrete scene should,
+at least, implement (override) two methods, namely load_scene() and get_name().
+The scene is build (using GameObjects) in the load_scene() method. GameObjects
+should be made using the component_manager::new_object().
+
+In the example below, two GameObjects (named object1 and object2) are added to
+MyScene. object1 and object2 do not have any non-default Components attached to
+them, however, if needed, this should also be done in load_scene(). Each
+concrete scene must have a unique name. This unique name is used to load a new
+concrete scene (via a Script). The unique name is set using the get_name()
+method. In the example below, MyScene's unique name is my_scene.
+
+After setting up one or more concrete scene(s), the concrete scene(s) should be
+added to the loop/scene manager. This is done in your main(). Firstly, the
+LoopManager should be instantiated. Than, all the concrete scene(s) should be
+added to the loop/scene manger via loop_mgr::add_scene<>(). The templated
+argument should define the concrete scene to be added.
+
+```cpp
+#include <crepe/api/Engine.h>
+#include <crepe/api/Scene.h>
+
+using namespace crepe;
+
+class MyScene : public Scene {
+public:
+	void load_scene() {
+		GameObject object1 = new_object("object1", "tag_my_scene", vec2{0, 0}, 0, 1);
+		GameObject object2 = new_object("object2", "tag_my_scene", vec2{1, 0}, 0, 1);
+	}
+
+	string get_name() const { return "my_scene"; }
+};
+
+int main() {
+	Engine foo;
+	
+	// Add the scenes to the loop manager
+	foo.add_scene<MyScene>();
+
+	return foo.main();
+}
+```
+
+*/
+}
diff --git a/src/doc/feature/script.dox b/src/doc/feature/script.dox
new file mode 100644
index 0000000..162b0f5
--- /dev/null
+++ b/src/doc/feature/script.dox
@@ -0,0 +1,68 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_script Scripting basics
+\ingroup feature
+\brief Create a concrete Script and attach it to a GameObject
+
+Scripts can be used to implement game behavior, and allow arbitrary code to run
+as part of the game loop. Scripts are implemented as derivative classes of
+Script, which are added to \ref GameObject "game objects" using the \ref
+BehaviorScript \ref Component "component".
+
+\see Script
+\see BehaviorScript
+\see GameObject
+
+\par Example
+
+\note This example assumes you already have a GameObject. If not, read
+\"\ref feature_gameobject\" first.
+
+First, define a class (anywhere) that inherits from Script. The Script class
+acts as an interface, and has three functions (\ref Script::init "\c init()",
+\ref Script::fixed_update "\c fixed_update()" and \ref Script::frame_update
+"\c frame_update()"), which *may* be implemented (they are empty by default).
+From now on, this derivative class will be referred to as a *concrete script*.
+
+```cpp
+#include <crepe/api/Script.h>
+#include <crepe/api/BehaviorScript.h>
+
+class MyScript : public crepe::Script {
+	void init() {
+		// called once
+	}
+
+	void fixed_update(crepe::duration_t delta_time) {
+		// called on fixed update
+	}
+	void frame_update(crepe::duration_t delta_time) {
+		// called for every rendered frame
+	}
+};
+```
+
+After defining a concrete script, it can be instantiated and attached to \ref
+feature_gameobject "game objects" during \ref feature_scene
+"scene initialization" using a BehaviorScript component:
+
+```cpp
+using namespace crepe;
+GameObject obj;
+
+// Create a BehaviorScript component to hold MyScript
+BehaviorScript & behavior_script = obj.add_component<BehaviorScript>();
+
+// Instantiate (and attach) MyScript to behavior_script
+behavior_script.set_script<MyScript>();
+```
+
+The above can also be done in a single call for convenience:
+```cpp
+obj.add_component<BehaviorScript>().set_script<MyScript>();
+```
+
+*/
+}
diff --git a/src/doc/feature/script_ecs.dox b/src/doc/feature/script_ecs.dox
new file mode 100644
index 0000000..8bd3376
--- /dev/null
+++ b/src/doc/feature/script_ecs.dox
@@ -0,0 +1,57 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_script_ecs Using ECS inside Script
+\ingroup feature
+\brief Query the component manager inside a concrete Script
+
+Script provides several methods to request references to components during
+runtime. These methods may be used in cases where it is either not practical or
+impossible to manually pass the references required to implement a certain
+behavior.
+
+\see Script
+\see ComponentManager
+
+\par Example
+
+\note This example assumes you already have a concrete Script. If not, read
+\"\ref feature_script\" first.
+
+The component manager can be queried for components inside Script using the
+following methods:
+
+- For requesting components on the same GameObject as this Script instance:
+	- Script::get_component(): \copybrief Script::get_component
+	- Script::get_components(): \copybrief Script::get_components
+- For requesting components in the current Scene:
+	- Script::get_components_by_id(): \copybrief Script::get_components_by_id
+	- Script::get_components_by_name(): \copybrief Script::get_components_by_name
+	- Script::get_components_by_tag(): \copybrief Script::get_components_by_tag
+
+```cpp
+#include <crepe/util/Log.h>
+#include <crepe/api/Script.h>
+#include <crepe/api/Metadata.h>
+
+using namespace crepe;
+
+class MyScript : public Script {
+	void show_self() {
+		Metadata & own_metadata = get_component<Metadata>();
+		logf("My name is {}", own_metadata.name);
+	}
+
+	void list_enemies() {
+		RefVector<Metadata> enemies = get_components_by_tag<Metadata>("enemy");
+		logf("There are {} enemies:", enemies.size());
+		for (const Metadata & enemy : enemies) {
+			logf("- {}", enemy.name);
+		}
+	}
+};
+```
+
+*/
+}
diff --git a/src/doc/feature/sfx.dox b/src/doc/feature/sfx.dox
new file mode 100644
index 0000000..2a5c9cc
--- /dev/null
+++ b/src/doc/feature/sfx.dox
@@ -0,0 +1,24 @@
+// vim:ft=doxygen
+namespace crepe {
+/**
+
+\defgroup feature_sfx Playing sound effects
+\ingroup feature
+\brief Fire a sound effect using the AudioSource component
+
+This page shows how to implement one-shot sound effects using the AudioSource
+component's 'fire and forget'-style API.
+
+\see AudioSource
+
+\par Example
+
+\note This example assumes you already have a GameObject to attach the
+AudioSource component to, and uses a Script to control the AudioSource instance.
+Separate pages describing these features in more detail can be found at \"\ref
+feature_gameobject\" and \"\ref feature_script\" respectively.
+
+\todo Merge #60
+
+*/
+}