Loop & Input API

Headers: src/loop/loopScheduler.h, src/system/input/inputMapper.h, src/system/input/inputEvent.h
Namespaces: glitter::loop, glitter::input

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glitter::loop::LoopScheduler

Manages per-frame callbacks for the engine's main loop. Retrieve via engine::loop().

Callback types

src/loop/loopScheduler.h

using RenderCallback = std::function<void(float dt)>;           // dt = frame delta seconds
using EventCallback  = std::function<void(const SDL_Event&)>;
using InputCallback  = std::function<void(const input::InputEvent&)>;

Registering callbacks

Multiple callbacks can be registered per slot; they are called in registration order.

Member	Returns	Description
onPreRender(cb)	void	Called before rendering each frame. Use for game logic, physics, animation.
onRender(cb)	void	Called during the render phase
onPostRender(cb)	void	Called after rendering — use for UI, debug overlays, ImGui panels
onEvent(cb)	void	Called for every raw SDL_Event (window resize, mouse button, etc.)
onInput(cb)	void	Called for every translated semantic InputEvent

Input access

Member	Returns	Description
inputMapper()	InputMapper&	Direct access to the input mapper for axis polling

Frame dispatch (called by engine::run())

These are called by the engine loop — game code does not call them directly.

Member	Returns	Description
runPreRender(dt)	void	Dispatch all pre-render callbacks
runRender(dt)	void	Dispatch all render callbacks
runPostRender(dt)	void	Dispatch all post-render callbacks
dispatchEvent(ev)	void	Translate an SDL event to input events and dispatch to all callbacks

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glitter::loop::TickGroup

Thread-affinity tag for future multi-threading support. Currently informational — all groups execute on the main thread.

Value	Future purpose
Render	Vsync-rate render thread
Logic	Fixed-rate game logic thread (e.g. 30 Hz)
Physics	Fixed-rate physics simulation thread
UI	Event-driven UI thread

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glitter::input::InputMapper

Translates raw SDL events into semantic InputEvent values using a loaded KeybindScheme. Retrieve via engine::input() or LoopScheduler::inputMapper().

Constructor

Methods

Member	Returns	Description
applyScheme(scheme)	void	Replace all key→action and key→axis bindings with those from scheme. Also sets mouse-look mode from scheme.mouseLook.
translate(sdlEvent)	std::vector<InputEvent>	Map a raw SDL event to zero or more semantic InputEvent values
getAxis(axis)	float	Poll a keyboard-driven axis in [-1, 1]. ScrollWheel is fire-once and always returns 0 here — read it from the dispatched AxisEvent instead.
beginFrame()	void	Called once per frame before callbacks. Reserved for gamepad polling.

KeybindScheme

Field	Type	Default	Description
name	std::string	""	Scheme identifier
mouseLook	bool	true	Enable relative mouse mode (hides cursor) when this scheme is active
keyActions	map<SDL_Keycode, Action>	{}	Key → discrete action bindings
keyAxes	map<SDL_Keycode, AxisBinding>	{}	Key → axis contribution bindings (e.g. W → {MoveZ, +1.0})

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glitter::input::InputEvent

Semantic event produced by InputMapper::translate(). A std::variant over three event types:

src/system/input/inputEvent.h

using InputEvent = std::variant<ActionEvent, AxisEvent, WindowResized>;

ActionEvent

Field	Type	Description
action	Action	The bound action
pressed	bool	true on key-down, false on key-up

AxisEvent

Field	Type	Description
axis	Axis	The bound axis
value	float	Keyboard axes: the scaled key contribution. Mouse: pixel delta.

WindowResized

Field	Type	Description
width	int	New window width in pixels
height	int	New window height in pixels

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glitter::input::Action

Discrete actions that can be bound to keys:

Value	Description
ToggleFXAA	Toggle FXAA anti-aliasing
ToggleFullscreen	Toggle fullscreen mode
SpeedBoost	Multiply free-fly camera movement speed (typically Shift)

glitter::input::Axis

Continuous axes for polling or binding:

Value	Description
MoveX	Strafe left/right (A = -1, D = +1)
MoveZ	Move forward/back (W = +1, S = -1)
MoveY	Move up/down (Q = +1, E = -1)
LookX	Mouse horizontal delta
LookY	Mouse vertical delta
ScrollWheel	Mouse scroll — fire-once, not polled via getAxis