Input

WolfEngine's input system handles button polling and analog joystick reading with built-in software debouncing. It supports up to 4 controllers simultaneously, each with buttons wired directly to GPIO pins, buttons routed through an I2C expander (PCF8574, PCF8575, or MCP23017), and an analog joystick via ADC — all configured from a single settings file.

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Accessing Input

Input is available anywhere in game code through the global Input() function. First get a reference to the controller you want to query, then call methods on it:

Controller* controller = nullptr;

void Start() override {
    controller = Input().getController(0); // player 1
}

void Update() override {
    if (controller && controller->getButtonDown<Button::A>()) {
        // do something
    }
}

Note: Always store the controller pointer in Start() rather than calling getController() every frame.

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Controllers

WolfEngine supports up to 4 simultaneous controllers. Each controller is configured independently in Input Settings.

Controller* p1 = Input().getController(0); // player 1
Controller* p2 = Input().getController(1); // player 2

getController() expects indices in the 0..3 range. Passing an out-of-range index will trigger a debug assert. It returns nullptr for disabled controller slots. Always null-check before use if unsure:

Controller* p2 = Input().getController(1);
    if (p2) {
    p2->getButtonDown<Button::A>();
}

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Buttons

WolfEngine supports 10 buttons per controller:

Button	Enum
A	Button::A
B	Button::B
C	Button::C
D	Button::D
E	Button::E
F	Button::F
G	Button::G
H	Button::H
I	Button::I
J	Button::J

Each button can be wired to a direct GPIO pin, an expander pin, or left unassigned — all configured in Input Settings.

Note: Button labels have no predefined meaning in the engine. They are just identifiers. Your controller may have ABXY, directions, or any other layout — wire them however you like and assign meaning in your game code.

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Button Queries

getButton<Button::B>()

Returns true every frame the button is held down.

if (controller && controller->getButton<Button::B>()) {
    player.accelerate();
}

getButtonDown<Button::B>()

Returns true only on the single frame the button is first pressed. Use this for one-shot actions.

if (controller && controller->getButtonDown<Button::A>()) {
    player.jump();
}

getButtonUp<Button::B>()

Returns true only on the single frame the button is released.

if (controller && controller->getButtonUp<Button::A>()) {
    player.stopCharging();
}

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Analog Joystick

The joystick returns a normalized float value per axis in the range -1.0 to +1.0. Values inside the dead zone return exactly 0.0 to prevent stick drift.

float x = controller->getAxis(JoyAxis::X);
float y = controller->getAxis(JoyAxis::Y);

Value	Meaning
-1.0	Full negative (left / down)
0.0	Center or inside dead zone
+1.0	Full positive (right / up)

Dead zone size and axis calibration are configured per controller in Input Settings. If a joystick axis is disabled, getAxis() always returns 0.0.

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Supported Expanders

Buttons can be routed through any of the following I2C expanders instead of direct GPIO:

Chip	Type	Pins	Address Range
PCF8574	8-bit, no registers	0–7	0x20–0x27
PCF8575	16-bit, no registers	0–15	0x20–0x27
MCP23017	16-bit, register-based	0–15	0x20–0x27

Expander type and address are configured per controller in Input Settings.

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Debouncing

All buttons across all controllers are automatically debounced in software. A button state change is only committed after the signal has remained stable for the duration defined by debounceMs in Input Settings. This prevents noise and contact bounce from registering false presses. Debounce timing is engine-wide and applies equally to all controllers.

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Configuration

All input routing, expander setup, joystick calibration, and controller enabling is done in WE_Settings.hpp. See Input Settings for the full reference.