Input¶

#include "chili/input.hpp"

Three small helpers for the input code every game writes.

pressed() means held

In 32blit, blit::pressed(button) is true while the button is held. A button that went down this frame is in blit::buttons.pressed. Menus that use pressed() skip several rows per tap. These helpers read the right one.

Reference¶

Function	Does
`bool just_pressed(uint32_t button)`	True on the frame the button went down.
`bool menu_nav(int &index, int count, uint32_t pressed = buttons.pressed)`	Up/down moves `index` in `0..count-1`, with wrap-around. True when it moved.
`Repeat(uint32_t delay_ms = 250, uint32_t rate_ms = 80)`	Auto-repeat for held buttons.
`uint32_t Repeat::update(uint32_t dt)`	Call once per update. Returns the buttons that fire this frame.
`uint32_t Repeat::update(uint32_t held, uint32_t dt)`	Same, with your own held buttons (for example `scenes.held()`).
`bool Repeat::fired(uint32_t button)`	Whether the button fired on the last update.
`void Repeat::reset()`	Forget held buttons, for example when a round starts.

just_pressed¶

if(chili::just_pressed(Button::A)) jump();

The same as buttons.pressed & Button::A, with a name that says what it means.

menu_nav¶

int choice = 0;

void update(uint32_t time) {
  if(chili::menu_nav(choice, 3)) audio::play_sfx(sfx_move);
}

Index	Up	Down
0	2	1
1	0	2
2	1	0

Pass your own pressed to filter input, for example chili::menu_nav(choice, 3, scenes.pressed()). For a full menu with values and actions, use Menu.

Repeat¶

Holding a direction should move once, wait, then keep moving: like a key on a keyboard. Tetris pieces, a cursor on a board and letter pickers all want this.

chili::Repeat repeat(200, 60);  // wait 200 ms, then every 60 ms

void update(uint32_t time) {
  repeat.update(10);  // 32blit calls update() every 10 ms
  if(repeat.fired(Button::DPAD_LEFT)) piece.x--;
  if(repeat.fired(Button::DPAD_RIGHT)) piece.x++;
  if(repeat.fired(Button::DPAD_DOWN)) piece.y++;
}

How it fires while a button is held (delay 200 ms, rate 60 ms):

gantt
    dateFormat x
    axisFormat %L ms
    section Held
    button down        :0, 440
    section Fires
    press              :milestone, 0, 0
    after delay        :milestone, 200, 200
    repeat             :milestone, 260, 260
    repeat             :milestone, 320, 320
    repeat             :milestone, 380, 380
    repeat             :milestone, 440, 440

Each button is timed on its own, so holding left and then pressing down fires down right away.
After a long frame (a stall), it fires once and skips the missed repeats, so a piece does not jump.
Releasing the button starts the delay over.

The defaults, 250 ms then every 80 ms, feel right for menus and cursors.