bn::core namespace
#include <bn_core.h>

Core related functions.

Functions

void init(): This function must be called before using Butano, and it must be called only once.
void init(const string_view& keypad_commands): This function must be called before using Butano, and it must be called only once.
auto skip_frames() -> int: Returns the number of frames to skip.
void set_skip_frames(int skip_frames): Sets the number of frames to skip.
void update(): Updates the screen and all Butano subsystems.
void sleep(keypad::key_type wake_up_key): Sleeps the GBA until the given keypad key is pressed.
void sleep(const span<const keypad::key_type>& wake_up_keys): Sleeps the GBA until the given keypad keys are pressed.
void reset(): Resets the GBA, going back to the start of main().
auto current_cpu_usage() -> fixed: Returns the current CPU usage.
auto last_cpu_usage() -> fixed: Returns the CPU usage of the last elapsed frame.
auto last_vblank_usage() -> fixed: Returns the V-Blank usage of the last elapsed frame.
auto last_missed_frames() -> int: Returns the number of screen refreshes that were missed in the last core::update call.
auto vblank_callback() -> vblank_callback_type: Returns the user function called in V-Blank.
void set_vblank_callback(vblank_callback_type vblank_callback): Sets the user function called in V-Blank.
auto slow_game_pak() -> bool: Indicates if a slow game pak like the SuperCard SD has been detected or not.
auto system_font() -> const system_font&: Returns the font used to show assert and profiling messages.
void set_system_font(const bn::system_font& font): Sets the font used to show assert and profiling messages.
auto assert_tag() -> const string_view&: Returns the tag displayed in assert messages.
void set_assert_tag(const string_view& assert_tag): Sets the tag displayed in assert messages.

Function documentation

void bn::core::init(const string_view& keypad_commands)

This function must be called before using Butano, and it must be called only once.

Parameters
keypad_commands	Keypad commands recorded with the keypad logger.

Instead of reading the keypad of the GBA, these keypad commands are replayed.

int bn::core::skip_frames()

Returns the number of frames to skip.

0 skip frames means ~60 frames per second, 1 skip frame means ~30 frames per second, and so on.

void bn::core::set_skip_frames(int skip_frames)

Sets the number of frames to skip.

0 skip frames means ~60 frames per second, 1 skip frame means ~30 frames per second, and so on.

void bn::core::reset()

Resets the GBA, going back to the start of main().

Keep in mind that it doesn't rewind the stack, so alive objects are not destroyed.

fixed bn::core::current_cpu_usage()

Returns the current CPU usage.

A CPU usage greater than 1 means that at least one screen refresh should have been missed.

fixed bn::core::last_cpu_usage()

Returns the CPU usage of the last elapsed frame.

A CPU usage greater than 1 means that at least one screen refresh should have been missed.

If you only want to retrieve the number of missed screen refreshes, core::last_missed_frames is more accurate.

fixed bn::core::last_vblank_usage()

Returns the V-Blank usage of the last elapsed frame.

A V-Blank usage greater than 1 means that the screen is being redrawn before all of GBA display components being updated.

bn::core namespace #include <bn_core.h>