GyroPad

Gyroscope and accelerometer processing library for game controllers, written in Odin.

Install

Copy all .odin files to your project:

types.odin
gamepad_motion.odin
motion.odin
calibration.odin
settings.odin

Import in your code:

import gm "path/to/gyro"

Usage

Initialize and process sensor data each frame:

gamepad := gm.Gamepad_Motion{}
gm.gamepad_motion_init(&gamepad)

gm.gamepad_motion_process(
    &gamepad,
    gyro_x, gyro_y, gyro_z,
    accel_x, accel_y, accel_z,
    delta_time,
)

orientation := gm.get_orientation(&gamepad)
gravity := gm.get_gravity(&gamepad)
accel := gm.get_processed_acceleration(&gamepad)
gyro := gm.get_calibrated_gyro(&gamepad)

Player-Space Gyro

Gyro relative to the controller's orientation (pitch and roll):

pitch, yaw := gm.get_player_space_gyro(&gamepad)
pitch, yaw := gm.get_player_space_gyro(&gamepad, 1.5)

World-Space Gyro

Gyro relative to world gravity (useful for camera control):

pitch, yaw := gm.get_world_space_gyro(&gamepad)
pitch, yaw := gm.get_world_space_gyro(&gamepad, 0.1)

Calibration

Auto-Calibration

Enable stillness detection (controller at rest):

gm.set_calibration_mode(&gamepad, {.Stillness})

Enable sensor fusion (accelerometer-gyro fusion):

gm.set_calibration_mode(&gamepad, {.Sensor_Fusion})

Enable both:

gm.set_calibration_mode(&gamepad, {.Stillness, .Sensor_Fusion})

Continuous Calibration

Start/pause/reset continuous gyro bias tracking:

gm.start_continuous_calibration(&gamepad)
gm.pause_continuous_calibration(&gamepad)
gm.reset_continuous_calibration(&gamepad)

Manual Calibration

Set calibration offset directly:

gm.set_calibration_offset(&gamepad, offset_x, offset_y, offset_z, weight)
offset := gm.get_calibration_offset(&gamepad)

Check calibration state:

confidence := gm.get_auto_calibration_confidence(&gamepad)
is_steady := gm.get_auto_calibration_is_steady(&gamepad)
gm.set_auto_calibration_confidence(&gamepad, 0.5)

Configuration

Adjust motion settings via Gamepad_Motion_Settings:

gamepad.settings.gravity_correction_still_speed = 1.0
gamepad.settings.gravity_correction_shaky_speed = 0.1
gamepad.settings.stillness_calibration_half_time = 0.1
gamepad.settings.sensor_fusion_confidence_rate = 1.0

See settings.odin for all options. Use DEFAULT_SETTINGS for reasonable defaults.

Coordinate System

Y-up (following PlayStation controller convention). Gyro in degrees per second. Accelerometer in g-force (1 g ≈ 9.8 m/s²).

Data Types

Vec3 :: [3]f32

Quat :: struct {
    w, x, y, z: f32,
}

Gamepad_Motion :: struct {
    settings: Gamepad_Motion_Settings,
    gyro: Vec3,
    raw_accel: Vec3,
    motion: Motion,
    gyro_calibration: Gyro_Calibration,
    auto_calibration: Auto_Calibration,
    current_calibration_mode: Calibration_Mode_Set,
    is_calibrating: bool,
}

License

MIT License.