axis_order.hpp File Reference

Per-source axis permutation and inversion applied to raw-to-physical IMU samples. More...

#include <cstdint>

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Classes
struct	m5::imu::AxisOrder
	Chip-frame-to-body-frame axis remap: a permutation plus a per-output-axis sign flip. More...

Namespaces
namespace	m5
	Top level namespace of M5Stack.

Enumerations
enum class	m5::imu::AxisPermutation : uint8_t {   XYZ , XZY , YXZ , YZX ,   ZXY , ZYX }
	Which raw axis feeds each output slot, read left-to-right. More...

Functions
const uint8_t *	m5::imu::axis_permutation_indices (const AxisPermutation p)
	Source-axis index feeding each output slot, for a given permutation.
AxisPermutation	m5::imu::permutation_from_indices (const uint8_t(&p)[3])
	Map a source-axis index triplet back to an AxisPermutation.
AxisOrder	m5::imu::compose (const AxisOrder &first, const AxisOrder &second)
	Compose two axis orders into one.

Detailed Description

Per-source axis permutation and inversion applied to raw-to-physical IMU samples.

Enumeration Type Documentation

AxisPermutation

enum class m5::imu::AxisPermutation : uint8_t

strong

Which raw axis feeds each output slot, read left-to-right.

e.g. YXZ means output[0] = raw Y, output[1] = raw X, output[2] = raw Z.

Enumerator
XYZ	Identity: output = (X, Y, Z)
XZY	output = (X, Z, Y)
YXZ	output = (Y, X, Z)
YZX	output = (Y, Z, X)
ZXY	output = (Z, X, Y)
ZYX	output = (Z, Y, X)

Function Documentation

axis_permutation_indices()

const uint8_t * m5::imu::axis_permutation_indices ( const AxisPermutation p )

inline

Source-axis index feeding each output slot, for a given permutation.

Parameters

p	Permutation

Returns

Pointer to a static 3-element array: out[i] = src[result[i]]

compose()

AxisOrder m5::imu::compose ( const AxisOrder & first, const AxisOrder & second )

inline

Compose two axis orders into one.

Parameters

first	Axis order applied first
second	Axis order applied second

Returns

An AxisOrder R such that R.apply(v) == second.apply(first.apply(v)) for every v

AxisOrder is a signed axis permutation, so the composition is itself an AxisOrder (no information is lost). Used by AhrsController to fold a global user axis order onto each source's fixed board correction without applying two transforms per sample.

permutation_from_indices()

AxisPermutation m5::imu::permutation_from_indices ( const uint8_t(&) p[3] )

inline

Map a source-axis index triplet back to an AxisPermutation.

Parameters

p	3-element array holding a permutation of {0,1,2} (out[i] = src[p[i]])

Returns

The matching AxisPermutation; AxisPermutation::XYZ if p is not a valid permutation