Quaternion

#include <graphics/quat.h>

struct quat

Two component quaternion structure.

float quat.x

X component

float quat.y

Y component

float quat.z

Z component

float quat.w

W component

float quat.ptr[4]

Unioned array of all components

void quat_identity(struct quat *dst)

Sets a quaternion to {0.0f, 0.0f, 0.0f, 1.0f}.

Parameters:

• dst – Destination

void quat_set(struct quat *dst, float x, float y)

Sets the individual components of a quaternion.

Parameters:

• dst – Destination

• x – X component

• y – Y component

• y – Z component

• w – W component

void quat_copy(struct quat *dst, const struct quat *v)

Copies a quaternion

Parameters:

• dst – Destination

• v – Quaternion to copy

void quat_add(struct quat *dst, const struct quat *v1, const struct quat *v2)

Adds two quaternions

Parameters:

• dst – Destination

• v1 – Quaternion 1

• v2 – Quaternion 2

void quat_sub(struct quat *dst, const struct quat *v1, const struct quat *v2)

Subtracts two quaternions

Parameters:

• dst – Destination

• v1 – Quaternion being subtracted from

• v2 – Quaternion being subtracted

void quat_mul(struct quat *dst, const struct quat *v1, const struct quat *v2)

Multiplies two quaternions

Parameters:

• dst – Destination

• v1 – Quaternion 1

• v2 – Quaternion 2

void quat_addf(struct quat *dst, const struct quat *v, float f)

Adds a floating point to all components

Parameters:

• dst – Destination

• dst – Quaternion

• f – Floating point

void quat_subf(struct quat *dst, const struct quat *v, float f)

Subtracts a floating point from all components

Parameters:

• dst – Destination

• v – Quaternion being subtracted from

• f – Floating point being subtracted

void quat_mulf(struct quat *dst, const struct quat *v, float f)

Multiplies a floating point with all components

Parameters:

• dst – Destination

• dst – Quaternion

• f – Floating point

void quat_inv(struct quat *dst, const struct quat *v)

Inverts a quaternion

Parameters:

• dst – Destination

• v – Quaternion to invert

float quat_dot(const struct quat *v1, const struct quat *v2)

Performs a dot product between two quaternions

Parameters:

• v1 – Quaternion 1

• v2 – Quaternion 2

Returns:

Result of the dot product

float quat_len(const struct quat *v)

Gets the length of a quaternion

Parameters:

• v – Quaternion

Returns:

The quaternion’s length

float quat_dist(const struct quat *v1, const struct quat *v2)

Gets the distance between two quaternions

Parameters:

• v1 – Quaternion 1

• v2 – Quaternion 2

Returns:

Distance between the two quaternions

void quat_from_axisang(struct quat *dst, const struct axisang *aa)

Converts an axis angle to a quaternion

Parameters:

• dst – Destination quaternion

• aa – Axis angle

void quat_from_matrix4(struct quat *dst, const struct matrix4 *m)

Converts the rotational properties of a matrix to a quaternion

Parameters:

• dst – Destination quaternion

• m – Matrix to convert

void quat_get_dir(struct vec3 *dst, const struct quat *q)

Converts a quaternion to a directional vector

Parameters:

• dst – Destination 3-component vector

• q – Quaternion

void quat_set_look_dir(struct quat *dst, const struct vec3 *dir)

Creates a quaternion from a specific “look” direction

Parameters:

• dst – Destination quaternion

• dir – 3-component vector representing the look direction

void quat_interpolate(struct quat *dst, const struct quat *q1, const struct quat *q2, float t)

Linearly interpolates two quaternions

Parameters:

• dst – Destination quaternion

• q1 – Quaternion 1

• q2 – Quaternion 2

• t – Time value (0.0f..1.0f)

void quat_get_tangent(struct quat *dst, const struct quat *prev, const struct quat *q, const struct quat *next)

Gets a tangent value for the center of three rotational values

Parameters:

• dst – Destination quaternion

• prev – Previous rotation

• q – Rotation to get tangent for

• next – Next rotation

void quat_interpolate_cubic(struct quat *dst, const struct quat *q1, const struct quat *q2, const struct quat *m1, const struct quat *m2, float t)

Performs cubic interpolation between two quaternions

Parameters:

• dst – Destination quaternion

• q1 – Quaternion 1

• q2 – Quaternion 2

• m1 – Tangent 1

• m2 – Tangent 2

• t – Time value (0.0f..1.0f)