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.. default-domain:: C
euler angles
============
Header: cglm/euler.h
You may wonder what **glm_euler_sq** type ( **_sq** stands for sequence ) and
:c:func:`glm_euler_by_order` do.
I used them to convert euler angles in one coordinate system to another. For
instance if you have **Z_UP** euler angles and if you want to convert it
to **Y_UP** axis then :c:func:`glm_euler_by_order` is your friend. For more
information check :c:func:`glm_euler_order` documentation
You must pass arrays as array, if you use C compiler then you can use something
like this:
.. code-block:: c
float pitch, yaw, roll;
mat4 rot;
/* pitch = ...; yaw = ...; roll = ... */
glm_euler((vec3){pitch, yaw, roll}, rot);
Rotation Conveniention
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Current *cglm*'s euler functions uses these convention:
* Tait–Bryan angles (x-y-z convention)
* Intrinsic rotations (pitch, yaw and roll).
This is reserve order of extrinsic (elevation, heading and bank) rotation
* Right hand rule (actually all rotations in *cglm* use **RH**)
* All angles used in *cglm* are **RADIANS** not degrees
**NOTE**: The default :c:func:`glm_euler` function is the short name of
:c:func:`glm_euler_xyz` this is why you can't see :c:func:`glm_euler_xyz`.
When you see an euler function which doesn't have any X, Y, Z suffix then
assume that uses **_xyz** (or instead it accept order as parameter).
If rotation doesn't work properly, your options:
1. If you use (or paste) degrees convert it to radians before calling an euler function
.. code-block:: c
float pitch, yaw, roll;
mat4 rot;
/* pitch = degrees; yaw = degrees; roll = degrees */
glm_euler((vec3){glm_rad(pitch), glm_rad(yaw), glm_rad(roll)}, rot);
2. Convention mismatch. You may have extrinsic angles,
if you do (if you must) then consider to use reverse order e.g if you have
**xyz** extrinsic then use **zyx**
3. *cglm* may implemented it wrong, consider to create an issue to report it
or pull request to fix it
Table of contents (click to go):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Types:
1. glm_euler_sq
Functions:
1. :c:func:`glm_euler_order`
#. :c:func:`glm_euler_angles`
#. :c:func:`glm_euler`
#. :c:func:`glm_euler_xyz`
#. :c:func:`glm_euler_zyx`
#. :c:func:`glm_euler_zxy`
#. :c:func:`glm_euler_xzy`
#. :c:func:`glm_euler_yzx`
#. :c:func:`glm_euler_yxz`
#. :c:func:`glm_euler_by_order`
Functions documentation
~~~~~~~~~~~~~~~~~~~~~~~
.. c:function:: glm_euler_sq glm_euler_order(int ord[3])
| packs euler angles order to glm_euler_sq enum.
To use :c:func:`glm_euler_by_order` function you need *glm_euler_sq*. You
can get it with this function.
You can build param like this:
| X = 0, Y = 1, Z = 2
if you have ZYX order then you pass this: [2, 1, 0] = ZYX.
if you have YXZ order then you pass this: [1, 0, 2] = YXZ
As you can see first item specifies which axis will be first then the
second one specifies which one will be next an so on.
Parameters:
| *[in]* **ord** euler angles order [Angle1, Angle2, Angle2]
Returns:
packed euler order
.. c:function:: void glm_euler_angles(mat4 m, vec3 dest)
| extract euler angles (in radians) using xyz order
Parameters:
| *[in]* **m** affine transform
| *[out]* **dest** angles vector [x, y, z]
.. c:function:: void glm_euler(vec3 angles, mat4 dest)
| build rotation matrix from euler angles
this is alias of glm_euler_xyz function
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_xyz(vec3 angles, mat4 dest)
| build rotation matrix from euler angles
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_zyx(vec3 angles, mat4 dest)
| build rotation matrix from euler angles
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_zxy(vec3 angles, mat4 dest)
| build rotation matrix from euler angles
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_xzy(vec3 angles, mat4 dest)
| build rotation matrix from euler angles
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_yzx(vec3 angles, mat4 dest)
build rotation matrix from euler angles
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_yxz(vec3 angles, mat4 dest)
| build rotation matrix from euler angles
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **dest** rotation matrix
.. c:function:: void glm_euler_by_order(vec3 angles, glm_euler_sq ord, mat4 dest)
| build rotation matrix from euler angles with given euler order.
Use :c:func:`glm_euler_order` function to build *ord* parameter
Parameters:
| *[in]* **angles** angles as vector [Xangle, Yangle, Zangle]
| *[in]* **ord** euler order
| *[in]* **dest** rotation matrix
|
