cglm/docs/source/vec3.rst

.. default-domain:: C

vec3
====

Header: cglm/vec3.h

 **Important:** *cglm* was used **glm_vec_** namespace for vec3 functions until
 **v0.5.0**, since **v0.5.0** cglm uses **glm_vec3_** namespace for vec3.

 Also `glm_vec3_flipsign` has been renamed to `glm_vec3_negate`

We mostly use vectors in graphics math, to make writing code faster
and easy to read, some *vec3* functions are aliased in global namespace.
For instance :c:func:`glm_dot` is alias of :c:func:`glm_vec3_dot`,
alias means inline wrapper here. There is no call version of alias functions

There are also functions for rotating *vec3* vector. **_m4**, **_m3** prefixes
rotate *vec3* with matrix.

Table of contents (click to go):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Macros:

1. glm_vec3_dup(v, dest)
#. GLM_VEC3_ONE_INIT
#. GLM_VEC3_ZERO_INIT
#. GLM_VEC3_ONE
#. GLM_VEC3_ZERO
#. GLM_YUP
#. GLM_ZUP
#. GLM_XUP

Functions:

1. :c:func:`glm_vec3`
#. :c:func:`glm_vec3_copy`
#. :c:func:`glm_vec3_zero`
#. :c:func:`glm_vec3_one`
#. :c:func:`glm_vec3_dot`
#. :c:func:`glm_vec3_norm2`
#. :c:func:`glm_vec3_norm`
#. :c:func:`glm_vec3_add`
#. :c:func:`glm_vec3_adds`
#. :c:func:`glm_vec3_sub`
#. :c:func:`glm_vec3_subs`
#. :c:func:`glm_vec3_mul`
#. :c:func:`glm_vec3_scale`
#. :c:func:`glm_vec3_scale_as`
#. :c:func:`glm_vec3_div`
#. :c:func:`glm_vec3_divs`
#. :c:func:`glm_vec3_addadd`
#. :c:func:`glm_vec3_subadd`
#. :c:func:`glm_vec3_muladd`
#. :c:func:`glm_vec3_muladds`
#. :c:func:`glm_vec3_maxadd`
#. :c:func:`glm_vec3_minadd`
#. :c:func:`glm_vec3_flipsign`
#. :c:func:`glm_vec3_flipsign_to`
#. :c:func:`glm_vec3_inv`
#. :c:func:`glm_vec3_inv_to`
#. :c:func:`glm_vec3_negate`
#. :c:func:`glm_vec3_negate_to`
#. :c:func:`glm_vec3_normalize`
#. :c:func:`glm_vec3_normalize_to`
#. :c:func:`glm_vec3_cross`
#. :c:func:`glm_vec3_crossn`
#. :c:func:`glm_vec3_distance2`
#. :c:func:`glm_vec3_distance`
#. :c:func:`glm_vec3_angle`
#. :c:func:`glm_vec3_rotate`
#. :c:func:`glm_vec3_rotate_m4`
#. :c:func:`glm_vec3_rotate_m3`
#. :c:func:`glm_vec3_proj`
#. :c:func:`glm_vec3_center`
#. :c:func:`glm_vec3_maxv`
#. :c:func:`glm_vec3_minv`
#. :c:func:`glm_vec3_ortho`
#. :c:func:`glm_vec3_clamp`
#. :c:func:`glm_vec3_lerp`
#. :c:func:`glm_vec3_make`
#. :c:func:`glm_vec3_faceforward`
#. :c:func:`glm_vec3_reflect`
#. :c:func:`glm_vec3_refract`

Functions documentation
~~~~~~~~~~~~~~~~~~~~~~~

.. c:function:: void  glm_vec3(vec4 v4, vec3 dest)

    init vec3 using vec4

    Parameters:
      | *[in]*  **v4**    vector4
      | *[out]* **dest**  destination

.. c:function:: void  glm_vec3_copy(vec3 a, vec3 dest)

    copy all members of [a] to [dest]

    Parameters:
      | *[in]*  **a**     source
      | *[out]* **dest**  destination

.. c:function:: void  glm_vec3_zero(vec3 v)

    makes all members 0.0f (zero)

    Parameters:
      | *[in, out]*  **v**     vector

.. c:function:: void  glm_vec3_one(vec3 v)

    makes all members 1.0f (one)

    Parameters:
      | *[in, out]*  **v**     vector

.. c:function:: float  glm_vec3_dot(vec3 a, vec3 b)

    dot product of vec3

    Parameters:
      | *[in]*  **a**  vector1
      | *[in]*  **b**  vector2

    Returns:
      dot product

.. c:function:: void  glm_vec3_cross(vec3 a, vec3 b, vec3 d)

    cross product of two vector (RH)

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  destination

.. c:function:: void  glm_vec3_crossn(vec3 a, vec3 b, vec3 dest)

    cross product of two vector (RH) and normalize the result

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  destination

.. c:function:: float  glm_vec3_norm2(vec3 v)

    norm * norm (magnitude) of vector

    we can use this func instead of calling norm * norm, because it would call
    sqrtf function twice but with this func we can avoid func call, maybe this is
    not good name for this func

    Parameters:
      | *[in]*  **v**   vector

    Returns:
      square of norm / magnitude

.. c:function:: float  glm_vec3_norm(vec3 vec)

    | euclidean norm (magnitude), also called L2 norm
    | this will give magnitude of vector in euclidean space

    Parameters:
      | *[in]*  **vec**   vector

.. c:function:: void  glm_vec3_add(vec3 a, vec3 b, vec3 dest)

    add a vector to b vector store result in dest

    Parameters:
      | *[in]*  **a**     vector1
      | *[in]*  **b**     vector2
      | *[out]* **dest**  destination vector

.. c:function:: void  glm_vec3_adds(vec3 a, float s, vec3 dest)

    add scalar to v vector store result in dest (d = v + vec(s))

    Parameters:
      | *[in]*  **v**     vector
      | *[in]*  **s**     scalar
      | *[out]* **dest**  destination vector

.. c:function:: void  glm_vec3_sub(vec3 v1, vec3 v2, vec3 dest)

    subtract b vector from a vector store result in dest (d = v1 - v2)

    Parameters:
      | *[in]*  **a**     vector1
      | *[in]*  **b**     vector2
      | *[out]* **dest**  destination vector

.. c:function:: void  glm_vec3_subs(vec3 v, float s, vec3 dest)

    subtract scalar from v vector store result in dest (d = v - vec(s))

    Parameters:
      | *[in]*  **v**     vector
      | *[in]*  **s**     scalar
      | *[out]* **dest**  destination vector

.. c:function:: void  glm_vec3_mul(vec3 a, vec3 b, vec3 d)

    multiply two vector (component-wise multiplication)

    Parameters:
      | *[in]*  **a**     vector
      | *[in]*  **b**     scalar
      | *[out]* **d**     result = (a[0] * b[0], a[1] * b[1], a[2] * b[2])

.. c:function:: void glm_vec3_scale(vec3 v, float s, vec3 dest)

     multiply/scale vec3 vector with scalar: result = v * s


    Parameters:
      | *[in]*  **v**     vector
      | *[in]*  **s**     scalar
      | *[out]* **dest**  destination vector

.. c:function:: void  glm_vec3_scale_as(vec3 v, float s, vec3 dest)

    make vec3 vector scale as specified: result = unit(v) * s

    Parameters:
      | *[in]*  **v**     vector
      | *[in]*  **s**     scalar
      | *[out]* **dest**  destination vector

.. c:function:: void  glm_vec3_div(vec3 a, vec3 b, vec3 dest)

    div vector with another component-wise division: d = a / b

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  result = (a[0] / b[0], a[1] / b[1], a[2] / b[2])

.. c:function:: void  glm_vec3_divs(vec3 v, float s, vec3 dest)

    div vector with scalar: d = v / s

    Parameters:
      | *[in]*  **v**     vector
      | *[in]*  **s**     scalar
      | *[out]* **dest**  result = (a[0] / s, a[1] / s, a[2] / s])

.. c:function:: void  glm_vec3_addadd(vec3 a, vec3 b, vec3 dest)

    | add two vectors and add result to sum
    | it applies += operator so dest must be initialized

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  dest += (a + b)

.. c:function:: void  glm_vec3_subadd(vec3 a, vec3 b, vec3 dest)

    | sub two vectors and add result to sum
    | it applies += operator so dest must be initialized

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  dest += (a - b)

.. c:function:: void  glm_vec3_muladd(vec3 a, vec3 b, vec3 dest)

    | mul two vectors and add result to sum
    | it applies += operator so dest must be initialized

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  dest += (a * b)

.. c:function:: void  glm_vec3_muladds(vec3 a, float s, vec3 dest)

    | mul vector with scalar and add result to sum
    | it applies += operator so dest must be initialized

    Parameters:
      | *[in]*  **a**     vector
      | *[in]*  **s**     scalar
      | *[out]* **dest**  dest += (a * b)

.. c:function:: void  glm_vec3_maxadd(vec3 a, vec3 b, vec3 dest)

    | add max of two vector to result/dest
    | it applies += operator so dest must be initialized

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  dest += (a * b)

.. c:function:: void  glm_vec3_minadd(vec3 a, vec3 b, vec3 dest)

    | add min of two vector to result/dest
    | it applies += operator so dest must be initialized

    Parameters:
      | *[in]*  **a**     vector 1
      | *[in]*  **b**     vector 2
      | *[out]* **dest**  dest += (a * b)

.. c:function:: void  glm_vec3_flipsign(vec3 v)

    **DEPRECATED!**

    use :c:func:`glm_vec3_negate`

    Parameters:
      | *[in, out]*  **v**    vector

.. c:function:: void  glm_vec3_flipsign_to(vec3 v, vec3 dest)

    **DEPRECATED!**

    use :c:func:`glm_vec3_negate_to`

    Parameters:
      | *[in]*  **v**       vector
      | *[out]* **dest**    negated vector

.. c:function:: void  glm_vec3_inv(vec3 v)

    **DEPRECATED!**

    use :c:func:`glm_vec3_negate`

    Parameters:
      | *[in, out]*  **v**    vector

.. c:function:: void  glm_vec3_inv_to(vec3 v, vec3 dest)

    **DEPRECATED!**

    use :c:func:`glm_vec3_negate_to`

    Parameters:
      | *[in]*  **v**     source
      | *[out]* **dest**  destination

.. c:function:: void  glm_vec3_negate(vec3 v)

    negate vector components

    Parameters:
      | *[in, out]*  **v**    vector

.. c:function:: void  glm_vec3_negate_to(vec3 v, vec3 dest)

    negate vector components and store result in dest

    Parameters:
      | *[in]*  **v**       vector
      | *[out]* **dest**    negated vector

.. c:function:: void  glm_vec3_normalize(vec3 v)

    normalize vec3 and store result in same vec

    Parameters:
      | *[in, out]*  **v**    vector

.. c:function:: void  glm_vec3_normalize_to(vec3 vec, vec3 dest)

     normalize vec3 to dest

    Parameters:
      | *[in]*   **vec**   source
      | *[out]*  **dest**  destination

.. c:function:: float  glm_vec3_angle(vec3 v1, vec3 v2)

    angle between two vector

    Parameters:
      | *[in]*  **v1**   vector1
      | *[in]*  **v2**   vector2

    Return:
      | angle as radians

.. c:function:: void  glm_vec3_rotate(vec3 v, float angle, vec3 axis)

     rotate vec3 around axis by angle using Rodrigues' rotation formula

    Parameters:
      | *[in, out]*  **v**      vector
      | *[in]*       **axis**   axis vector (will be normalized)
      | *[in]*       **angle**  angle (radians)

.. c:function:: void  glm_vec3_rotate_m4(mat4 m, vec3 v, vec3 dest)

    apply rotation matrix to vector

    Parameters:
      | *[in]*  **m**     affine matrix or rot matrix
      | *[in]*  **v**     vector
      | *[out]* **dest**  rotated vector

.. c:function:: void  glm_vec3_rotate_m3(mat3 m, vec3 v, vec3 dest)

    apply rotation matrix to vector

    Parameters:
      | *[in]*  **m**     affine matrix or rot matrix
      | *[in]*  **v**     vector
      | *[out]* **dest**  rotated vector

.. c:function:: void  glm_vec3_proj(vec3 a, vec3 b, vec3 dest)

    project a vector onto b vector

    Parameters:
      | *[in]*  **a**     vector1
      | *[in]*  **b**     vector2
      | *[out]* **dest**  projected vector

.. c:function:: void  glm_vec3_center(vec3 v1, vec3 v2, vec3 dest)

    find center point of two vector

    Parameters:
      | *[in]*  **v1**    vector1
      | *[in]*  **v2**    vector2
      | *[out]* **dest**  center point

.. c:function:: float  glm_vec3_distance2(vec3 v1, vec3 v2)

    squared distance between two vectors

    Parameters:
      | *[in]*  **v1**  vector1
      | *[in]*  **v2**  vector2

    Returns:
      | squared distance (distance * distance)

.. c:function:: float  glm_vec3_distance(vec3 v1, vec3 v2)

    distance between two vectors

    Parameters:
      | *[in]*  **v1**  vector1
      | *[in]*  **v2**  vector2

    Returns:
      | distance

.. c:function:: void  glm_vec3_maxv(vec3 v1, vec3 v2, vec3 dest)

    max values of vectors

    Parameters:
      | *[in]*  **v1**    vector1
      | *[in]*  **v2**    vector2
      | *[out]* **dest**  destination

.. c:function:: void  glm_vec3_minv(vec3 v1, vec3 v2, vec3 dest)

    min values of vectors

    Parameters:
      | *[in]*  **v1**    vector1
      | *[in]*  **v2**    vector2
      | *[out]* **dest**  destination

.. c:function:: void  glm_vec3_ortho(vec3 v, vec3 dest)

    possible orthogonal/perpendicular vector

    References:
      * `On picking an orthogonal vector (and combing coconuts) <http://lolengine.net/blog/2013/09/21/picking-orthogonal-vector-combing-coconuts>`_

    Parameters:
      | *[in]*  **v**     vector
      | *[out]* **dest**  orthogonal/perpendicular vector

.. c:function:: void  glm_vec3_clamp(vec3 v, float minVal, float maxVal)

    constrain a value to lie between two further values

    Parameters:
      | *[in, out]*  **v**       vector
      | *[in]*       **minVal**  minimum value
      | *[in]*       **maxVal**  maximum value

.. c:function:: void  glm_vec3_lerp(vec3 from, vec3 to, float t, vec3 dest)

    linear interpolation between two vector

    | formula:  from + s * (to - from)

    Parameters:
      | *[in]*  **from**   from value
      | *[in]*  **to**     to value
      | *[in]*  **t**      interpolant (amount) clamped between 0 and 1
      | *[out]* **dest**   destination

.. c:function:: void glm_vec3_make(const float * __restrict src, vec3 dest)

    Create three dimensional vector from pointer

    .. note::: **@src** must contain at least 3 elements.

    Parameters:
      | *[in]*  **src**  pointer to an array of floats
      | *[out]* **dest** destination vector

.. c:function:: void glm_vec3_faceforward(vec3 N, vec3 I, vec3 Nref, vec3 dest)

    A vector pointing in the same direction as another

    Parameters:
      | *[in]*  **N**     vector to orient
      | *[in]*  **I**     incident vector
      | *[in]*  **Nref**  reference vector
      | *[out]* **dest**  destination: oriented vector, pointing away from the surface.

.. c:function:: void glm_vec3_reflect(vec3 I, vec3 N, vec3 dest) 

    Reflection vector using an incident ray and a surface normal

    Parameters:
      | *[in]*  **I**     incident vector
      | *[in]*  **N**     *❗️ normalized ❗️* normal vector
      | *[out]* **dest**  destination: reflection result

.. c:function:: bool glm_vec3_refract(vec3 I, vec3 N, float eta, vec3 dest)

    
    Computes refraction vector for an incident vector and a surface normal.
   
    Calculates the refraction vector based on Snell's law. If total internal reflection
    occurs (angle too great given eta), dest is set to zero and returns false.
    Otherwise, computes refraction vector, stores it in dest, and returns true.

    Parameters:
      | *[in]*  **I**     *❗️ normalized ❗️* incident vector
      | *[in]*  **N**     *❗️ normalized ❗️* normal vector
      | *[in]*  **eta**   ratio of indices of refraction (incident/transmitted)
      | *[out]* **dest**  refraction vector if refraction occurs; zero vector otherwise

    Returns:
      returns true if refraction occurs; false if total internal reflection occurs.