Geometric functions
Core features

## Functions

template<typename T , qualifier Q>
GLM_FUNC_DECL GLM_CONSTEXPR vec< 3, T, Q > | cross (vec< 3, T, Q > const &x, vec< 3, T, Q > const &y)
| Returns the cross product of x and y. More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL T | distance (vec< L, T, Q > const &p0, vec< L, T, Q > const &p1)
| Returns the distance between p0 and p1, i.e., length(p0 - p1). More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL GLM_CONSTEXPR T | dot (vec< L, T, Q > const &x, vec< L, T, Q > const &y)
| Returns the dot product of x and y, i.e., result = x * y. More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL vec< L, T, Q > | faceforward (vec< L, T, Q > const &N, vec< L, T, Q > const &I, vec< L, T, Q > const &Nref)
| If dot(Nref, I) < 0.0, return N, otherwise, return -N. More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL T | length (vec< L, T, Q > const &x)
| Returns the length of x, i.e., sqrt(x * x). More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL vec< L, T, Q > | normalize (vec< L, T, Q > const &x)
| Returns a vector in the same direction as x but with length of 1. More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL vec< L, T, Q > | reflect (vec< L, T, Q > const &I, vec< L, T, Q > const &N)
| For the incident vector I and surface orientation N, returns the reflection direction : result = I - 2.0 * dot(N, I) * N. More...
template<length_t L, typename T , qualifier Q>
GLM_FUNC_DECL vec< L, T, Q > | refract (vec< L, T, Q > const &I, vec< L, T, Q > const &N, T eta)
| For the incident vector I and surface normal N, and the ratio of indices of refraction eta, return the refraction vector. More...

## Detailed Description

These operate on vectors as vectors, not component-wise.

Include <glm/geometric.hpp> to use these core features.

## Function Documentation

## cross()

GLM_FUNC_DECL GLM_CONSTEXPR vec<3, T, Q> glm::cross | ( | vec< 3, T, Q > const & | x,
|  | vec< 3, T, Q > const & | y
| ) |  |

Returns the cross product of x and y.

Template Parameters

  T | Floating-point scalar types.

See also
  GLSL cross man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## distance()

GLM_FUNC_DECL T glm::distance | ( | vec< L, T, Q > const & | p0,
|  | vec< L, T, Q > const & | p1
| ) |  |

Returns the distance between p0 and p1, i.e., length(p0 - p1).

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL distance man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## dot()

GLM_FUNC_DECL GLM_CONSTEXPR T glm::dot | ( | vec< L, T, Q > const & | x,
|  | vec< L, T, Q > const & | y
| ) |  |

Returns the dot product of x and y, i.e., result = x * y.

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL dot man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## faceforward()

GLM_FUNC_DECL vec<L, T, Q> glm::faceforward | ( | vec< L, T, Q > const & | N,
|  | vec< L, T, Q > const & | I,
|  | vec< L, T, Q > const & | Nref
| ) |  |

If dot(Nref, I) < 0.0, return N, otherwise, return -N.

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL faceforward man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## length()

GLM_FUNC_DECL T glm::length | ( | vec< L, T, Q > const & | x | ) |

Returns the length of x, i.e., sqrt(x * x).

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL length man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## normalize()

GLM_FUNC_DECL vec<L, T, Q> glm::normalize | ( | vec< L, T, Q > const & | x | ) |

Returns a vector in the same direction as x but with length of 1.

According to issue 10 GLSL 1.10 specification, if length(x) == 0 then result is undefined and generate an error.

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL normalize man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## reflect()

GLM_FUNC_DECL vec<L, T, Q> glm::reflect | ( | vec< L, T, Q > const & | I,
|  | vec< L, T, Q > const & | N
| ) |  |

For the incident vector I and surface orientation N, returns the reflection direction : result = I - 2.0 * dot(N, I) * N.

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL reflect man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions

## refract()

GLM_FUNC_DECL vec<L, T, Q> glm::refract | ( | vec< L, T, Q > const & | I,
|  | vec< L, T, Q > const & | N,
|  | T | eta
| ) |  |

For the incident vector I and surface normal N, and the ratio of indices of refraction eta, return the refraction vector.

Template Parameters

  L | An integer between 1 and 4 included that qualify the dimension of the vector.
  T | Floating-point scalar types.

See also
  GLSL refract man page
  GLSL 4.20.8 specification, section 8.5 Geometric Functions