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Merge pull request #659 from CaptainCarrot/QuatLookAt

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Added a quaternion-based "Look At" function #659
This commit is contained in:
Christophe 2017-07-24 12:05:18 +02:00 committed by GitHub
commit a61483b34a
3 changed files with 80 additions and 0 deletions
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28
glm/gtx/quaternion.hpp
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@ -177,6 +177,34 @@ namespace glm
vec<3, T, P> const & orig,
vec<3, T, P> const & dest);
/// Build a look at quaternion based on the default handedness.
///
/// @param direction Desired direction of the camera.
/// @param up Up vector, how the camera is oriented. Typically (0, 1, 0).
template<typename T, precision P>
GLM_FUNC_DECL tquat<T, P> quatLookAt(
tvec3<T, P> const & direction,
tvec3<T, P> const & up);
/// Build a right-handed look at quaternion.
///
/// @param direction Desired direction of the camera.
/// @param up Up vector, how the camera is oriented. Typically (0, 1, 0).
template<typename T, precision P>
GLM_FUNC_DECL tquat<T, P> quatLookAtRH(
tvec3<T, P> const & direction,
tvec3<T, P> const & up);
/// Build a left-handed look at quaternion.
///
/// @param eye Position of the camera
/// @param direction Desired direction onto which the +z-axis gets mapped
/// @param up Up vector, how the camera is oriented. Typically (0, 1, 0).
template<typename T, precision P>
GLM_FUNC_DECL tquat<T, P> quatLookAtLH(
tvec3<T, P> const & direction,
tvec3<T, P> const & up);
/// Returns the squared length of x.
///
/// @see gtx_quaternion

34
glm/gtx/quaternion.inl
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@ -209,4 +209,38 @@ namespace glm
rotationAxis.z * invs);
}
template<typename T, precision P>
GLM_FUNC_QUALIFIER tquat<T, P> quatLookAt(tvec3<T, P> const& direction, tvec3<T, P> const& up)
{
# if GLM_COORDINATE_SYSTEM == GLM_LEFT_HANDED
return quatLookAtLH(direction, up);
# else
return quatLookAtRH(direction, up);
# endif
}
template<typename T, precision P>
GLM_FUNC_QUALIFIER tquat<T, P> quatLookAtRH(tvec3<T, P> const& direction, tvec3<T, P> const& up)
{
tmat3x3<T, P> Result(uninitialize);
Result[2] = -normalize(direction);
Result[0] = normalize(cross(up, Result[2]));
Result[1] = cross(Result[2], Result[0]);
return quat_cast(Result);
}
template<typename T, precision P>
GLM_FUNC_QUALIFIER tquat<T, P> quatLookAtLH(tvec3<T, P> const& direction, tvec3<T, P> const& up)
{
tmat3x3<T, P> Result(uninitialize);
Result[2] = normalize(direction);
Result[0] = normalize(cross(up, Result[2]));
Result[1] = cross(Result[2], Result[0]);
return quat_cast(Result);
}
}//namespace glm

18
test/gtx/gtx_quaternion.cpp
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@ -90,6 +90,23 @@ int test_log()
return Error;
}
int test_quat_lookAt()
{
int Error(0);
glm::vec3 eye(0.0f);
glm::vec3 center(1.1f, -2.0f, 3.1416f);
glm::vec3 up = glm::vec3(-0.17f, 7.23f, -1.744f);
glm::quat test_quat = glm::quatLookAt(center - eye, up);
glm::quat test_mat = glm::conjugate(glm::quat_cast(glm::lookAt(eye, center, up)));
Error += static_cast<int>(glm::abs(glm::length(test_quat) - 1.0f) > glm::epsilon<float>());
Error += static_cast<int>(glm::min(glm::length(test_quat + (-test_mat)), glm::length(test_quat + test_mat)) > glm::epsilon<float>());
return Error;
}
int main()
{
int Error = 0;
@ -98,6 +115,7 @@ int main()
Error += test_rotation();
Error += test_quat_fastMix();
Error += test_quat_shortMix();
Error += test_quat_lookAt();
return Error;
}