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/// @ref gtx_intersect
/// @file glm/gtx/intersect.inl
namespace glm
{
template<typename genType>
GLM_FUNC_QUALIFIER bool intersectRayPlane
(
genType const& orig, genType const& dir,
genType const& planeOrig, genType const& planeNormal,
typename genType::value_type & intersectionDistance
)
{
typename genType::value_type d = glm::dot(dir, planeNormal);
typename genType::value_type Epsilon = std::numeric_limits<typename genType::value_type>::epsilon();
if(d < -Epsilon)
{
intersectionDistance = glm::dot(planeOrig - orig, planeNormal) / d;
return true;
}
return false;
}
template<typename T, qualifier Q>
GLM_FUNC_QUALIFIER bool intersectRayTriangle
(
vec<3, T, Q> const& orig, vec<3, T, Q> const& dir,
vec<3, T, Q> const& vert0, vec<3, T, Q> const& vert1, vec<3, T, Q> const& vert2,
vec<2, T, Q>& baryPosition, T& distance
)
{
// find vectors for two edges sharing vert0
vec<3, T, Q> const edge1 = vert1 - vert0;
vec<3, T, Q> const edge2 = vert2 - vert0;
// begin calculating determinant - also used to calculate U parameter
vec<3, T, Q> const p = glm::cross(dir, edge2);
// if determinant is near zero, ray lies in plane of triangle
T const det = glm::dot(edge1, p);
vec<3, T, Q> qvec;
if(det > std::numeric_limits<T>::epsilon())
{
// calculate distance from vert0 to ray origin
vec<3, T, Q> const tvec = orig - vert0;
// calculate U parameter and test bounds
baryPosition.x = glm::dot(tvec, p);
if(baryPosition.x < static_cast<T>(0) || baryPosition.x > det)
return false;
// prepare to test V parameter
qvec = glm::cross(tvec, edge1);
// calculate V parameter and test bounds
baryPosition.y = glm::dot(dir, qvec);
if((baryPosition.y < static_cast<T>(0)) || ((baryPosition.x + baryPosition.y) > det))
return false;
}
else if(det < -std::numeric_limits<T>::epsilon())
{
// calculate distance from vert0 to ray origin
vec<3, T, Q> const tvec = orig - vert0;
// calculate U parameter and test bounds
baryPosition.x = glm::dot(tvec, p);
if((baryPosition.x > static_cast<T>(0)) || (baryPosition.x < det))
return false;
// prepare to test V parameter
qvec = glm::cross(tvec, edge1);
// calculate V parameter and test bounds
baryPosition.y = glm::dot(dir, qvec);
if((baryPosition.y > static_cast<T>(0)) || (baryPosition.x + baryPosition.y < det))
return false;
}
else
return false; // ray is parallel to the plane of the triangle
T inv_det = static_cast<T>(1) / det;
// calculate distance, ray intersects triangle
distance = glm::dot(edge2, qvec) * inv_det;
baryPosition *= inv_det;
return true;
}
/*
typename genType::value_type Epsilon = std::numeric_limits<typename genType::value_type>::epsilon();
if(a < Epsilon && a > -Epsilon)
return false;
typename genType::value_type f = typename genType::value_type(1.0f) / a;
genType s = orig - v0;
baryPosition.x = f * glm::dot(s, p);
if(baryPosition.x < typename genType::value_type(0.0f))
return false;
if(baryPosition.x > typename genType::value_type(1.0f))
return false;
genType q = glm::cross(s, e1);
baryPosition.y = f * glm::dot(dir, q);
if(baryPosition.y < typename genType::value_type(0.0f))
return false;
if(baryPosition.y + baryPosition.x > typename genType::value_type(1.0f))
return false;
baryPosition.z = f * glm::dot(e2, q);
return baryPosition.z >= typename genType::value_type(0.0f);
}
*/
template<typename genType>
GLM_FUNC_QUALIFIER bool intersectLineTriangle
(
genType const& orig, genType const& dir,
genType const& vert0, genType const& vert1, genType const& vert2,
genType & position
)
{
typename genType::value_type Epsilon = std::numeric_limits<typename genType::value_type>::epsilon();
genType edge1 = vert1 - vert0;
genType edge2 = vert2 - vert0;
genType pvec = cross(dir, edge2);
float det = dot(edge1, pvec);
if (det > -Epsilon && det < Epsilon)
return false;
float inv_det = typename genType::value_type(1) / det;
genType tvec = orig - vert0;
position.y = dot(tvec, pvec) * inv_det;
if (position.y < typename genType::value_type(0) || position.y > typename genType::value_type(1))
return false;
genType qvec = cross(tvec, edge1);
position.z = dot(dir, qvec) * inv_det;
if (position.z < typename genType::value_type(0) || position.y + position.z > typename genType::value_type(1))
return false;
position.x = dot(edge2, qvec) * inv_det;
return true;
}
template<typename genType>
GLM_FUNC_QUALIFIER bool intersectRaySphere
(
genType const& rayStarting, genType const& rayNormalizedDirection,
genType const& sphereCenter, const typename genType::value_type sphereRadiusSquered,
typename genType::value_type & intersectionDistance
)
{
typename genType::value_type Epsilon = std::numeric_limits<typename genType::value_type>::epsilon();
genType diff = sphereCenter - rayStarting;
typename genType::value_type t0 = dot(diff, rayNormalizedDirection);
typename genType::value_type dSquared = dot(diff, diff) - t0 * t0;
if( dSquared > sphereRadiusSquered )
{
return false;
}
typename genType::value_type t1 = sqrt( sphereRadiusSquered - dSquared );
intersectionDistance = t0 > t1 + Epsilon ? t0 - t1 : t0 + t1;
return intersectionDistance > Epsilon;
}
template<typename genType>
GLM_FUNC_QUALIFIER bool intersectRaySphere
(
genType const& rayStarting, genType const& rayNormalizedDirection,
genType const& sphereCenter, const typename genType::value_type sphereRadius,
genType & intersectionPosition, genType & intersectionNormal
)
{
typename genType::value_type distance;
if( intersectRaySphere( rayStarting, rayNormalizedDirection, sphereCenter, sphereRadius * sphereRadius, distance ) )
{
intersectionPosition = rayStarting + rayNormalizedDirection * distance;
intersectionNormal = (intersectionPosition - sphereCenter) / sphereRadius;
return true;
}
return false;
}
template<typename genType>
GLM_FUNC_QUALIFIER bool intersectLineSphere
(
genType const& point0, genType const& point1,
genType const& sphereCenter, typename genType::value_type sphereRadius,
genType & intersectionPoint1, genType & intersectionNormal1,
genType & intersectionPoint2, genType & intersectionNormal2
)
{
typename genType::value_type Epsilon = std::numeric_limits<typename genType::value_type>::epsilon();
genType dir = normalize(point1 - point0);
genType diff = sphereCenter - point0;
typename genType::value_type t0 = dot(diff, dir);
typename genType::value_type dSquared = dot(diff, diff) - t0 * t0;
if( dSquared > sphereRadius * sphereRadius )
{
return false;
}
typename genType::value_type t1 = sqrt( sphereRadius * sphereRadius - dSquared );
if( t0 < t1 + Epsilon )
t1 = -t1;
intersectionPoint1 = point0 + dir * (t0 - t1);
intersectionNormal1 = (intersectionPoint1 - sphereCenter) / sphereRadius;
intersectionPoint2 = point0 + dir * (t0 + t1);
intersectionNormal2 = (intersectionPoint2 - sphereCenter) / sphereRadius;
return true;
}
}//namespace glm
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