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Fixed the line-sphere intersection

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The original implementation had the same mistakes than the ray-sphere
intersection.
Added two new 'out' parameters to return both intersection ponits.
Changed the implementation to the geomethric method.
This commit is contained in:
boromisp 2012-11-11 23:53:10 +01:00
parent ed12134f34
commit 1683e78f58
2 changed files with 20 additions and 25 deletions
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5
glm/gtx/intersect.hpp
View File

@ -90,8 +90,9 @@ namespace glm
template <typename genType>
bool intersectLineSphere(
genType const & point0, genType const & point1,
genType const & center, typename genType::value_type radius,
genType & position, genType & normal);
genType const & sphereCenter, typename genType::value_type sphereRadius,
genType & intersectionPosition1, genType & intersectionNormal1,
genType & intersectionPosition2 = genType(), genType & intersectionNormal2 = genType());
/// @}
}//namespace glm

40
glm/gtx/intersect.inl
View File

@ -170,33 +170,27 @@ namespace glm
GLM_FUNC_QUALIFIER bool intersectLineSphere
(
genType const & point0, genType const & point1,
genType const & center, typename genType::value_type radius,
genType & position, genType & normal
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 = point1 - point0;
typename genType::value_type a = dot(dir, dir);
typename genType::value_type b = typename genType::value_type(2) * dot(center, dir);
typename genType::value_type c = dot(center, center) - radius * radius;
typename genType::value_type d = b * b - typename genType::value_type(4) * a * c;
typename genType::value_type e = sqrt(d);
typename genType::value_type x1 = (-b - e) / (typename genType::value_type(2) * a);
typename genType::value_type x2 = (-b + e) / (typename genType::value_type(2) * a);
if(x1 > 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 )
{
position = center + dir * radius;
normal = (position - center) / radius;
return true;
}
else if(x2 > Epsilon)
{
position = center + dir * radius;
normal = (position - center) / radius;
return true;
}
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