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(glm::abs(d) > Epsilon)  // if dir and planeNormal are not perpendicular
        {
            typename genType::value_type const tmp_intersectionDistance =   glm::dot(planeOrig - orig, planeNormal) / d;
            if (tmp_intersectionDistance > static_cast<typename genType::value_type>(0)) { // allow only intersections
                intersectionDistance = tmp_intersectionDistance;
                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> Perpendicular(0);
 
        if(det > std::numeric_limits<T>::epsilon())
        {
            // calculate distance from vert0 to ray origin
            vec<3, T, Q> const dist = orig - vert0;
 
            // calculate U parameter and test bounds
            baryPosition.x = glm::dot(dist, p);
            if(baryPosition.x < static_cast<T>(0) || baryPosition.x > det)
                return false;
 
            // prepare to test V parameter
            Perpendicular = glm::cross(dist, edge1);
 
            // calculate V parameter and test bounds
            baryPosition.y = glm::dot(dir, Perpendicular);
            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 dist = orig - vert0;
 
            // calculate U parameter and test bounds
            baryPosition.x = glm::dot(dist, p);
            if((baryPosition.x > static_cast<T>(0)) || (baryPosition.x < det))
                return false;
 
            // prepare to test V parameter
            Perpendicular = glm::cross(dist, edge1);
 
            // calculate V parameter and test bounds
            baryPosition.y = glm::dot(dir, Perpendicular);
            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, Perpendicular) * inv_det;
        baryPosition *= inv_det;
 
        return true;
    }
 
    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 Perpendicular = cross(dir, edge2);
 
        float det = dot(edge1, Perpendicular);
 
        if (det > -Epsilon && det < Epsilon)
            return false;
        typename genType::value_type inv_det = typename genType::value_type(1) / det;
 
        genType Tengant = orig - vert0;
 
        position.y = dot(Tengant, Perpendicular) * inv_det;
        if (position.y < typename genType::value_type(0) || position.y > typename genType::value_type(1))
            return false;
 
        genType Cotengant = cross(Tengant, edge1);
 
        position.z = dot(dir, Cotengant) * 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, Cotengant) * 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