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- /// @ref gtx_intersect
- 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
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