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lib/glm/gtx/intersect.inl

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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 genType>
+	GLM_FUNC_QUALIFIER bool intersectRayTriangle
+	(
+		genType const & orig, genType const & dir,
+		genType const & v0, genType const & v1, genType const & v2,
+		genType & baryPosition
+	)
+	{
+		genType e1 = v1 - v0;
+		genType e2 = v2 - v0;
+
+		genType p = glm::cross(dir, e2);
+
+		typename genType::value_type a = glm::dot(e1, p);
+
+		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