split the function into two (95159f28) · Commits · XRFLab109 / Allpix Squared

src/tools/liang_barsky.h

+18 −3

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@
		#include <Math/Vector3D.h>

		#include <optional>
		#include <utility>

		namespace allpix {

		@@ -35,7 +36,8 @@ namespace allpix {
		* direction from the given position.
		*
		*/
		inline std::optional<ROOT::Math::XYZPoint> LiangBarskyClosestIntersection(const ROOT::Math::XYZVector& direction,

		inline std::optional<std::pair<double, double>> LiangBarskyIntersectionDistances(const ROOT::Math::XYZVector& direction,
		const ROOT::Math::XYZPoint& position,
		const ROOT::Math::XYZVector& box) {

		@@ -70,8 +72,21 @@ namespace allpix {
		clip(direction.Z(), -position.Z() - box.Z() / 2, t0, t1) &&
		clip(-direction.Z(), position.Z() - box.Z() / 2, t0, t1);

		if(intersect) {
		return std::make_pair(t0, t1);
		}
		return std::nullopt;
		}

		inline std::optional<ROOT::Math::XYZPoint> LiangBarskyClosestIntersection(const ROOT::Math::XYZVector& direction,
		const ROOT::Math::XYZPoint& position,
		const ROOT::Math::XYZVector& box) {

		auto intersect = LiangBarskyIntersectionDistances(direction, position, box);

		// The intersection is a point P + t * D. Return closest impact point if positive (i.e. in direction of the motion)
		if(intersect) {
		auto [t0, t1] = intersect.value();
		if(t0 > 0 && t1 > 0) {
		return (position + std::min(t0, t1) * direction);
		} else if(t0 > 0) {