Change swirl_rays line integration to integrate over the actual cell-wise constant solution.
Apply line tracing, to obtain all cells in the patch, that contribute to the integral.
Add untrustworthy-varibale to flcaw2d_rays_t routines to mark rays with unreliable integration results.
Adapt integration to allow axis-parallel (and almost axis-parallel) rays. If they are too close to a parallel patch face,
they will be marked as untrustworthy.
Change swirl_rays line integration to integrate over the actual cell-wise constant solution. Apply line tracing, to obtain all cells in the patch, that contribute to the integral. Add untrustworthy-varibale to flcaw2d_rays_t routines to mark rays with unreliable integration results. Adapt integration to allow axis-parallel (and almost axis-parallel) rays. If they are too close to a parallel patch face, they will be marked as untrustworthy.