diff options
| -rw-r--r-- | face_beam_interaction.m | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/face_beam_interaction.m b/face_beam_interaction.m index 4294c11..f7fbb2b 100644 --- a/face_beam_interaction.m +++ b/face_beam_interaction.m @@ -62,10 +62,16 @@ function [is_face_hit, hit_position, hit_distance, new_beams] = face_beam_inter % beam coming from the left n1=face.n_left; n2=face.n_right; + % this means that notmal and beam k vector point to the same half plane + % relative to the face + are_nf_and_k_in_the_same_plane=true; else % beam coming from the right n1=face.n_right; n2=face.n_left; + % this means that notmal and beam k vector point to the different half plane + % relative to the face + are_nf_and_k_in_the_same_plane=false; end % normal vector to the face, looks to the left of it @@ -75,14 +81,31 @@ function [is_face_hit, hit_position, hit_distance, new_beams] = face_beam_inter sin_theta_i = - ( k(1)*nf(2)-k(2)*nf(1) ) / (norm(k)*norm(nf)); % positive angle to the right from normal before incidence to the face theta_i = atan2(sin_theta_i, cos_theta_i); + + % we need to make sure that angle of incidence belong to [-pi/2,pi/2] interval + if( theta_i > pi/2) + theta_i=pi-theta_i; + end + if( theta_i < -pi/2) + theta_i=-pi+theta_i; + end - % reflected beam direction + % angle of the normal with respect to horizon theta_normal = atan2(nf(2), nf(1)); - theta_reflected = theta_normal + pi - theta_i; + + % reflected beam direction + if (are_nf_and_k_in_the_same_plane) + theta_reflected = theta_normal - theta_i + pi; + else + theta_reflected = theta_normal + theta_i; + end + beam_reflected.origin = hit_position; beam_reflected.k = [cos(theta_reflected), sin(theta_reflected)]; beam_reflected.face=closest_face_index; + reflectivity = .1; + beam_reflected.intensity = beam.intensity * reflectivity; new_beams{1} = beam_reflected; @@ -94,11 +117,17 @@ function [is_face_hit, hit_position, hit_distance, new_beams] = face_beam_inter else % beam refracts theta_refracted_rel2normal = asin( sin_theta_refracted_rel2normal ); - theta_refracted = theta_normal + theta_refracted_rel2normal; + if (are_nf_and_k_in_the_same_plane) + theta_refracted = theta_normal + theta_refracted_rel2normal; + else + theta_refracted = theta_normal - theta_refracted_rel2normal + pi; + end beam_refracted.origin = hit_position; beam_refracted.k = [cos(theta_refracted), sin(theta_refracted)]; beam_refracted.face=closest_face_index; + transmission = .1; + beam_refracted.intensity = beam.intensity * transmission; new_beams{2} = beam_refracted; end end |