Supply normals for edge hits (#7039)

* Pass out normals for edge hits

* Remove now-obsolete comments

* Also add third instance of disabled particle normal

Author: BMagnu

code/model/modelcollide.cpp

@@ -323,6 +323,7 @@ static void mc_check_sphereline_face( int nv, vec3d ** verts, vec3d * plane_pnt,
 				// This is closer than best so far
 				Mc->hit_dist = sphere_time;
 				Mc->hit_point = hit_point;
+				Mc->hit_normal = *plane_norm;
 				Mc->hit_submodel = Mc_submodel;
 				Mc->edge_hit = true;
 

code/weapon/beam.cpp

@@ -3962,18 +3962,15 @@ void beam_handle_collisions(beam *b)
 			if (wi->flash_impact_weapon_expl_effect.isValid()) {
 				auto particleSource = particle::ParticleManager::get()->createSource(wi->flash_impact_weapon_expl_effect);
 				particleSource->setHost(beam_hit_make_effect_host(b, &Objects[target], b->f_collisions[idx].cinfo.hit_submodel, &b->f_collisions[idx].cinfo.hit_point_world, &b->f_collisions[idx].cinfo.hit_point));
-// TODO: Commenting out until the collision code can be enhanced to return a valid normal when a beam collides with an edge.
-// (This can happen when a slash beam moves off the edge of a model; edge_hit will be true and hit_normal will be 0,0,0.)
-//				particleSource->setNormal(worldNormal);
+				particleSource->setNormal(worldNormal);
 				particleSource->setTriggerRadius(width);
 				particleSource->finishCreation();
 			}
 
 			if(do_expl){
 				auto particleSource = particle::ParticleManager::get()->createSource(wi->impact_weapon_expl_effect);
 				particleSource->setHost(beam_hit_make_effect_host(b, &Objects[target], b->f_collisions[idx].cinfo.hit_submodel, &b->f_collisions[idx].cinfo.hit_point_world, &b->f_collisions[idx].cinfo.hit_point));
-// TODO: see comment above
-//				particleSource->setNormal(worldNormal);
+				particleSource->setNormal(worldNormal);
 				particleSource->setTriggerRadius(width);
 				particleSource->finishCreation();
 			}
@@ -4029,8 +4026,7 @@ void beam_handle_collisions(beam *b)
 						auto particleSource = particle::ParticleManager::get()->createSource(wi->piercing_impact_effect);
 
 						particleSource->setHost(beam_hit_make_effect_host(b, &Objects[target], b->f_collisions[idx].cinfo.hit_submodel, &b->f_collisions[idx].cinfo.hit_point_world, &b->f_collisions[idx].cinfo.hit_point));
-// TODO: see comment above
-//						particleSource->setNormal(worldNormal);
+						particleSource->setNormal(worldNormal);
 						particleSource->setTriggerRadius(width);
 						particleSource->finishCreation();
 					}