Fix T32214: Wireframe edge select fails with verts behind the view

This resolves a long standing bug in edge selection
(picking, circle, box & lasso).

Now when one of the edges vertices fails to project into screen space,
the edge is clipped by the viewport to calculate an on-screen location
that can be used instead.

This isn't default as it may be important for the on the screen location
not to be clipped by the viewport.

1 files changed, 6 insertions, 3 deletions

diff --git a/source/blender/editors/mesh/editmesh_select.c b/source/blender/editors/mesh/editmesh_select.c
index 6e5dd47e282..b21645a1a5d 100644
--- a/source/blender/editors/mesh/editmesh_select.c
+++ b/source/blender/editors/mesh/editmesh_select.c
@@ -547,8 +547,10 @@ BMEdge *EDBM_edge_find_nearest_ex(ViewContext *vc,
 
       ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);
 
-      mesh_foreachScreenEdge(
-          vc, find_nearest_edge_center__doZBuf, &data, V3D_PROJ_TEST_CLIP_DEFAULT);
+      mesh_foreachScreenEdge(vc,
+                             find_nearest_edge_center__doZBuf,
+                             &data,
+                             V3D_PROJ_TEST_CLIP_DEFAULT | V3D_PROJ_TEST_CLIP_CONTENT_DEFAULT);
 
       *r_dist_center_px_manhattan = data.dist;
     }
@@ -601,7 +603,8 @@ BMEdge *EDBM_edge_find_nearest_ex(ViewContext *vc,
         *dist_px_manhattan_p;
 
     ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);
-    mesh_foreachScreenEdge(vc, find_nearest_edge__doClosest, &data, clip_flag);
+    mesh_foreachScreenEdge(
+        vc, find_nearest_edge__doClosest, &data, clip_flag | V3D_PROJ_TEST_CLIP_CONTENT_DEFAULT);
 
     hit = (data.use_cycle && data.hit_cycle.edge) ? &data.hit_cycle : &data.hit;