Implement additional modes for Shrinkwrap to a surface.

In addition to the original map to surface and Keep Above Surface,
add modes that only affect vertices that are inside or outside
the object. This is inspired by the Limit Distance constraint,
and can be useful for crude collision detection in rigs.

The inside/outside test works based on face normals and may not be
completely reliable near 90 degree or sharper angles in the target.

Reviewers: campbellbarton, mont29

Differential Revision: https://developer.blender.org/D3717

1 files changed, 18 insertions, 6 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 3ea2f4e0ee4..b1a7c98dc9c 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -3456,7 +3456,6 @@ static void shrinkwrap_get_tarmat(struct Depsgraph *depsgraph, bConstraint *con,
 				case MOD_SHRINKWRAP_NEAREST_VERTEX:
 				{
 					BVHTreeNearest nearest;
-					float dist;
 
 					nearest.index = -1;
 					nearest.dist_sq = FLT_MAX;
@@ -3475,10 +3474,22 @@ static void shrinkwrap_get_tarmat(struct Depsgraph *depsgraph, bConstraint *con,
 
 					BLI_bvhtree_find_nearest(treeData.tree, co, &nearest, treeData.nearest_callback, &treeData);
 
-					dist = len_v3v3(co, nearest.co);
-					if (dist != 0.0f) {
-						interp_v3_v3v3(co, co, nearest.co, (dist - scon->dist) / dist);   /* linear interpolation */
+					if (nearest.index < 0) {
+						fail = true;
+						break;
 					}
+
+					if (scon->shrinkType == MOD_SHRINKWRAP_NEAREST_SURFACE) {
+						BKE_shrinkwrap_snap_point_to_surface(scon->shrinkMode, nearest.co, nearest.no, scon->dist, co, co);
+					}
+					else {
+						const float dist = len_v3v3(co, nearest.co);
+
+						if (dist != 0.0f) {
+							interp_v3_v3v3(co, co, nearest.co, (dist - scon->dist) / dist);   /* linear interpolation */
+						}
+					}
+
 					BLI_space_transform_invert(&transform, co);
 					break;
 				}
@@ -3522,13 +3533,14 @@ static void shrinkwrap_get_tarmat(struct Depsgraph *depsgraph, bConstraint *con,
 						break;
 					}
 
-					if (BKE_shrinkwrap_project_normal(0, co, no, scon->dist, &transform, treeData.tree,
+					if (BKE_shrinkwrap_project_normal(0, co, no, 0.0f, &transform, treeData.tree,
 					                                  &hit, treeData.raycast_callback, &treeData) == false)
 					{
 						fail = true;
 						break;
 					}
-					copy_v3_v3(co, hit.co);
+
+					BKE_shrinkwrap_snap_point_to_surface(scon->shrinkMode, hit.co, hit.no, scon->dist, co, co);
 					break;
 				}
 			}