Spline IK: support changing individual bone length via Y scaling.

Previously Spline IK provided only two choices: either scale the
length of the bone chain to fit the length of the curve, or don't
scale the bone in the Y dimension at all (ignoring effects of
actually fitting to the curve due to curvature and curve object
scale).

This patch adds a new option to use the pre-IK Y scale of the
bones to adjust their length when fitted to the curve, allowing
individual posing control over the length of the segments.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D4687

1 files changed, 17 insertions, 0 deletions

diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 41b1627e873..528bfd2360f 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -3140,6 +3140,23 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
 	}
 
 	{
+		if (!DNA_struct_elem_find(fd->filesdna, "bSplineIKConstraint", "short", "yScaleMode")) {
+			for (Object *ob = bmain->objects.first; ob; ob = ob->id.next) {
+				if (ob->pose) {
+					for (bPoseChannel *pchan = ob->pose->chanbase.first; pchan; pchan = pchan->next) {
+						for (bConstraint *con = pchan->constraints.first; con; con = con->next) {
+							if (con->type == CONSTRAINT_TYPE_SPLINEIK) {
+								bSplineIKConstraint *data = (bSplineIKConstraint *)con->data;
+								if ((data->flag & CONSTRAINT_SPLINEIK_SCALE_LIMITED) == 0) {
+									data->yScaleMode = CONSTRAINT_SPLINEIK_YS_FIT_CURVE;
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+
 		/* Versioning code until next subversion bump goes here. */
 	}
 }