New pchan to pose matrices computes. Fixes [#27898] Bone snap to cursor fails and [#29461] Selection-to-Cursor works strange with bones with TrackTo constraint. Also fixes some inconsistant behavior of no Inherit Rotation/Scale options.

WARNING: This commits modifies how translated unconnected child bones with *no Inherit Rotation option* are positionned. This means that if you open a posed/animated armature using such (corner-case) setup, you'll have to adjust manually the locations of such bones: now, disabling Inherit Rotation/Scale will no more move the bone, only affecting its rotation/scale.

Many thanks to Bassam Kurdali (slikdigit) for his advices and tests of the patch!

-----

Dev notes : the pchan_to_pose_mat() func was added to BKE_armature.h, which computes two matrices to get the pose transformations (pchan) of the bone directly in pose (i.e. armature object) space. The first matrix is the rotation/scaling parts, the second one is for location.

That new function is used by (hence deduplicating and simplifying their code):
* The pose evaluation code (where_is_pose_bone()).
* The interactive transformation code (add_pose_transdata(), in transform_conversion.c).
* The snap to cursor/grid code (through armature_loc_pose_to_bone()/armature_mat_pose_to_bone()).

1 files changed, 40 insertions, 8 deletions

diff --git a/source/blender/editors/transform/transform_conversions.c b/source/blender/editors/transform/transform_conversions.c
index 44dc909314a..b060c04de4e 100644
--- a/source/blender/editors/transform/transform_conversions.c
+++ b/source/blender/editors/transform/transform_conversions.c
@@ -515,7 +515,7 @@ static short apply_targetless_ik(Object *ob)
 static void add_pose_transdata(TransInfo *t, bPoseChannel *pchan, Object *ob, TransData *td)
 {
 	Bone *bone= pchan->bone;
-	float pmat[3][3], omat[3][3], bmat[3][3];
+	float pmat[3][3], omat[3][3];
 	float cmat[3][3], tmat[3][3];
 	float vec[3];
 
@@ -569,39 +569,71 @@ static void add_pose_transdata(TransInfo *t, bPoseChannel *pchan, Object *ob, Tr
 		copy_qt_qt(td->ext->iquat, pchan->quat);
 	}
 	td->ext->rotOrder= pchan->rotmode;
-	
+
 
 	/* proper way to get parent transform + own transform + constraints transform */
 	copy_m3_m4(omat, ob->obmat);
 
+	/* New code, using "generic" pchan_to_pose_mat(). */
+	{
+		float rotscale_mat[4][4], loc_mat[4][4];
+
+		pchan_to_pose_mat(pchan, rotscale_mat, loc_mat);
+		if (t->mode == TFM_TRANSLATION)
+			copy_m3_m4(pmat, loc_mat);
+		else
+			copy_m3_m4(pmat, rotscale_mat);
+
+		if (constraints_list_needinv(t, &pchan->constraints)) {
+			copy_m3_m4(tmat, pchan->constinv);
+			invert_m3_m3(cmat, tmat);
+			mul_serie_m3(td->mtx, pmat, omat, cmat, NULL,NULL,NULL,NULL,NULL);
+		}
+		else
+			mul_serie_m3(td->mtx, pmat, omat, NULL, NULL,NULL,NULL,NULL,NULL);
+	}
+
+	/* XXX Old code. Will remove it later. */
+#if 0
 	if (ELEM(t->mode, TFM_TRANSLATION, TFM_RESIZE) && (pchan->bone->flag & BONE_NO_LOCAL_LOCATION))
 		unit_m3(bmat);
 	else
 		copy_m3_m3(bmat, pchan->bone->bone_mat);
 
 	if (pchan->parent) {
-		if(pchan->bone->flag & BONE_HINGE)
+		if(pchan->bone->flag & BONE_HINGE) {
 			copy_m3_m4(pmat, pchan->parent->bone->arm_mat);
-		else
+			if(!(pchan->bone->flag & BONE_NO_SCALE)) {
+				float tsize[3], tsmat[3][3];
+				mat4_to_size(tsize, pchan->parent->pose_mat);
+				size_to_mat3(tsmat, tsize);
+				mul_m3_m3m3(pmat, tsmat, pmat);
+			}
+		}
+		else {
 			copy_m3_m4(pmat, pchan->parent->pose_mat);
+			if(pchan->bone->flag & BONE_NO_SCALE)
+				normalize_m3(pmat);
+		}
 
 		if (constraints_list_needinv(t, &pchan->constraints)) {
 			copy_m3_m4(tmat, pchan->constinv);
 			invert_m3_m3(cmat, tmat);
-			mul_serie_m3(td->mtx, bmat, pmat, omat, cmat, NULL,NULL,NULL,NULL);    // dang mulserie swaps args
+			mul_serie_m3(td->mtx, bmat, pmat, omat, cmat, NULL,NULL,NULL,NULL);
 		}
 		else
-			mul_serie_m3(td->mtx, bmat, pmat, omat, NULL,NULL,NULL,NULL,NULL);    // dang mulserie swaps args
+			mul_serie_m3(td->mtx, bmat, pmat, omat, NULL,NULL,NULL,NULL,NULL);
 	}
 	else {
 		if (constraints_list_needinv(t, &pchan->constraints)) {
 			copy_m3_m4(tmat, pchan->constinv);
 			invert_m3_m3(cmat, tmat);
-			mul_serie_m3(td->mtx, bmat, omat, cmat, NULL,NULL,NULL,NULL,NULL);    // dang mulserie swaps args
+			mul_serie_m3(td->mtx, bmat, omat, cmat, NULL,NULL,NULL,NULL,NULL);
 		}
 		else
-			mul_m3_m3m3(td->mtx, omat, bmat);  // Mat3MulMat3 has swapped args!
+			mul_m3_m3m3(td->mtx, omat, bmat);
 	}
+# endif
 
 	invert_m3_m3(td->smtx, td->mtx);