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!

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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, 5 insertions, 10 deletions

diff --git a/source/blender/editors/space_view3d/view3d_snap.c b/source/blender/editors/space_view3d/view3d_snap.c
index 6bc1b3acce6..3665b0b13c3 100644
--- a/source/blender/editors/space_view3d/view3d_snap.c
+++ b/source/blender/editors/space_view3d/view3d_snap.c
@@ -505,7 +505,6 @@ static int snap_sel_to_grid(bContext *C, wmOperator *UNUSED(op))
 						if(pchan->bone->layer & arm->layer) {
 							if((pchan->bone->flag & BONE_CONNECTED)==0) {
 								float nLoc[3];
-								float inv_restmat[4][4];
 								
 								/* get nearest grid point to snap to */
 								copy_v3_v3(nLoc, pchan->pose_mat[3]);
@@ -517,9 +516,8 @@ static int snap_sel_to_grid(bContext *C, wmOperator *UNUSED(op))
 								/* Back in object space... */
 								mul_m4_v3(ob->imat, vec);
 								
-								/* get location of grid point in *rest* bone-space */
-								invert_m4_m4(inv_restmat, pchan->bone->arm_mat);
-								mul_m4_v3(inv_restmat, vec);
+								/* Get location of grid point in pose space. */
+								armature_loc_pose_to_bone(pchan, vec, vec);
 								
 								/* adjust location */
 								if ((pchan->protectflag & OB_LOCK_LOCX)==0)
@@ -642,12 +640,9 @@ static int snap_sel_to_curs(bContext *C, wmOperator *UNUSED(op))
 					if(pchan->bone->flag & BONE_SELECTED) {
 						if(pchan->bone->layer & arm->layer) {
 							if((pchan->bone->flag & BONE_CONNECTED)==0) {
-								float inv_restmat[4][4];
-								
-								/* get location of cursor in *rest* bone-space */
-								invert_m4_m4(inv_restmat, pchan->bone->arm_mat);
-								mul_m4_v3(inv_restmat, vec);
-								
+								/* Get position in pchan (pose) space. */
+								armature_loc_pose_to_bone(pchan, vec, vec);
+
 								/* copy new position */
 								if ((pchan->protectflag & OB_LOCK_LOCX)==0)
 									pchan->loc[0]= vec[0];