Fix T40991, mirrored armatures not restored properly when cancelling.

Issue here is that we force mirroring even if original armature is not
mirrored.

We could be smart and store only unselected mirrored bones here (since
those will get restored from transdata), however not all properties were
getting stored and restored; rolling bones still suffered from the bug
for instance.

To fix this we need to restore all properties that armature mirroring
overrides. Transdata obviously does not offer a lot of space here, so I
used TransInfo->customdata to store an array of initial parameters of
the mirrored bones.

3 files changed, 81 insertions, 6 deletions

diff --git a/source/blender/editors/transform/transform.h b/source/blender/editors/transform/transform.h
index f5a1812750e..0bccf177128 100644
--- a/source/blender/editors/transform/transform.h
+++ b/source/blender/editors/transform/transform.h
@@ -61,6 +61,7 @@ struct wmEvent;
 struct wmTimer;
 struct ARegion;
 struct ReportList;
+struct EditBone;
 
 /* transinfo->redraw */
 typedef enum {
@@ -251,6 +252,17 @@ typedef struct VertSlideData {
 	int curr_sv_index;
 } VertSlideData;
 
+typedef struct BoneInitData {
+	struct EditBone *bone;
+	float tail[3];
+	float rad_tail;
+	float roll;
+	float head[3];
+	float dist;
+	float xwidth;
+	float zwidth;
+} BoneInitData;
+
 typedef struct TransData {
 	float  dist;         /* Distance needed to affect element (for Proportionnal Editing)                  */
 	float  rdist;        /* Distance to the nearest element (for Proportionnal Editing)                    */
@@ -520,6 +532,7 @@ void flushTransNodes(TransInfo *t);
 void flushTransSeq(TransInfo *t);
 void flushTransTracking(TransInfo *t);
 void flushTransMasking(TransInfo *t);
+void restoreBones(TransInfo *t);
 
 /*********************** exported from transform_manipulator.c ********** */
 bool gimbal_axis(struct Object *ob, float gmat[3][3]); /* return 0 when no gimbal for selection */
diff --git a/source/blender/editors/transform/transform_conversions.c b/source/blender/editors/transform/transform_conversions.c
index 5d22b1130c0..9dfd3e568e5 100644
--- a/source/blender/editors/transform/transform_conversions.c
+++ b/source/blender/editors/transform/transform_conversions.c
@@ -1052,18 +1052,43 @@ static void createTransPose(TransInfo *t, Object *ob)
 	if (ik_on) transform_autoik_update(t, 0);
 }
 
-/* ********************* armature ************** */
+void restoreBones(TransInfo *t)
+{
+	BoneInitData *bid = t->customData;
+	EditBone *ebo;
+
+	while (bid->bone) {
+		ebo = bid->bone;
+		ebo->dist = bid->dist;
+		ebo->rad_tail = bid->rad_tail;
+		ebo->roll = bid->roll;
+		ebo->xwidth = bid->xwidth;
+		ebo->zwidth = bid->zwidth;
+		copy_v3_v3(ebo->head, bid->head);
+		copy_v3_v3(ebo->tail, bid->tail);
+
+		bid++;
+	}
+}
 
+
+/* ********************* armature ************** */
 static void createTransArmatureVerts(TransInfo *t)
 {
-	EditBone *ebo;
+	EditBone *ebo, *eboflip;
 	bArmature *arm = t->obedit->data;
 	ListBase *edbo = arm->edbo;
-	TransData *td;
+	TransData *td, *td_old;
 	float mtx[3][3], smtx[3][3], bonemat[3][3];
+	bool mirror = ((arm->flag & ARM_MIRROR_EDIT) != 0);
+	int total_mirrored = 0, i;
+	int oldtot;
+	BoneInitData *bid;
 	
 	t->total = 0;
 	for (ebo = edbo->first; ebo; ebo = ebo->next) {
+		oldtot = t->total;
+
 		if (EBONE_VISIBLE(arm, ebo) && !(ebo->flag & BONE_EDITMODE_LOCKED)) {
 			if (t->mode == TFM_BONESIZE) {
 				if (ebo->flag & BONE_SELECTED)
@@ -1080,6 +1105,12 @@ static void createTransArmatureVerts(TransInfo *t)
 					t->total++;
 			}
 		}
+
+		if (mirror && (oldtot < t->total)) {
+			eboflip = ED_armature_bone_get_mirrored(arm->edbo, ebo);
+			if (eboflip)
+				total_mirrored++;
+		}
 	}
 
 	if (!t->total) return;
@@ -1091,7 +1122,15 @@ static void createTransArmatureVerts(TransInfo *t)
 
 	td = t->data = MEM_callocN(t->total * sizeof(TransData), "TransEditBone");
 
+	if (mirror) {
+		t->customData = bid = MEM_mallocN((total_mirrored + 1) * sizeof(BoneInitData), "BoneInitData");
+		t->flag |= T_FREE_CUSTOMDATA;
+	}
+
+	i = 0;
+
 	for (ebo = edbo->first; ebo; ebo = ebo->next) {
+		td_old = td;
 		ebo->oldlength = ebo->length;   // length==0.0 on extrude, used for scaling radius of bone points
 
 		if (EBONE_VISIBLE(arm, ebo) && !(ebo->flag & BONE_EDITMODE_LOCKED)) {
@@ -1223,6 +1262,26 @@ static void createTransArmatureVerts(TransInfo *t)
 				}
 			}
 		}
+
+		if (mirror && (td_old != td)) {
+			eboflip = ED_armature_bone_get_mirrored(arm->edbo, ebo);
+			if (eboflip) {
+				bid[i].bone = eboflip;
+				bid[i].dist = eboflip->dist;
+				bid[i].rad_tail = eboflip->rad_tail;
+				bid[i].roll = eboflip->roll;
+				bid[i].xwidth = eboflip->xwidth;
+				bid[i].zwidth = eboflip->zwidth;
+				copy_v3_v3(bid[i].head, eboflip->head);
+				copy_v3_v3(bid[i].tail, eboflip->tail);
+				i++;
+			}
+		}
+	}
+
+	if (mirror && total_mirrored) {
+		/* trick to terminate iteration */
+		bid[total_mirrored].bone = NULL;
 	}
 }
 
diff --git a/source/blender/editors/transform/transform_generics.c b/source/blender/editors/transform/transform_generics.c
index 6eb88212714..15d1bb75d89 100644
--- a/source/blender/editors/transform/transform_generics.c
+++ b/source/blender/editors/transform/transform_generics.c
@@ -847,9 +847,12 @@ static void recalcData_objects(TransInfo *t)
 				}
 			}
 			
-			if (arm->flag & ARM_MIRROR_EDIT)
-				transform_armature_mirror_update(t->obedit);
-			
+			if (arm->flag & ARM_MIRROR_EDIT) {
+				if (t->state != TRANS_CANCEL)
+					transform_armature_mirror_update(t->obedit);
+				else
+					restoreBones(t);
+			}
 		}
 		else {
 			if (t->state != TRANS_CANCEL) {