Armature pose evaluation: more factorization of code.

Now constraints' space conversion code also uses generic armature_mat_(pose_to_bone/bone_to_pose). Previous own function (constraint_pchan_diff_mat) was somewhat inconsistent too with Hinge/NoScale/LocalLocation options...
As with previous similar changes, this might break some old rigs, in very specific cases (when constraint-evaluating an hinge/noscale/local_location bone in local space).

In the same part of code, removed unnecessary matrices copying, mult_m4_m4m4 can take the same matrix as input and output, nowadays...

Also found a bug-generator weakness in those armature_mat_ functions (if both input and output mat where the same, result was wrong, now systematically copying input mat, as done in LIB's matrix funcs).

Finally, factorized offset bone matrix generation into its own small function too, as it is used in two different places in armature.c (pchan_to_pose_mat itself, and restpose's where_is_armature_bone).

Note: I think all parts of blender's code related to that topic have now been tackled, but yet have to check BGE, it’s probably using that stuff too, one way or the other...

1 files changed, 36 insertions, 26 deletions

diff --git a/source/blender/blenkernel/intern/armature.c b/source/blender/blenkernel/intern/armature.c
index 922ac3fd3a4..36646c85dc1 100644
--- a/source/blender/blenkernel/intern/armature.c
+++ b/source/blender/blenkernel/intern/armature.c
@@ -1129,6 +1129,24 @@ void armature_loc_world_to_pose(Object *ob, float *inloc, float *outloc)
 	copy_v3_v3(outloc, nLocMat[3]);
 }
 
+/* Simple helper, computes the offset bone matrix.
+ *     offs_bone = yoffs(b-1) + root(b) + bonemat(b).
+ * Not exported, as it is only used in this file currently... */
+static void get_offset_bone_mat(Bone *bone, float offs_bone[][4])
+{
+	if (!bone->parent)
+		return;
+
+	/* Bone transform itself. */
+	copy_m4_m3(offs_bone, bone->bone_mat);
+
+	/* The bone's root offset (is in the parent's coordinate system). */
+	copy_v3_v3(offs_bone[3], bone->head);
+
+	/* Get the length translation of parent (length along y axis). */
+	offs_bone[3][1] += bone->parent->length;
+}
+
 /* Construct the matrices (rot/scale and loc) to apply the PoseChannels into the armature (object) space.
  * I.e. (roughly) the "pose_mat(b-1) * yoffs(b-1) * d_root(b) * bone_mat(b)" in the
  *     pose_mat(b)= pose_mat(b-1) * yoffs(b-1) * d_root(b) * bone_mat(b) * chan_mat(b)
@@ -1157,16 +1175,9 @@ void pchan_to_pose_mat(bPoseChannel *pchan, float rotscale_mat[][4], float loc_m
 	parchan = pchan->parent;
 
 	if (parchan) {
-		float offs_bone[4][4]; /* yoffs(b-1) + root(b) + bonemat(b). */
-
-		/* Bone transform itself. */
-		copy_m4_m3(offs_bone, bone->bone_mat);
-
-		/* The bone's root offset (is in the parent's coordinate system). */
-		copy_v3_v3(offs_bone[3], bone->head);
-
-		/* Get the length translation of parent (length along y axis). */
-		offs_bone[3][1] += parbone->length;
+		float offs_bone[4][4];
+		/* yoffs(b-1) + root(b) + bonemat(b). */
+		get_offset_bone_mat(bone, offs_bone);
 
 		/* Compose the rotscale matrix for this bone. */
 		if ((bone->flag & BONE_HINGE) && (bone->flag & BONE_NO_SCALE)) {
@@ -1297,25 +1308,31 @@ void pchan_to_pose_mat(bPoseChannel *pchan, float rotscale_mat[][4], float loc_m
  *       pose-channel into its local space (i.e. 'visual'-keyframing) */
 void armature_mat_pose_to_bone(bPoseChannel *pchan, float inmat[][4], float outmat[][4])
 {
-	float rotscale_mat[4][4], loc_mat[4][4];
+	float rotscale_mat[4][4], loc_mat[4][4], inmat_[4][4];
+
+	/* Security, this allows to call with inmat == outmat! */
+	copy_m4_m4(inmat_, inmat);
 
 	pchan_to_pose_mat(pchan, rotscale_mat, loc_mat);
 	invert_m4(rotscale_mat);
 	invert_m4(loc_mat);
 
-	mult_m4_m4m4(outmat, rotscale_mat, inmat);
-	mul_v3_m4v3(outmat[3], loc_mat, inmat[3]);
+	mult_m4_m4m4(outmat, rotscale_mat, inmat_);
+	mul_v3_m4v3(outmat[3], loc_mat, inmat_[3]);
 }
 
 /* Convert Bone-Space Matrix to Pose-Space Matrix. */
 void armature_mat_bone_to_pose(bPoseChannel *pchan, float inmat[][4], float outmat[][4])
 {
-	float rotscale_mat[4][4], loc_mat[4][4];
+	float rotscale_mat[4][4], loc_mat[4][4], inmat_[4][4];
+
+	/* Security, this allows to call with inmat == outmat! */
+	copy_m4_m4(inmat_, inmat);
 
 	pchan_to_pose_mat(pchan, rotscale_mat, loc_mat);
 
-	mult_m4_m4m4(outmat, rotscale_mat, inmat);
-	mul_v3_m4v3(outmat[3], loc_mat, inmat[3]);
+	mult_m4_m4m4(outmat, rotscale_mat, inmat_);
+	mul_v3_m4v3(outmat[3], loc_mat, inmat_[3]);
 }
 
 /* Convert Pose-Space Location to Bone-Space Location
@@ -1546,16 +1563,9 @@ void where_is_armature_bone(Bone *bone, Bone *prevbone)
 	}
 
 	if (prevbone) {
-		float offs_bone[4][4];  /* yoffs(b-1) + root(b) + bonemat(b) */
-
-		/* bone transform itself */
-		copy_m4_m3(offs_bone, bone->bone_mat);
-
-		/* The bone's root offset (is in the parent's coordinate system) */
-		copy_v3_v3(offs_bone[3], bone->head);
-
-		/* Get the length translation of parent (length along y axis) */
-		offs_bone[3][1] += prevbone->length;
+		float offs_bone[4][4];
+		/* yoffs(b-1) + root(b) + bonemat(b) */
+		get_offset_bone_mat(bone, offs_bone);
 
 		/* Compose the matrix for this bone  */
 		mult_m4_m4m4(bone->arm_mat, prevbone->arm_mat, offs_bone);