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Fix T51971: IK non-uniform scale regression. 

This is a different fix for the issue from D2088, preserving backwards compatibility
for IK stretching. The main problem with this patch is that this new behavior has
been there for a year, so it may break rigs created since then which rely on the new
IK stretch behavior.

Test file for various cases:
https://developer.blender.org/diffusion/BL/browse/trunk/lib/tests/animation/IK.blend

Reviewers: campbellbarton

Subscribers: maverick, pkrime

Differential Revision: https://developer.blender.org/D2743
This commit is contained in:
Brecht Van Lommel 2017-07-05 23:15:12 +02:00
parent 9feeb14e91
commit f05f2f0336
Notes: blender-bot 2023-02-14 06:49:53 +01:00 
Referenced by issue #51971, IK with non uniform scale broke the animation tools
1 changed files with 24 additions and 26 deletions
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50
source/blender/ikplugin/intern/iksolver_plugin.c
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@ -217,9 +217,27 @@ static void where_is_ik_bone(bPoseChannel *pchan, float ik_mat[3][3]) // nr =
copy_m4_m3(ikmat, ik_mat);
if (pchan->parent)
mul_m4_series(pchan->pose_mat, pchan->parent->pose_mat, pchan->chan_mat, ikmat);
mul_m4_m4m4(pchan->pose_mat, pchan->parent->pose_mat, pchan->chan_mat);
else
mul_m4_m4m4(pchan->pose_mat, pchan->chan_mat, ikmat);
copy_m4_m4(pchan->pose_mat, pchan->chan_mat);
#ifdef USE_NONUNIFORM_SCALE
/* apply IK mat, but as if the bones have uniform scale since the IK solver
* is not aware of non-uniform scale */
float scale[3];
mat4_to_size(scale, pchan->pose_mat);
normalize_v3_length(pchan->pose_mat[0], scale[1]);
normalize_v3_length(pchan->pose_mat[2], scale[1]);
#endif
mul_m4_m4m4(pchan->pose_mat, pchan->pose_mat, ikmat);
#ifdef USE_NONUNIFORM_SCALE
float ik_scale[3];
mat3_to_size(ik_scale, ik_mat);
normalize_v3_length(pchan->pose_mat[0], scale[0] * ik_scale[0]);
normalize_v3_length(pchan->pose_mat[2], scale[2] * ik_scale[2]);
#endif
/* calculate head */
copy_v3_v3(pchan->pose_head, pchan->pose_mat[3]);
@ -308,6 +326,10 @@ static void execute_posetree(struct Scene *scene, Object *ob, PoseTree *tree)
/* change length based on bone size */
length = bone->length * len_v3(R_bonemat[1]);
/* basis must be pure rotation */
normalize_m3(R_bonemat);
normalize_m3(R_parmat);
/* compute rest basis and its inverse */
copy_m3_m3(rest_basis, bone->bone_mat);
transpose_m3_m3(irest_basis, bone->bone_mat);
@ -317,11 +339,7 @@ static void execute_posetree(struct Scene *scene, Object *ob, PoseTree *tree)
mul_m3_m3m3(full_basis, iR_parmat, R_bonemat);
mul_m3_m3m3(basis, irest_basis, full_basis);
/* basis must be pure rotation */
normalize_m3(basis);
/* transform offset into local bone space */
normalize_m3(iR_parmat);
mul_m3_v3(iR_parmat, start);
IK_SetTransform(seg, start, rest_basis, basis, length);
@ -545,18 +563,6 @@ void iksolver_execute_tree(struct Scene *scene, Object *ob, bPoseChannel *pchan
tree->pchan[a]->flag |= POSE_CHAIN;
}
#ifdef USE_NONUNIFORM_SCALE
float (*pchan_scale_data)[3] = MEM_mallocN(sizeof(float[3]) * tree->totchannel, __func__);
for (a = 0; a < tree->totchannel; a++) {
mat4_to_size(pchan_scale_data[a], tree->pchan[a]->pose_mat);
/* make uniform at y scale since this controls the length */
normalize_v3_length(tree->pchan[a]->pose_mat[0], pchan_scale_data[a][1]);
normalize_v3_length(tree->pchan[a]->pose_mat[2], pchan_scale_data[a][1]);
}
#endif
/* 5. execute the IK solver */
execute_posetree(scene, ob, tree);
@ -571,14 +577,6 @@ void iksolver_execute_tree(struct Scene *scene, Object *ob, bPoseChannel *pchan
where_is_ik_bone(tree->pchan[a], tree->basis_change[a]);
}
#ifdef USE_NONUNIFORM_SCALE
for (a = 0; a < tree->totchannel; a++) {
normalize_v3_length(tree->pchan[a]->pose_mat[0], pchan_scale_data[a][0]);
normalize_v3_length(tree->pchan[a]->pose_mat[2], pchan_scale_data[a][2]);
}
MEM_freeN(pchan_scale_data);
#endif
/* 7. and free */
BLI_remlink(&pchan_root->iktree, tree);
free_posetree(tree);