Armature: add automatic B-Bone Scale toggles.

Currently B-Bone scaling can only be controlled via their
properties, thus requiring up to 8 drivers per joint between
B-Bones to transfer scaling factors from the handle bone.

A Scale Easing option is added to multiply the easing value
by the Y scale channels to synchronize them - this produces a
natural scaling effect where both the shape of the curve and
the scale is affected.

In addition, four toggles are added for each handle, which
multiply each of the X, Y, Z and Ease values by the matching
Local Scale channel of the handle bone, thus replacing trivial
drivers. The Scale Easing option has no effect on this process
since it's easy to just enable both Length and Ease buttons.

Differential Revision: https://developer.blender.org/D9870

1 files changed, 59 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/armature.c b/source/blender/blenkernel/intern/armature.c
index 93ad6f37233..2cd089545e8 100644
--- a/source/blender/blenkernel/intern/armature.c
+++ b/source/blender/blenkernel/intern/armature.c
@@ -959,7 +959,7 @@ void BKE_pchan_bbone_spline_params_get(struct bPoseChannel *pchan,
 {
   bPoseChannel *next, *prev;
   Bone *bone = pchan->bone;
-  float imat[4][4], posemat[4][4];
+  float imat[4][4], posemat[4][4], tmpmat[4][4];
   float delta[3];
 
   memset(param, 0, sizeof(*param));
@@ -996,6 +996,11 @@ void BKE_pchan_bbone_spline_params_get(struct bPoseChannel *pchan,
     invert_m4_m4(imat, pchan->pose_mat);
   }
 
+  float prev_scale[3], next_scale[3];
+
+  copy_v3_fl(prev_scale, 1.0f);
+  copy_v3_fl(next_scale, 1.0f);
+
   if (prev) {
     float h1[3];
     bool done = false;
@@ -1041,6 +1046,12 @@ void BKE_pchan_bbone_spline_params_get(struct bPoseChannel *pchan,
     if (!param->prev_bbone) {
       /* Find the previous roll to interpolate. */
       mul_m4_m4m4(param->prev_mat, imat, rest ? prev->bone->arm_mat : prev->pose_mat);
+
+      /* Retrieve the local scale of the bone if necessary. */
+      if ((bone->bbone_prev_flag & BBONE_HANDLE_SCALE_ANY) && !rest) {
+        BKE_armature_mat_pose_to_bone(prev, prev->pose_mat, tmpmat);
+        mat4_to_size(prev_scale, tmpmat);
+      }
     }
   }
 
@@ -1088,6 +1099,12 @@ void BKE_pchan_bbone_spline_params_get(struct bPoseChannel *pchan,
 
     /* Find the next roll to interpolate as well. */
     mul_m4_m4m4(param->next_mat, imat, rest ? next->bone->arm_mat : next->pose_mat);
+
+    /* Retrieve the local scale of the bone if necessary. */
+    if ((bone->bbone_next_flag & BBONE_HANDLE_SCALE_ANY) && !rest) {
+      BKE_armature_mat_pose_to_bone(next, next->pose_mat, tmpmat);
+      mat4_to_size(next_scale, tmpmat);
+    }
   }
 
   /* Add effects from bbone properties over the top
@@ -1137,6 +1154,47 @@ void BKE_pchan_bbone_spline_params_get(struct bPoseChannel *pchan,
 
     param->curve_out_x = bone->curve_out_x + (!rest ? pchan->curve_out_x : 0.0f);
     param->curve_out_z = bone->curve_out_z + (!rest ? pchan->curve_out_z : 0.0f);
+
+    if (bone->bbone_flag & BBONE_SCALE_EASING) {
+      param->ease1 *= param->scale_in[1];
+      param->curve_in_x *= param->scale_in[1];
+      param->curve_in_z *= param->scale_in[1];
+
+      param->ease2 *= param->scale_out[1];
+      param->curve_out_x *= param->scale_out[1];
+      param->curve_out_z *= param->scale_out[1];
+    }
+
+    /* Custom handle scale. */
+    if (bone->bbone_prev_flag & BBONE_HANDLE_SCALE_X) {
+      param->scale_in[0] *= prev_scale[0];
+    }
+    if (bone->bbone_prev_flag & BBONE_HANDLE_SCALE_Y) {
+      param->scale_in[1] *= prev_scale[1];
+    }
+    if (bone->bbone_prev_flag & BBONE_HANDLE_SCALE_Z) {
+      param->scale_in[2] *= prev_scale[2];
+    }
+    if (bone->bbone_prev_flag & BBONE_HANDLE_SCALE_EASE) {
+      param->ease1 *= prev_scale[1];
+      param->curve_in_x *= prev_scale[1];
+      param->curve_in_z *= prev_scale[1];
+    }
+
+    if (bone->bbone_next_flag & BBONE_HANDLE_SCALE_X) {
+      param->scale_out[0] *= next_scale[0];
+    }
+    if (bone->bbone_next_flag & BBONE_HANDLE_SCALE_Y) {
+      param->scale_out[1] *= next_scale[1];
+    }
+    if (bone->bbone_next_flag & BBONE_HANDLE_SCALE_Z) {
+      param->scale_out[2] *= next_scale[2];
+    }
+    if (bone->bbone_next_flag & BBONE_HANDLE_SCALE_EASE) {
+      param->ease2 *= next_scale[1];
+      param->curve_out_x *= next_scale[1];
+      param->curve_out_z *= next_scale[1];
+    }
   }
 }