Transformation Constraint: implement a Mix Mode option.

Allow selecting how the new location/rotation/scale is combined with
the existing transformation. This is most useful for rotation, which
has multiple options, and scale, which previously could only replace.

1 files changed, 44 insertions, 13 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 58011c8d753..9b32996aa96 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -3802,7 +3802,8 @@ static void transform_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
   /* only evaluate if there is a target */
   if (VALID_CONS_TARGET(ct)) {
     float *from_min, *from_max, *to_min, *to_max;
-    float loc[3], eul[3], size[3];
+    float loc[3], rot[3][3], oldeul[3], size[3];
+    float newloc[3], newrot[3][3], neweul[3], newsize[3];
     float dbuf[4], sval[3];
     float *const dvec = dbuf + 1;
     int i;
@@ -3844,9 +3845,7 @@ static void transform_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
     }
 
     /* extract components of owner's matrix */
-    copy_v3_v3(loc, cob->matrix[3]);
-    mat4_to_eulO(eul, rot_order, cob->matrix);
-    mat4_to_size(size, cob->matrix);
+    mat4_to_loc_rot_size(loc, rot, size, cob->matrix);
 
     /* determine where in range current transforms lie */
     if (data->expo) {
@@ -3878,18 +3877,42 @@ static void transform_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
         to_min = data->to_min_scale;
         to_max = data->to_max_scale;
         for (i = 0; i < 3; i++) {
-          /* multiply with original scale (so that it can still be scaled) */
-          /* size[i] *= to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i])); */
-          /* Stay absolute, else it breaks existing rigs... sigh. */
-          size[i] = to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i]));
+          newsize[i] = to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i]));
+        }
+        switch (data->mix_mode_scale) {
+          case TRANS_MIXSCALE_MULTIPLY:
+            mul_v3_v3(size, newsize);
+            break;
+          case TRANS_MIXSCALE_REPLACE:
+          default:
+            copy_v3_v3(size, newsize);
+            break;
         }
         break;
       case TRANS_ROTATION:
         to_min = data->to_min_rot;
         to_max = data->to_max_rot;
         for (i = 0; i < 3; i++) {
-          /* add to original rotation (so that it can still be rotated) */
-          eul[i] += to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i]));
+          neweul[i] = to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i]));
+        }
+        switch (data->mix_mode_rot) {
+          case TRANS_MIXROT_REPLACE:
+            eulO_to_mat3(rot, neweul, rot_order);
+            break;
+          case TRANS_MIXROT_BEFORE:
+            eulO_to_mat3(newrot, neweul, rot_order);
+            mul_m3_m3m3(rot, newrot, rot);
+            break;
+          case TRANS_MIXROT_AFTER:
+            eulO_to_mat3(newrot, neweul, rot_order);
+            mul_m3_m3m3(rot, rot, newrot);
+            break;
+          case TRANS_MIXROT_ADD:
+          default:
+            mat3_to_eulO(oldeul, rot_order, rot);
+            add_v3_v3(neweul, oldeul);
+            eulO_to_mat3(rot, neweul, rot_order);
+            break;
         }
         break;
       case TRANS_LOCATION:
@@ -3897,14 +3920,22 @@ static void transform_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
         to_min = data->to_min;
         to_max = data->to_max;
         for (i = 0; i < 3; i++) {
-          /* add to original location (so that it can still be moved) */
-          loc[i] += (to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i])));
+          newloc[i] = (to_min[i] + (sval[(int)data->map[i]] * (to_max[i] - to_min[i])));
+        }
+        switch (data->mix_mode_loc) {
+          case TRANS_MIXLOC_REPLACE:
+            copy_v3_v3(loc, newloc);
+            break;
+          case TRANS_MIXLOC_ADD:
+          default:
+            add_v3_v3(loc, newloc);
+            break;
         }
         break;
     }
 
     /* apply to matrix */
-    loc_eulO_size_to_mat4(cob->matrix, loc, eul, size, rot_order);
+    loc_rot_size_to_mat4(cob->matrix, loc, rot, size);
   }
 }