Remove Sticky option from the Floor constraint

This option from the very beginning of its existence needed more work
to make it work correct and this was never done.

This option was working fine during continuous playback, when there
are no skipped frames, but it was failing when AV-sync of framedrop
was enabled.
It was never working correct when jumping between frames, including
rendering on a farm which usually does frame-range based rendering.

With copy-on-write things became even more tricky, since the "stuck"
flag was never preserved between re-evaluations.

Fixes T65683: Sticky Option in Floor Constraint for Bones Not Working

release/scripts/startup/bl_ui/properties_constraint.py

@@ -548,10 +548,7 @@ class ConstraintButtonsPanel:
     def FLOOR(self, _context, layout, con):
         self.target_template(layout, con)
 
-        row = layout.row()
-        row.prop(con, "use_sticky")
-        row.prop(con, "use_rotation")
-
+        layout.prop(con, "use_rotation")
         layout.prop(con, "offset")
 
         row = layout.row()

source/blender/blenkernel/intern/constraint.c

@@ -3329,7 +3329,6 @@ static void minmax_new_data(void *cdata)
 
   data->minmaxflag = TRACK_Z;
   data->offset = 0.0f;
-  zero_v3(data->cache);
   data->flag = 0;
 }
 
@@ -3426,15 +3425,6 @@ static void minmax_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targ
 
     if (val1 > val2) {
       obmat[3][index] = tarmat[3][index] + data->offset;
-      if (data->flag & MINMAX_STICKY) {
-        if (data->flag & MINMAX_STUCK) {
-          copy_v3_v3(obmat[3], data->cache);
-        }
-        else {
-          copy_v3_v3(data->cache, obmat[3]);
-          data->flag |= MINMAX_STUCK;
-        }
-      }
       if (data->flag & MINMAX_USEROT) {
         /* get out of localspace */
         mul_m4_m4m4(tmat, ct->matrix, obmat);
@@ -3444,9 +3434,6 @@ static void minmax_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targ
         copy_v3_v3(cob->matrix[3], obmat[3]);
       }
     }
-    else {
-      data->flag &= ~MINMAX_STUCK;
-    }
   }
 }
 

source/blender/blenloader/intern/versioning_legacy.c

@@ -1738,17 +1738,6 @@ void blo_do_versions_pre250(FileData *fd, Library *lib, Main *bmain)
         bConstraint *curcon;
         for (curcon = list->first; curcon; curcon = curcon->next) {
           switch (curcon->type) {
-            case CONSTRAINT_TYPE_MINMAX: {
-              bMinMaxConstraint *data = curcon->data;
-              if (data->sticky == 1) {
-                data->flag |= MINMAX_STICKY;
-              }
-              else {
-                data->flag &= ~MINMAX_STICKY;
-              }
-
-              break;
-            }
             case CONSTRAINT_TYPE_ROTLIKE: {
               bRotateLikeConstraint *data = curcon->data;
 
@@ -1770,16 +1759,6 @@ void blo_do_versions_pre250(FileData *fd, Library *lib, Main *bmain)
           for (pchan = ob->pose->chanbase.first; pchan; pchan = pchan->next) {
             for (curcon = pchan->constraints.first; curcon; curcon = curcon->next) {
               switch (curcon->type) {
-                case CONSTRAINT_TYPE_MINMAX: {
-                  bMinMaxConstraint *data = curcon->data;
-                  if (data->sticky == 1) {
-                    data->flag |= MINMAX_STICKY;
-                  }
-                  else {
-                    data->flag &= ~MINMAX_STICKY;
-                  }
-                  break;
-                }
                 case CONSTRAINT_TYPE_KINEMATIC: {
                   bKinematicConstraint *data = curcon->data;
                   if (!(data->flag & CONSTRAINT_IK_POS)) {

source/blender/makesdna/DNA_constraint_types.h

@@ -315,12 +315,9 @@ typedef struct bMinMaxConstraint {
   int minmaxflag;
   float offset;
   int flag;
-  /** For backward compatibility. */
-  short sticky, stuck;
-  char _pad[4];
-  float cache[3];
   /** MAX_ID_NAME-2. */
   char subtarget[64];
+  int _pad;
 } bMinMaxConstraint;
 
 /* Action Constraint */
@@ -945,8 +942,8 @@ typedef enum eArmature_Flags {
 
 /* MinMax (floor) flags */
 typedef enum eFloor_Flags {
-  MINMAX_STICKY = (1 << 0),
-  MINMAX_STUCK = (1 << 1),
+  /* MINMAX_STICKY = (1 << 0), */ /* Deprecated. */
+  /* MINMAX_STUCK = (1 << 1), */  /* Deprecated. */
   MINMAX_USEROT = (1 << 2),
 } eFloor_Flags;
 

source/blender/makesrna/intern/rna_constraint.c

@@ -1483,11 +1483,6 @@ static void rna_def_constraint_minmax(BlenderRNA *brna)
       prop, "Floor Location", "Location of target that object will not pass through");
   RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_update");
 
-  prop = RNA_def_property(srna, "use_sticky", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, NULL, "flag", MINMAX_STICKY);
-  RNA_def_property_ui_text(prop, "Sticky", "Immobilize object while constrained");
-  RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_update");
-
   prop = RNA_def_property(srna, "use_rotation", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "flag", MINMAX_USEROT);
   RNA_def_property_ui_text(prop, "Use Rotation", "Use the target's rotation to determine floor");