Blend To Neighbor Implementation

This patch adds the blend to neighbor operator to the Graph editor.

The operator acts like the blend to neighbor operator for a pose context, just working on keyframes.

Reviewed by: Sybren A. Stüvel
Differential Revision: https://developer.blender.org/D9374
Ref: D9374

7 files changed, 177 insertions, 0 deletions

diff --git a/release/scripts/addons b/release/scripts/addons
-Subproject c60fef38175ad989ee0c45e924cb27e1417c866
+Subproject c08568cc376d2e4298710c4172fb0c74f0611de
diff --git a/release/scripts/startup/bl_ui/space_graph.py b/release/scripts/startup/bl_ui/space_graph.py
index 1562870d64f..497d68f88ca 100644
--- a/release/scripts/startup/bl_ui/space_graph.py
+++ b/release/scripts/startup/bl_ui/space_graph.py
@@ -298,6 +298,8 @@ class GRAPH_MT_key(Menu):
         layout.operator("graph.decimate", text="Decimate (Allowed Change)").mode = 'ERROR'
         layout.operator_context = operator_context
 
+        layout.menu("GRAPH_MT_slider", text="Slider Operators")
+
         layout.operator("graph.clean").channels = False
         layout.operator("graph.clean", text="Clean Channels").channels = True
         layout.operator("graph.smooth")
@@ -337,6 +339,14 @@ class GRAPH_MT_key_snap(Menu):
         layout.operator("graph.frame_jump", text="Cursor to Selection")
         layout.operator("graph.snap_cursor_value", text="Cursor Value to Selection")
 
+class GRAPH_MT_slider(Menu):
+    bl_label = "Slider Operators"
+
+    def draw(self, _context):
+        layout = self.layout
+
+        layout.operator("graph.blend_to_neighbor", text="Blend To Neighbor")
+
 
 class GRAPH_MT_view_pie(Menu):
     bl_label = "View"
@@ -475,6 +485,7 @@ classes = (
     GRAPH_MT_key,
     GRAPH_MT_key_transform,
     GRAPH_MT_key_snap,
+    GRAPH_MT_slider,
     GRAPH_MT_delete,
     GRAPH_MT_context_menu,
     GRAPH_MT_channel_context_menu,
diff --git a/source/blender/editors/animation/keyframes_general.c b/source/blender/editors/animation/keyframes_general.c
index 4fa5dee99a6..3c2e66d9367 100644
--- a/source/blender/editors/animation/keyframes_general.c
+++ b/source/blender/editors/animation/keyframes_general.c
@@ -367,6 +367,37 @@ ListBase find_fcurve_segments(FCurve *fcu)
   return segments;
 }
 
+static BezTriple fcurve_segment_start_get(FCurve *fcu, int index)
+{
+  BezTriple start_bezt = index - 1 >= 0 ? fcu->bezt[index - 1] : fcu->bezt[index];
+  return start_bezt;
+}
+
+static BezTriple fcurve_segment_end_get(FCurve *fcu, int index)
+{
+  BezTriple end_bezt = index < fcu->totvert ? fcu->bezt[index] : fcu->bezt[index - 1];
+  return end_bezt;
+}
+
+/* ---------------- */
+
+void blend_to_neighbor_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float factor)
+{
+  const float blend_factor = fabs(factor * 2 - 1);
+  BezTriple target_bezt;
+  /* Find which key to blend towards. */
+  if (factor < 0.5f) {
+    target_bezt = fcurve_segment_start_get(fcu, segment->start_index);
+  }
+  else {
+    target_bezt = fcurve_segment_end_get(fcu, segment->start_index + segment->length);
+  }
+  /* Blend each key individually. */
+  for (int i = segment->start_index; i < segment->start_index + segment->length; i++) {
+    fcu->bezt[i].vec[1][1] = interpf(target_bezt.vec[1][1], fcu->bezt[i].vec[1][1], blend_factor);
+  }
+}
+
 /* ---------------- */
 
 /* Check if the keyframe interpolation type is supported */
diff --git a/source/blender/editors/include/ED_keyframes_edit.h b/source/blender/editors/include/ED_keyframes_edit.h
index 8a7831db0ea..084da038604 100644
--- a/source/blender/editors/include/ED_keyframes_edit.h
+++ b/source/blender/editors/include/ED_keyframes_edit.h
@@ -389,6 +389,9 @@ void clean_fcurve(struct bAnimContext *ac,
                   struct bAnimListElem *ale,
                   float thresh,
                   bool cleardefault);
+void blend_to_neighbor_fcurve_segment(struct FCurve *fcu,
+                                      struct FCurveSegment *segment,
+                                      const float factor);
 bool decimate_fcurve(struct bAnimListElem *ale, float remove_ratio, float error_sq_max);
 /**
  * Use a weighted moving-means method to reduce intensity of fluctuations.
diff --git a/source/blender/editors/space_graph/graph_intern.h b/source/blender/editors/space_graph/graph_intern.h
index 4db1eb5214e..ed52e684eb7 100644
--- a/source/blender/editors/space_graph/graph_intern.h
+++ b/source/blender/editors/space_graph/graph_intern.h
@@ -126,6 +126,7 @@ void GRAPH_OT_paste(struct wmOperatorType *ot);
 void GRAPH_OT_duplicate(struct wmOperatorType *ot);
 void GRAPH_OT_delete(struct wmOperatorType *ot);
 void GRAPH_OT_clean(struct wmOperatorType *ot);
+void GRAPH_OT_blend_to_neighbor(struct wmOperatorType *ot);
 void GRAPH_OT_decimate(struct wmOperatorType *ot);
 void GRAPH_OT_sample(struct wmOperatorType *ot);
 void GRAPH_OT_bake(struct wmOperatorType *ot);
diff --git a/source/blender/editors/space_graph/graph_ops.c b/source/blender/editors/space_graph/graph_ops.c
index ecafc75fc06..724d5351283 100644
--- a/source/blender/editors/space_graph/graph_ops.c
+++ b/source/blender/editors/space_graph/graph_ops.c
@@ -470,6 +470,7 @@ void graphedit_operatortypes(void)
   WM_operatortype_append(GRAPH_OT_smooth);
   WM_operatortype_append(GRAPH_OT_clean);
   WM_operatortype_append(GRAPH_OT_decimate);
+  WM_operatortype_append(GRAPH_OT_blend_to_neighbor);
   WM_operatortype_append(GRAPH_OT_euler_filter);
   WM_operatortype_append(GRAPH_OT_delete);
   WM_operatortype_append(GRAPH_OT_duplicate);
diff --git a/source/blender/editors/space_graph/graph_slider_ops.c b/source/blender/editors/space_graph/graph_slider_ops.c
index 30293f25332..a78e65aa3d6 100644
--- a/source/blender/editors/space_graph/graph_slider_ops.c
+++ b/source/blender/editors/space_graph/graph_slider_ops.c
@@ -551,3 +551,133 @@ void GRAPH_OT_decimate(wmOperatorType *ot)
 }
 
 /** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Blend To Neighbor Operator
+ * \{ */
+
+static void blend_to_neighbor_graph_keys(bAnimContext *ac, float factor)
+{
+  ListBase anim_data = {NULL, NULL};
+  ANIM_animdata_filter(ac, &anim_data, OPERATOR_DATA_FILTER, ac->data, ac->datatype);
+
+  bAnimListElem *ale;
+
+  /* Loop through filtered data and blend keys. */
+
+  for (ale = anim_data.first; ale; ale = ale->next) {
+    FCurve *fcu = (FCurve *)ale->key_data;
+    ListBase segments = find_fcurve_segments(fcu);
+    LISTBASE_FOREACH (FCurveSegment *, segment, &segments) {
+      blend_to_neighbor_fcurve_segment(fcu, segment, factor);
+    }
+    BLI_freelistN(&segments);
+    ale->update |= ANIM_UPDATE_DEFAULT;
+  }
+
+  ANIM_animdata_update(ac, &anim_data);
+  ANIM_animdata_freelist(&anim_data);
+}
+
+static void blend_to_neighbor_draw_status_header(bContext *C, tGraphSliderOp *gso)
+{
+  char status_str[UI_MAX_DRAW_STR];
+  char mode_str[32];
+  char slider_string[UI_MAX_DRAW_STR];
+
+  ED_slider_status_string_get(gso->slider, slider_string, UI_MAX_DRAW_STR);
+
+  strcpy(mode_str, TIP_("Blend To Neighbor"));
+
+  if (hasNumInput(&gso->num)) {
+    char str_ofs[NUM_STR_REP_LEN];
+
+    outputNumInput(&gso->num, str_ofs, &gso->scene->unit);
+
+    BLI_snprintf(status_str, sizeof(status_str), "%s: %s", mode_str, str_ofs);
+  }
+  else {
+    BLI_snprintf(status_str, sizeof(status_str), "%s: %s", mode_str, slider_string);
+  }
+
+  ED_workspace_status_text(C, status_str);
+}
+
+static void blend_to_neighbor_modal_update(bContext *C, wmOperator *op)
+{
+  tGraphSliderOp *gso = op->customdata;
+
+  blend_to_neighbor_draw_status_header(C, gso);
+
+  /* Reset keyframe data to the state at invoke. */
+  reset_bezts(gso);
+
+  const float factor = ED_slider_factor_get(gso->slider);
+  RNA_property_float_set(op->ptr, gso->factor_prop, factor);
+  blend_to_neighbor_graph_keys(&gso->ac, factor);
+
+  WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_EDITED, NULL);
+}
+
+static int blend_to_neighbor_invoke(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  const int invoke_result = graph_slider_invoke(C, op, event);
+
+  if (invoke_result == OPERATOR_CANCELLED) {
+    return invoke_result;
+  }
+
+  tGraphSliderOp *gso = op->customdata;
+  gso->modal_update = blend_to_neighbor_modal_update;
+  gso->factor_prop = RNA_struct_find_property(op->ptr, "factor");
+  blend_to_neighbor_draw_status_header(C, gso);
+
+  return invoke_result;
+}
+
+static int blend_to_neighbor_exec(bContext *C, wmOperator *op)
+{
+  bAnimContext ac;
+
+  if (ANIM_animdata_get_context(C, &ac) == 0) {
+    return OPERATOR_CANCELLED;
+  }
+
+  const float factor = RNA_float_get(op->ptr, "factor");
+
+  blend_to_neighbor_graph_keys(&ac, factor);
+
+  /* Set notifier that keyframes have changed. */
+  WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_EDITED, NULL);
+
+  return OPERATOR_FINISHED;
+}
+
+void GRAPH_OT_blend_to_neighbor(wmOperatorType *ot)
+{
+  /* Identifiers. */
+  ot->name = "Blend To Neighbor";
+  ot->idname = "GRAPH_OT_blend_to_neighbor";
+  ot->description = "Blend selected keyframes to their left or right neighbor";
+
+  /* API callbacks. */
+  ot->invoke = blend_to_neighbor_invoke;
+  ot->modal = graph_slider_modal;
+  ot->exec = blend_to_neighbor_exec;
+  ot->poll = graphop_editable_keyframes_poll;
+
+  /* Flags. */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  RNA_def_float_factor(ot->srna,
+                       "factor",
+                       1.0f / 3.0f,
+                       -FLT_MAX,
+                       FLT_MAX,
+                       "Blend",
+                       "The blend factor with 0.5 being the current frame",
+                       0.0f,
+                       1.0f);
+}
+
+/** \} */