Breakdown Implementation

This patch adds the breakdown (or tween) functionality to the graph editor.

The factor defines the linear interpolation from left key to right key.

Reviewed by: Sybren A. Stüvel
Differential Revision: https://developer.blender.org/D9375
Ref: D9375

6 files changed, 142 insertions, 1 deletions

diff --git a/release/scripts/startup/bl_ui/space_graph.py b/release/scripts/startup/bl_ui/space_graph.py
index 497d68f88ca..3a668f61539 100644
--- a/release/scripts/startup/bl_ui/space_graph.py
+++ b/release/scripts/startup/bl_ui/space_graph.py
@@ -344,7 +344,8 @@ class GRAPH_MT_slider(Menu):
 
     def draw(self, _context):
         layout = self.layout
-
+        
+        layout.operator("graph.breakdown", text="Breakdown")
         layout.operator("graph.blend_to_neighbor", text="Blend To Neighbor")
 
 
diff --git a/source/blender/editors/animation/keyframes_general.c b/source/blender/editors/animation/keyframes_general.c
index 3c2e66d9367..8aac1e9b779 100644
--- a/source/blender/editors/animation/keyframes_general.c
+++ b/source/blender/editors/animation/keyframes_general.c
@@ -400,6 +400,18 @@ void blend_to_neighbor_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const
 
 /* ---------------- */
 
+void breakdown_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float factor)
+{
+  BezTriple left_bezt = fcurve_segment_start_get(fcu, segment->start_index);
+  BezTriple right_bezt = fcurve_segment_end_get(fcu, segment->start_index + segment->length);
+
+  for (int i = segment->start_index; i < segment->start_index + segment->length; i++) {
+    fcu->bezt[i].vec[1][1] = interpf(right_bezt.vec[1][1], left_bezt.vec[1][1], factor);
+  }
+}
+
+/* ---------------- */
+
 /* Check if the keyframe interpolation type is supported */
 static bool prepare_for_decimate(FCurve *fcu, int i)
 {
diff --git a/source/blender/editors/include/ED_keyframes_edit.h b/source/blender/editors/include/ED_keyframes_edit.h
index 084da038604..c54fb93e495 100644
--- a/source/blender/editors/include/ED_keyframes_edit.h
+++ b/source/blender/editors/include/ED_keyframes_edit.h
@@ -392,6 +392,9 @@ void clean_fcurve(struct bAnimContext *ac,
 void blend_to_neighbor_fcurve_segment(struct FCurve *fcu,
                                       struct FCurveSegment *segment,
                                       const float factor);
+void breakdown_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 ed52e684eb7..286580b5629 100644
--- a/source/blender/editors/space_graph/graph_intern.h
+++ b/source/blender/editors/space_graph/graph_intern.h
@@ -127,6 +127,7 @@ 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_breakdown(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 724d5351283..fe4cffcb3b8 100644
--- a/source/blender/editors/space_graph/graph_ops.c
+++ b/source/blender/editors/space_graph/graph_ops.c
@@ -471,6 +471,7 @@ void graphedit_operatortypes(void)
   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_breakdown);
   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 a78e65aa3d6..733313dd06b 100644
--- a/source/blender/editors/space_graph/graph_slider_ops.c
+++ b/source/blender/editors/space_graph/graph_slider_ops.c
@@ -681,3 +681,126 @@ void GRAPH_OT_blend_to_neighbor(wmOperatorType *ot)
 }
 
 /** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Breakdown Operator
+ * \{ */
+
+static void breakdown_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;
+
+  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) {
+      breakdown_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 breakdown_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_("Breakdown"));
+
+  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 breakdown_modal_update(bContext *C, wmOperator *op)
+{
+  tGraphSliderOp *gso = op->customdata;
+
+  breakdown_draw_status_header(C, gso);
+
+  /* Reset keyframe data to the state at invoke. */
+  reset_bezts(gso);
+  breakdown_graph_keys(&gso->ac, ED_slider_factor_get(gso->slider));
+  WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_EDITED, NULL);
+}
+
+static int breakdown_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 = breakdown_modal_update;
+  breakdown_draw_status_header(C, gso);
+
+  return invoke_result;
+}
+
+static int breakdown_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");
+
+  breakdown_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_breakdown(wmOperatorType *ot)
+{
+  /* Identifiers. */
+  ot->name = "Breakdown";
+  ot->idname = "GRAPH_OT_breakdown";
+  ot->description = "Move selected keyframes to an inbetween position relative to adjacent keys";
+
+  /* API callbacks. */
+  ot->invoke = breakdown_invoke;
+  ot->modal = graph_slider_modal;
+  ot->exec = breakdown_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,
+                       "Factor",
+                       "Favor either the left or the right key",
+                       0.0f,
+                       1.0f);
+}
+
+/** \} */