scripts/startup/bl_ui/space_graph.py

@@ -327,6 +327,7 @@ class GRAPH_MT_key_blending(Menu):
         layout.operator("graph.push_pull", text="Push Pull")
         layout.operator("graph.shear", text="Shear Keys")
         layout.operator("graph.scale_average", text="Scale Average")
+        layout.operator("graph.time_offset", text="Time Offset")
 
 
 class GRAPH_MT_key_smoothing(Menu):

source/blender/editors/animation/keyframes_general.cc

@@ -910,6 +910,41 @@ void push_pull_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float f
 
 /* ---------------- */
 
+void time_offset_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float frame_offset)
+{
+  /* Two bookend keys of the fcurve are needed to be able to cycle the values. */
+  const BezTriple *last_key = &fcu->bezt[fcu->totvert - 1];
+  const BezTriple *first_key = &fcu->bezt[0];
+
+  const float fcu_x_range = last_key->vec[1][0] - first_key->vec[1][0];
+  const float fcu_y_range = last_key->vec[1][1] - first_key->vec[1][1];
+
+  const float first_key_x = first_key->vec[1][0];
+
+  /* If we operate directly on the fcurve there will be a feedback loop
+   * so we need to capture the "y" values on an array to then apply them on a second loop. */
+  float *y_values = static_cast<float *>(
+      MEM_callocN(sizeof(float) * segment->length, "Time Offset Samples"));
+
+  for (int i = 0; i < segment->length; i++) {
+    /* This simulates the fcu curve moving in time. */
+    const float time = fcu->bezt[segment->start_index + i].vec[1][0] + frame_offset;
+    /* Need to normalize time to first_key to specify that as the wrapping point. */
+    const float wrapped_time = mod_f_positive(time - first_key_x, fcu_x_range) + first_key_x;
+    const float delta_y = fcu_y_range * floorf((time - first_key_x) / fcu_x_range);
+
+    const float key_y_value = evaluate_fcurve(fcu, wrapped_time) + delta_y;
+    y_values[i] = key_y_value;
+  }
+
+  for (int i = 0; i < segment->length; i++) {
+    BKE_fcurve_keyframe_move_value_with_handles(&fcu->bezt[segment->start_index + i], y_values[i]);
+  }
+  MEM_freeN(y_values);
+}
+
+/* ---------------- */
+
 void breakdown_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float factor)
 {
   const BezTriple *left_bezt = fcurve_segment_start_get(fcu, segment->start_index);

source/blender/editors/include/ED_keyframes_edit.hh

@@ -476,6 +476,7 @@ void shear_fcurve_segment(struct FCurve *fcu,
  */
 void blend_offset_fcurve_segment(FCurve *fcu, FCurveSegment *segment, float factor);
 void blend_to_ease_fcurve_segment(FCurve *fcu, FCurveSegment *segment, float factor);
+void time_offset_fcurve_segment(FCurve *fcu, FCurveSegment *segment, float frame_offset);
 bool decimate_fcurve(bAnimListElem *ale, float remove_ratio, float error_sq_max);
 bool match_slope_fcurve_segment(FCurve *fcu, FCurveSegment *segment, float factor);
 

source/blender/editors/space_graph/graph_intern.h

@@ -125,6 +125,7 @@ void GRAPH_OT_match_slope(struct wmOperatorType *ot);
 void GRAPH_OT_shear(struct wmOperatorType *ot);
 void GRAPH_OT_scale_average(struct wmOperatorType *ot);
 void GRAPH_OT_push_pull(struct wmOperatorType *ot);
+void GRAPH_OT_time_offset(struct wmOperatorType *ot);
 void GRAPH_OT_decimate(struct wmOperatorType *ot);
 void GRAPH_OT_blend_to_default(struct wmOperatorType *ot);
 void GRAPH_OT_butterworth_smooth(struct wmOperatorType *ot);

source/blender/editors/space_graph/graph_ops.cc

@@ -474,6 +474,7 @@ void graphedit_operatortypes()
   WM_operatortype_append(GRAPH_OT_blend_offset);
   WM_operatortype_append(GRAPH_OT_blend_to_ease);
   WM_operatortype_append(GRAPH_OT_match_slope);
+  WM_operatortype_append(GRAPH_OT_time_offset);
   WM_operatortype_append(GRAPH_OT_blend_to_default);
   WM_operatortype_append(GRAPH_OT_push_pull);
   WM_operatortype_append(GRAPH_OT_gaussian_smooth);

source/blender/editors/space_graph/graph_slider_ops.cc

@@ -1289,6 +1289,99 @@ void GRAPH_OT_match_slope(wmOperatorType *ot)
                        1.0f);
 }
 
+/* -------------------------------------------------------------------- */
+/** \name Time Offset
+ * \{ */
+
+static void time_offset_graph_keys(bAnimContext *ac, const float factor)
+{
+  apply_fcu_segment_function(ac, factor, time_offset_fcurve_segment);
+}
+
+static void time_offset_draw_status_header(bContext *C, tGraphSliderOp *gso)
+{
+  common_draw_status_header(C, gso, "Time Offset Keys");
+}
+
+static void time_offset_modal_update(bContext *C, wmOperator *op)
+{
+  tGraphSliderOp *gso = static_cast<tGraphSliderOp *>(op->customdata);
+
+  time_offset_draw_status_header(C, gso);
+
+  /* Reset keyframes to the state at invoke. */
+  reset_bezts(gso);
+  const float factor = slider_factor_get_and_remember(op);
+  time_offset_graph_keys(&gso->ac, factor);
+  WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_EDITED, NULL);
+}
+
+static int time_offset_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 = static_cast<tGraphSliderOp *>(op->customdata);
+  gso->modal_update = time_offset_modal_update;
+  gso->factor_prop = RNA_struct_find_property(op->ptr, "frame_offset");
+  time_offset_draw_status_header(C, gso);
+  ED_slider_factor_bounds_set(gso->slider, -10, 10);
+  ED_slider_factor_set(gso->slider, 0.0f);
+  ED_slider_mode_set(gso->slider, SLIDER_MODE_FLOAT);
+  ED_slider_unit_set(gso->slider, "Frames");
+
+  return invoke_result;
+}
+
+static int time_offset_exec(bContext *C, wmOperator *op)
+{
+  bAnimContext ac;
+
+  /* Get editor data. */
+  if (ANIM_animdata_get_context(C, &ac) == 0) {
+    return OPERATOR_CANCELLED;
+  }
+
+  const float factor = RNA_float_get(op->ptr, "frame_offset");
+
+  time_offset_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_time_offset(wmOperatorType *ot)
+{
+  /* Identifiers. */
+  ot->name = "Time Offset Keyframes";
+  ot->idname = "GRAPH_OT_time_offset";
+  ot->description = "Shifts the value of selected keys in time";
+
+  /* API callbacks. */
+  ot->invoke = time_offset_invoke;
+  ot->modal = graph_slider_modal;
+  ot->exec = time_offset_exec;
+  ot->poll = graphop_editable_keyframes_poll;
+
+  /* Flags. */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO | OPTYPE_BLOCKING | OPTYPE_GRAB_CURSOR_X;
+
+  RNA_def_float_factor(ot->srna,
+                       "frame_offset",
+                       0.0f,
+                       -FLT_MAX,
+                       FLT_MAX,
+                       "Frame Offset",
+                       "How far in frames to offset the animation",
+                       -10.0f,
+                       10.0f);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */