Animation: allow manually setting the intended playback range for actions.

Some operations, e.g. adding a new action strip to NLA, require
knowing the active frame range of an action. However, currently it
can only be deduced by scanning the keyframes of the curves within
it. This is not ideal if e.g. curves are staggered for overlap.

As suggested by Nathan Vegdahl in comments to T54724, this patch adds
Action properties that allow manually specifying its active frame range.
The settings are exposed via a panel in the Dopesheet and Action Editor.
When enabled, the range is highlighted in the background using a striped
fill to distinguish it from the solid filled regular playback range.

When set, the frame range is used when adding or updating NLA tracks,
and by add-ons using `Action.frame_range`, e.g. FBX exporter.

Differential Revision: https://developer.blender.org/D11803

1 files changed, 99 insertions, 5 deletions

diff --git a/source/blender/makesrna/intern/rna_action.c b/source/blender/makesrna/intern/rna_action.c
index 2aa09a30c75..db2c415c918 100644
--- a/source/blender/makesrna/intern/rna_action.c
+++ b/source/blender/makesrna/intern/rna_action.c
@@ -246,12 +246,60 @@ static void rna_Action_active_pose_marker_index_range(
   *max = max_ii(0, BLI_listbase_count(&act->markers) - 1);
 }
 
-static void rna_Action_frame_range_get(PointerRNA *ptr, float *values)
+static void rna_Action_frame_range_get(PointerRNA *ptr, float *r_values)
+{
+  BKE_action_get_frame_range((bAction *)ptr->owner_id, &r_values[0], &r_values[1]);
+}
+
+static void rna_Action_frame_range_set(PointerRNA *ptr, const float *values)
+{
+  bAction *data = (bAction *)ptr->owner_id;
+
+  data->flag |= ACT_FRAME_RANGE;
+  data->frame_start = values[0];
+  data->frame_end = values[1];
+  CLAMP_MIN(data->frame_end, data->frame_start);
+}
+
+static void rna_Action_curve_frame_range_get(PointerRNA *ptr, float *values)
 { /* don't include modifiers because they too easily can have very large
    * ranges: MINAFRAMEF to MAXFRAMEF. */
   calc_action_range((bAction *)ptr->owner_id, values, values + 1, false);
 }
 
+static void rna_Action_use_frame_range_set(PointerRNA *ptr, bool value)
+{
+  bAction *data = (bAction *)ptr->owner_id;
+
+  if (value) {
+    /* If the frame range is blank, initialize it by scanning F-Curves. */
+    if ((data->frame_start == data->frame_end) && (data->frame_start == 0)) {
+      calc_action_range(data, &data->frame_start, &data->frame_end, false);
+    }
+
+    data->flag |= ACT_FRAME_RANGE;
+  }
+  else {
+    data->flag &= ~ACT_FRAME_RANGE;
+  }
+}
+
+static void rna_Action_start_frame_set(PointerRNA *ptr, float value)
+{
+  bAction *data = (bAction *)ptr->owner_id;
+
+  data->frame_start = value;
+  CLAMP_MIN(data->frame_end, data->frame_start);
+}
+
+static void rna_Action_end_frame_set(PointerRNA *ptr, float value)
+{
+  bAction *data = (bAction *)ptr->owner_id;
+
+  data->frame_end = value;
+  CLAMP_MAX(data->frame_start, data->frame_end);
+}
+
 /* Used to check if an action (value pointer)
  * is suitable to be assigned to the ID-block that is ptr. */
 bool rna_Action_id_poll(PointerRNA *ptr, PointerRNA value)
@@ -834,17 +882,63 @@ static void rna_def_action(BlenderRNA *brna)
   rna_def_action_pose_markers(brna, prop);
 
   /* properties */
+  prop = RNA_def_property(srna, "use_frame_range", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", ACT_FRAME_RANGE);
+  RNA_def_property_boolean_funcs(prop, NULL, "rna_Action_use_frame_range_set");
+  RNA_def_property_ui_text(
+      prop,
+      "Manual Frame Range",
+      "Manually specify the intended playback frame range for the action "
+      "(this range is used by some tools, but does not affect animation evaluation)");
+  RNA_def_property_update(prop, NC_ANIMATION | ND_ANIMCHAN | NA_EDITED, NULL);
+
+  prop = RNA_def_property(srna, "frame_start", PROP_FLOAT, PROP_TIME);
+  RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+  RNA_def_property_float_sdna(prop, NULL, "frame_start");
+  RNA_def_property_float_funcs(prop, NULL, "rna_Action_start_frame_set", NULL);
+  RNA_def_property_ui_range(prop, MINFRAME, MAXFRAME, 100, 0);
+  RNA_def_property_ui_text(
+      prop, "Start Frame", "The start frame of the manually set intended playback range");
+  RNA_def_property_update(prop, NC_ANIMATION | ND_ANIMCHAN | NA_EDITED, NULL);
+
+  prop = RNA_def_property(srna, "frame_end", PROP_FLOAT, PROP_TIME);
+  RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+  RNA_def_property_float_sdna(prop, NULL, "frame_end");
+  RNA_def_property_float_funcs(prop, NULL, "rna_Action_end_frame_set", NULL);
+  RNA_def_property_ui_range(prop, MINFRAME, MAXFRAME, 100, 0);
+  RNA_def_property_ui_text(
+      prop, "End Frame", "The end frame of the manually set intended playback range");
+  RNA_def_property_update(prop, NC_ANIMATION | ND_ANIMCHAN | NA_EDITED, NULL);
+
+  prop = RNA_def_float_vector(
+      srna,
+      "frame_range",
+      2,
+      NULL,
+      0,
+      0,
+      "Frame Range",
+      "The intended playback frame range of this action, using the manually set range "
+      "if available, or the combined frame range of all F-Curves within this action "
+      "if not (assigning sets the manual frame range)",
+      0,
+      0);
+  RNA_def_property_float_funcs(
+      prop, "rna_Action_frame_range_get", "rna_Action_frame_range_set", NULL);
+  RNA_def_property_update(prop, NC_ANIMATION | ND_ANIMCHAN | NA_EDITED, NULL);
+
   prop = RNA_def_float_vector(srna,
-                              "frame_range",
+                              "curve_frame_range",
                               2,
                               NULL,
                               0,
                               0,
-                              "Frame Range",
-                              "The final frame range of all F-Curves within this action",
+                              "Curve Frame Range",
+                              "The combined frame range of all F-Curves within this action",
                               0,
                               0);
-  RNA_def_property_float_funcs(prop, "rna_Action_frame_range_get", NULL, NULL);
+  RNA_def_property_float_funcs(prop, "rna_Action_curve_frame_range_get", NULL, NULL);
   RNA_def_property_clear_flag(prop, PROP_EDITABLE);
 
   /* special "type" limiter - should not really be edited in general,