Assets: Store Action sub-type in asset metadata

Blender 3.0 will only support single-frame Actions in the pose library.
The goal of this patch is to lay the groundwork for making it possible
for the Asset Browser to reject/hide "animation snippet" Action assets.

Determining whether an Action has one or more frames (i.e. whether it
has a single pose or animation) requires inspecting the Action itself,
and thus loading the data-block itself. This would make it impossible to
quickly determine from the asset browser.

To solve this, the Action is inspected before saving, and a
`"is_single_frame"` boolean (well, 0/1 integer) IDProperty is added.

Reviewed by: Severin

Differential Revision: https://developer.blender.org/D13202

1 files changed, 95 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/action_test.cc b/source/blender/blenkernel/intern/action_test.cc
index c02eca966ad..c0d9a4c6055 100644
--- a/source/blender/blenkernel/intern/action_test.cc
+++ b/source/blender/blenkernel/intern/action_test.cc
@@ -24,6 +24,8 @@
 
 #include "BLI_listbase.h"
 
+#include "MEM_guardedalloc.h"
+
 #include "testing/testing.h"
 
 namespace blender::bke::tests {
@@ -141,4 +143,97 @@ TEST(action_groups, ReconstructGroupsWithReordering)
   EXPECT_EQ(groupDcurve2.next, nullptr);
 }
 
+namespace {
+
+/* Allocate fcu->bezt, and also return a unique_ptr to it for easily freeing the memory. */
+std::unique_ptr<BezTriple[]> allocate_keyframes(FCurve *fcu, const size_t num_keyframes)
+{
+  auto bezt_uptr = std::make_unique<BezTriple[]>(num_keyframes);
+  fcu->bezt = bezt_uptr.get();
+  return bezt_uptr;
+}
+
+/* Append keyframe, assumes that fcu->bezt is allocated and has enough space. */
+void add_keyframe(FCurve *fcu, float x, float y)
+{
+  /* The insert_keyframe functions are in the editors, so we cannot link to those here. */
+  BezTriple the_keyframe;
+  memset(&the_keyframe, 0, sizeof(the_keyframe));
+
+  /* Copied from insert_vert_fcurve() in keyframing.c. */
+  the_keyframe.vec[0][0] = x - 1.0f;
+  the_keyframe.vec[0][1] = y;
+  the_keyframe.vec[1][0] = x;
+  the_keyframe.vec[1][1] = y;
+  the_keyframe.vec[2][0] = x + 1.0f;
+  the_keyframe.vec[2][1] = y;
+
+  memcpy(&fcu->bezt[fcu->totvert], &the_keyframe, sizeof(the_keyframe));
+  fcu->totvert++;
+}
+
+}  // namespace
+
+TEST(action_assets, BKE_action_has_single_frame)
+{
+  /* NULL action. */
+  EXPECT_FALSE(BKE_action_has_single_frame(nullptr)) << "NULL Action cannot have a single frame.";
+
+  /* No FCurves. */
+  {
+    const bAction empty = {nullptr};
+    EXPECT_FALSE(BKE_action_has_single_frame(&empty))
+        << "Action without FCurves cannot have a single frame.";
+  }
+
+  /* One curve with one key. */
+  {
+    FCurve fcu = {nullptr};
+    std::unique_ptr<BezTriple[]> bezt = allocate_keyframes(&fcu, 1);
+    add_keyframe(&fcu, 1.0f, 2.0f);
+
+    bAction action = {nullptr};
+    BLI_addtail(&action.curves, &fcu);
+
+    EXPECT_TRUE(BKE_action_has_single_frame(&action))
+        << "Action with one FCurve and one key should have single frame.";
+  }
+
+  /* Two curves with one key each. */
+  {
+    FCurve fcu1 = {nullptr};
+    FCurve fcu2 = {nullptr};
+    std::unique_ptr<BezTriple[]> bezt1 = allocate_keyframes(&fcu1, 1);
+    std::unique_ptr<BezTriple[]> bezt2 = allocate_keyframes(&fcu2, 1);
+    add_keyframe(&fcu1, 1.0f, 327.0f);
+    add_keyframe(&fcu2, 1.0f, 47.0f); /* Same X-coordinate as the other one. */
+
+    bAction action = {nullptr};
+    BLI_addtail(&action.curves, &fcu1);
+    BLI_addtail(&action.curves, &fcu2);
+
+    EXPECT_TRUE(BKE_action_has_single_frame(&action))
+        << "Two FCurves with keys on the same frame should have single frame.";
+
+    /* Modify the 2nd curve so it's keyed on a different frame. */
+    fcu2.bezt[0].vec[1][0] = 2.0f;
+    EXPECT_FALSE(BKE_action_has_single_frame(&action))
+        << "Two FCurves with keys on different frames should have animation.";
+  }
+
+  /* One curve with two keys. */
+  {
+    FCurve fcu = {nullptr};
+    std::unique_ptr<BezTriple[]> bezt = allocate_keyframes(&fcu, 2);
+    add_keyframe(&fcu, 1.0f, 2.0f);
+    add_keyframe(&fcu, 2.0f, 2.5f);
+
+    bAction action = {nullptr};
+    BLI_addtail(&action.curves, &fcu);
+
+    EXPECT_FALSE(BKE_action_has_single_frame(&action))
+        << "Action with one FCurve and two keys must have animation.";
+  }
+}
+
 }  // namespace blender::bke::tests