14 files changed, 190 insertions, 19 deletions

diff --git a/intern/cycles/test/CMakeLists.txt b/intern/cycles/test/CMakeLists.txt
index 6dcc7f7b3dd..07b345baff8 100644
--- a/intern/cycles/test/CMakeLists.txt
+++ b/intern/cycles/test/CMakeLists.txt
@@ -112,3 +112,4 @@ set_source_files_properties(util_avxf_avx_test.cpp PROPERTIES COMPILE_FLAGS "${C
 CYCLES_TEST(util_avxf_avx "cycles_util;bf_intern_numaapi;${OPENIMAGEIO_LIBRARIES};${BOOST_LIBRARIES}")
 set_source_files_properties(util_avxf_avx2_test.cpp PROPERTIES COMPILE_FLAGS "${CYCLES_AVX2_KERNEL_FLAGS}")
 CYCLES_TEST(util_avxf_avx2 "cycles_util;bf_intern_numaapi;${OPENIMAGEIO_LIBRARIES};${BOOST_LIBRARIES}")
+CYCLES_TEST(util_transform "cycles_util;${OPENIMAGEIO_LIBRARIES};${BOOST_LIBRARIES}")
diff --git a/intern/cycles/test/util_transform_test.cpp b/intern/cycles/test/util_transform_test.cpp
new file mode 100644
index 00000000000..58ce0fdfee4
--- /dev/null
+++ b/intern/cycles/test/util_transform_test.cpp
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2011-2020 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "testing/testing.h"
+
+#include "util/util_transform.h"
+#include "util/util_vector.h"
+
+CCL_NAMESPACE_BEGIN
+
+TEST(transform_motion_decompose, Degenerated)
+{
+  // Simple case: single degenerated matrix.
+  {
+    vector<Transform> motion = {transform_scale(0.0f, 0.0f, 0.0f)};
+    vector<DecomposedTransform> decomp(motion.size());
+    transform_motion_decompose(decomp.data(), motion.data(), motion.size());
+    EXPECT_TRUE(transform_decomposed_isfinite_safe(&decomp[0]));
+  }
+
+  // Copy from previous to current.
+  {
+    vector<Transform> motion = {transform_rotate(M_PI_4_F, make_float3(1.0f, 1.0f, 1.0f)),
+                                transform_scale(0.0f, 0.0f, 0.0f)};
+    vector<DecomposedTransform> decomp(motion.size());
+    transform_motion_decompose(decomp.data(), motion.data(), motion.size());
+    EXPECT_NEAR(len(decomp[1].x - decomp[0].x), 0.0f, 1e-6f);
+  }
+
+  // Copy from next to current.
+  {
+    vector<Transform> motion = {transform_scale(0.0f, 0.0f, 0.0f),
+                                transform_rotate(M_PI_4_F, make_float3(1.0f, 1.0f, 1.0f))};
+    vector<DecomposedTransform> decomp(motion.size());
+    transform_motion_decompose(decomp.data(), motion.data(), motion.size());
+    EXPECT_NEAR(len(decomp[0].x - decomp[1].x), 0.0f, 1e-6f);
+  }
+}
+
+CCL_NAMESPACE_END
diff --git a/intern/cycles/util/util_math_float4.h b/intern/cycles/util/util_math_float4.h
index cd4b3e3b74c..ec5328adb31 100644
--- a/intern/cycles/util/util_math_float4.h
+++ b/intern/cycles/util/util_math_float4.h
@@ -477,6 +477,24 @@ ccl_device_inline float4 safe_divide_float4_float(const float4 a, const float b)
   return (b != 0.0f) ? a / b : make_float4(0.0f, 0.0f, 0.0f, 0.0f);
 }
 
+ccl_device_inline bool isfinite4_safe(float4 v)
+{
+  return isfinite_safe(v.x) && isfinite_safe(v.y) && isfinite_safe(v.z) && isfinite_safe(v.w);
+}
+
+ccl_device_inline float4 ensure_finite4(float4 v)
+{
+  if (!isfinite_safe(v.x))
+    v.x = 0.0f;
+  if (!isfinite_safe(v.y))
+    v.y = 0.0f;
+  if (!isfinite_safe(v.z))
+    v.z = 0.0f;
+  if (!isfinite_safe(v.w))
+    v.w = 0.0f;
+  return v;
+}
+
 CCL_NAMESPACE_END
 
 #endif /* __UTIL_MATH_FLOAT4_H__ */
diff --git a/intern/cycles/util/util_transform.cpp b/intern/cycles/util/util_transform.cpp
index 101122740d7..6417752f704 100644
--- a/intern/cycles/util/util_transform.cpp
+++ b/intern/cycles/util/util_transform.cpp
@@ -269,17 +269,17 @@ static void transform_decompose(DecomposedTransform *decomp, const Transform *tf
   /* extract scale and shear first */
   float3 scale, shear;
   scale.x = len(colx);
-  colx /= scale.x;
+  colx = safe_divide_float3_float(colx, scale.x);
   shear.z = dot(colx, coly);
   coly -= shear.z * colx;
   scale.y = len(coly);
-  coly /= scale.y;
+  coly = safe_divide_float3_float(coly, scale.y);
   shear.y = dot(colx, colz);
   colz -= shear.y * colx;
   shear.x = dot(coly, colz);
   colz -= shear.x * coly;
   scale.z = len(colz);
-  colz /= scale.z;
+  colz = safe_divide_float3_float(colz, scale.z);
 
   transform_set_column(&M, 0, colx);
   transform_set_column(&M, 1, coly);
@@ -300,6 +300,7 @@ static void transform_decompose(DecomposedTransform *decomp, const Transform *tf
 
 void transform_motion_decompose(DecomposedTransform *decomp, const Transform *motion, size_t size)
 {
+  /* Decompose and correct rotation. */
   for (size_t i = 0; i < size; i++) {
     transform_decompose(decomp + i, motion + i);
 
@@ -310,6 +311,27 @@ void transform_motion_decompose(DecomposedTransform *decomp, const Transform *mo
         decomp[i].x = -decomp[i].x;
     }
   }
+
+  /* Copy rotation to decomposed transform where scale is degenerate. This avoids weird object
+   * rotation interpolation when the scale goes to 0 for a time step.
+   *
+   * Note that this is very simple and naive implementation, which only deals with degenerated
+   * scale happening only on one frame. It is possible to improve it further by interpolating
+   * rotation into s degenerated range using rotation from timesteps from adjacent non-degenerated
+   * time steps. */
+  for (size_t i = 0; i < size; i++) {
+    const float3 scale = make_float3(decomp[i].y.w, decomp[i].z.w, decomp[i].w.w);
+    if (!is_zero(scale)) {
+      continue;
+    }
+
+    if (i > 0) {
+      decomp[i].x = decomp[i - 1].x;
+    }
+    else if (i < size - 1) {
+      decomp[i].x = decomp[i + 1].x;
+    }
+  }
 }
 
 Transform transform_from_viewplane(BoundBox2D &viewplane)
diff --git a/intern/cycles/util/util_transform.h b/intern/cycles/util/util_transform.h
index d0a6264d5cf..d8bbd389aa6 100644
--- a/intern/cycles/util/util_transform.h
+++ b/intern/cycles/util/util_transform.h
@@ -466,6 +466,17 @@ ccl_device void transform_motion_array_interpolate(Transform *tfm,
   transform_compose(tfm, &decomp);
 }
 
+ccl_device_inline bool transform_isfinite_safe(Transform *tfm)
+{
+  return isfinite4_safe(tfm->x) && isfinite4_safe(tfm->y) && isfinite4_safe(tfm->z);
+}
+
+ccl_device_inline bool transform_decomposed_isfinite_safe(DecomposedTransform *decomp)
+{
+  return isfinite4_safe(decomp->x) && isfinite4_safe(decomp->y) && isfinite4_safe(decomp->z) &&
+         isfinite4_safe(decomp->w);
+}
+
 #ifndef __KERNEL_GPU__
 
 class BoundBox2D;
diff --git a/source/blender/blenkernel/BKE_action.h b/source/blender/blenkernel/BKE_action.h
index b7904ce1879..c3cfd4b33ea 100644
--- a/source/blender/blenkernel/BKE_action.h
+++ b/source/blender/blenkernel/BKE_action.h
@@ -129,6 +129,8 @@ void BKE_pose_channel_free(struct bPoseChannel *pchan);
 void BKE_pose_channel_free_ex(struct bPoseChannel *pchan, bool do_id_user);
 
 void BKE_pose_channel_runtime_reset(struct bPoseChannel_Runtime *runtime);
+void BKE_pose_channel_runtime_reset_on_copy(struct bPoseChannel_Runtime *runtime);
+
 void BKE_pose_channel_runtime_free(struct bPoseChannel_Runtime *runtime);
 
 void BKE_pose_channel_free_bbone_cache(struct bPoseChannel_Runtime *runtime);
@@ -153,12 +155,15 @@ void BKE_pose_copy_data_ex(struct bPose **dst,
                            const bool copy_constraints);
 void BKE_pose_copy_data(struct bPose **dst, const struct bPose *src, const bool copy_constraints);
 void BKE_pose_channel_copy_data(struct bPoseChannel *pchan, const struct bPoseChannel *pchan_from);
+void BKE_pose_channel_session_uuid_generate(struct bPoseChannel *pchan);
 struct bPoseChannel *BKE_pose_channel_find_name(const struct bPose *pose, const char *name);
 struct bPoseChannel *BKE_pose_channel_active(struct Object *ob);
 struct bPoseChannel *BKE_pose_channel_active_or_first_selected(struct Object *ob);
 struct bPoseChannel *BKE_pose_channel_verify(struct bPose *pose, const char *name);
 struct bPoseChannel *BKE_pose_channel_get_mirrored(const struct bPose *pose, const char *name);
 
+void BKE_pose_check_uuids_unique_and_report(const struct bPose *pose);
+
 #ifndef NDEBUG
 bool BKE_pose_channels_is_valid(const struct bPose *pose);
 #endif
diff --git a/source/blender/blenkernel/intern/action.c b/source/blender/blenkernel/intern/action.c
index fa7eee83a68..85ac2c693cb 100644
--- a/source/blender/blenkernel/intern/action.c
+++ b/source/blender/blenkernel/intern/action.c
@@ -37,6 +37,7 @@
 #include "BLI_blenlib.h"
 #include "BLI_ghash.h"
 #include "BLI_math.h"
+#include "BLI_session_uuid.h"
 #include "BLI_string_utils.h"
 #include "BLI_utildefines.h"
 
@@ -482,6 +483,11 @@ void action_groups_clear_tempflags(bAction *act)
 
 /* *************** Pose channels *************** */
 
+void BKE_pose_channel_session_uuid_generate(bPoseChannel *pchan)
+{
+  pchan->runtime.session_uuid = BLI_session_uuid_generate();
+}
+
 /**
  * Return a pointer to the pose channel of the given name
  * from this pose.
@@ -524,6 +530,8 @@ bPoseChannel *BKE_pose_channel_verify(bPose *pose, const char *name)
   /* If not, create it and add it */
   chan = MEM_callocN(sizeof(bPoseChannel), "verifyPoseChannel");
 
+  BKE_pose_channel_session_uuid_generate(chan);
+
   BLI_strncpy(chan->name, name, sizeof(chan->name));
 
   chan->custom_scale = 1.0f;
@@ -698,6 +706,10 @@ void BKE_pose_copy_data_ex(bPose **dst,
       id_us_plus((ID *)pchan->custom);
     }
 
+    if ((flag & LIB_ID_CREATE_NO_MAIN) == 0) {
+      BKE_pose_channel_session_uuid_generate(pchan);
+    }
+
     /* warning, O(n2) here, if done without the hash, but these are rarely used features. */
     if (pchan->custom_tx) {
       pchan->custom_tx = BKE_pose_channel_find_name(outPose, pchan->custom_tx->name);
@@ -726,7 +738,7 @@ void BKE_pose_copy_data_ex(bPose **dst,
     pchan->draw_data = NULL; /* Drawing cache, no need to copy. */
 
     /* Runtime data, no need to copy. */
-    memset(&pchan->runtime, 0, sizeof(pchan->runtime));
+    BKE_pose_channel_runtime_reset_on_copy(&pchan->runtime);
   }
 
   /* for now, duplicate Bone Groups too when doing this */
@@ -956,6 +968,14 @@ void BKE_pose_channel_runtime_reset(bPoseChannel_Runtime *runtime)
   memset(runtime, 0, sizeof(*runtime));
 }
 
+/* Reset all non-persistent fields. */
+void BKE_pose_channel_runtime_reset_on_copy(bPoseChannel_Runtime *runtime)
+{
+  const SessionUUID uuid = runtime->session_uuid;
+  memset(runtime, 0, sizeof(*runtime));
+  runtime->session_uuid = uuid;
+}
+
 /** Deallocates runtime cache of a pose channel */
 void BKE_pose_channel_runtime_free(bPoseChannel_Runtime *runtime)
 {
@@ -1692,3 +1712,30 @@ void what_does_obaction(Object *ob,
     BKE_animsys_evaluate_animdata(&workob->id, &adt, anim_eval_context, ADT_RECALC_ANIM, false);
   }
 }
+
+void BKE_pose_check_uuids_unique_and_report(const bPose *pose)
+{
+  if (pose == NULL) {
+    return;
+  }
+
+  struct GSet *used_uuids = BLI_gset_new(
+      BLI_session_uuid_ghash_hash, BLI_session_uuid_ghash_compare, "sequencer used uuids");
+
+  LISTBASE_FOREACH (bPoseChannel *, pchan, &pose->chanbase) {
+    const SessionUUID *session_uuid = &pchan->runtime.session_uuid;
+    if (!BLI_session_uuid_is_generated(session_uuid)) {
+      printf("Pose channel %s does not have UUID generated.\n", pchan->name);
+      continue;
+    }
+
+    if (BLI_gset_lookup(used_uuids, session_uuid) != NULL) {
+      printf("Pose channel %s has duplicate UUID generated.\n", pchan->name);
+      continue;
+    }
+
+    BLI_gset_insert(used_uuids, (void *)session_uuid);
+  }
+
+  BLI_gset_free(used_uuids, NULL);
+}
diff --git a/source/blender/blenkernel/intern/armature.c b/source/blender/blenkernel/intern/armature.c
index c977ebe4ae2..631ce4edd20 100644
--- a/source/blender/blenkernel/intern/armature.c
+++ b/source/blender/blenkernel/intern/armature.c
@@ -2205,7 +2205,7 @@ static void pose_proxy_sync(Object *ob, Object *from, int layer_protected)
       pchan->mpath = NULL;
 
       /* Reset runtime data, we don't want to share that with the proxy. */
-      BKE_pose_channel_runtime_reset(&pchanw.runtime);
+      BKE_pose_channel_runtime_reset_on_copy(&pchanw.runtime);
 
       /* this is freed so copy a copy, else undo crashes */
       if (pchanw.prop) {
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 398598a3fb6..6d220d1fd1d 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -5145,6 +5145,9 @@ static void direct_link_pose(BlendDataReader *reader, bPose *pose)
   pose->chan_array = NULL;
 
   for (pchan = pose->chanbase.first; pchan; pchan = pchan->next) {
+    BKE_pose_channel_runtime_reset(&pchan->runtime);
+    BKE_pose_channel_session_uuid_generate(pchan);
+
     pchan->bone = NULL;
     BLO_read_data_address(reader, &pchan->parent);
     BLO_read_data_address(reader, &pchan->child);
@@ -5170,7 +5173,6 @@ static void direct_link_pose(BlendDataReader *reader, bPose *pose)
     CLAMP(pchan->rotmode, ROT_MODE_MIN, ROT_MODE_MAX);
 
     pchan->draw_data = NULL;
-    BKE_pose_channel_runtime_reset(&pchan->runtime);
   }
   pose->ikdata = NULL;
   if (pose->ikparam != NULL) {
diff --git a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc
index 9956391a2d7..89df41944e5 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc
+++ b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc
@@ -288,6 +288,14 @@ bool id_copy_inplace_no_main(const ID *id, ID *newid)
 {
   const ID *id_for_copy = id;
 
+  if (G.debug & G_DEBUG_DEPSGRAPH_UUID) {
+    const ID_Type id_type = GS(id_for_copy->name);
+    if (id_type == ID_OB) {
+      const Object *object = reinterpret_cast<const Object *>(id_for_copy);
+      BKE_pose_check_uuids_unique_and_report(object->pose);
+    }
+  }
+
 #ifdef NESTED_ID_NASTY_WORKAROUND
   NestedIDHackTempStorage id_hack_storage;
   id_for_copy = nested_id_hack_get_discarded_pointers(&id_hack_storage, id);
diff --git a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.cc b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.cc
index e0957a10cb1..88334e41192 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.cc
+++ b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.cc
@@ -85,11 +85,11 @@ void ObjectRuntimeBackup::backup_pose_channel_runtime_data(Object *object)
 {
   if (object->pose != nullptr) {
     LISTBASE_FOREACH (bPoseChannel *, pchan, &object->pose->chanbase) {
-      /* This is nullptr in Edit mode. */
-      if (pchan->orig_pchan != nullptr) {
-        pose_channel_runtime_data.add(pchan->orig_pchan, pchan->runtime);
-        BKE_pose_channel_runtime_reset(&pchan->runtime);
-      }
+      const SessionUUID &session_uuid = pchan->runtime.session_uuid;
+      BLI_assert(BLI_session_uuid_is_generated(&session_uuid));
+
+      pose_channel_runtime_data.add(session_uuid, pchan->runtime);
+      BKE_pose_channel_runtime_reset(&pchan->runtime);
     }
   }
 }
@@ -171,13 +171,10 @@ void ObjectRuntimeBackup::restore_pose_channel_runtime_data(Object *object)
 {
   if (object->pose != nullptr) {
     LISTBASE_FOREACH (bPoseChannel *, pchan, &object->pose->chanbase) {
-      /* This is nullptr in Edit mode. */
-      if (pchan->orig_pchan != nullptr) {
-        optional<bPoseChannel_Runtime> runtime = pose_channel_runtime_data.pop_try(
-            pchan->orig_pchan);
-        if (runtime.has_value()) {
-          pchan->runtime = *runtime;
-        }
+      const SessionUUID &session_uuid = pchan->runtime.session_uuid;
+      optional<bPoseChannel_Runtime> runtime = pose_channel_runtime_data.pop_try(session_uuid);
+      if (runtime.has_value()) {
+        pchan->runtime = *runtime;
       }
     }
   }
diff --git a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.h b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.h
index 04d7fb1bc22..a10f15634ce 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.h
+++ b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_object.h
@@ -24,6 +24,9 @@
 #pragma once
 
 #include "DNA_object_types.h"
+#include "DNA_session_uuid_types.h"
+
+#include "BLI_session_uuid.h"
 
 #include "intern/eval/deg_eval_runtime_backup_modifier.h"
 #include "intern/eval/deg_eval_runtime_backup_pose.h"
@@ -54,7 +57,7 @@ class ObjectRuntimeBackup {
   short base_flag;
   unsigned short base_local_view_bits;
   ModifierRuntimeDataBackup modifier_runtime_data;
-  Map<bPoseChannel *, bPoseChannel_Runtime> pose_channel_runtime_data;
+  Map<SessionUUID, bPoseChannel_Runtime> pose_channel_runtime_data;
 };
 
 }  // namespace deg
diff --git a/source/blender/editors/armature/armature_relations.c b/source/blender/editors/armature/armature_relations.c
index 0dd35fb9fdc..a737916e9a2 100644
--- a/source/blender/editors/armature/armature_relations.c
+++ b/source/blender/editors/armature/armature_relations.c
@@ -384,6 +384,7 @@ int ED_armature_join_objects_exec(bContext *C, wmOperator *op)
         BLI_remlink(curarm->edbo, curbone);
         BLI_addtail(arm->edbo, curbone);
 
+        /* Pose channel is moved from one storage to another, its UUID is still unique. */
         BLI_remlink(&opose->chanbase, pchan);
         BLI_addtail(&pose->chanbase, pchan);
         BKE_pose_channels_hash_free(opose);
diff --git a/source/blender/makesdna/DNA_action_types.h b/source/blender/makesdna/DNA_action_types.h
index 98e858dbf41..74293e25c5c 100644
--- a/source/blender/makesdna/DNA_action_types.h
+++ b/source/blender/makesdna/DNA_action_types.h
@@ -30,6 +30,7 @@
 
 #include "DNA_ID.h"
 #include "DNA_listBase.h"
+#include "DNA_session_uuid_types.h"
 #include "DNA_userdef_types.h" /* ThemeWireColor */
 #include "DNA_vec_types.h"
 #include "DNA_view2d_types.h"
@@ -188,6 +189,8 @@ struct DualQuat;
 struct Mat4;
 
 typedef struct bPoseChannel_Runtime {
+  SessionUUID session_uuid;
+
   /* Cached dual quaternion for deformation. */
   struct DualQuat deform_dual_quat;