Merge branch 'blender-v2.90-release'

5 files changed, 108 insertions, 3 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;