Cycles: Enabled quaternion motion blur with Embree.

Bringing Embree's motion blur closer to Cycles' native blur.
This requries Embree 3.8.0 or newer.

Differential Revision: https://developer.blender.org/D6575

6 files changed, 21 insertions, 39 deletions

diff --git a/build_files/cmake/platform/platform_apple.cmake b/build_files/cmake/platform/platform_apple.cmake
index b231a2b6fa4..e997f105324 100644
--- a/build_files/cmake/platform/platform_apple.cmake
+++ b/build_files/cmake/platform/platform_apple.cmake
@@ -381,7 +381,7 @@ if(WITH_CYCLES_OSL)
 endif()
 
 if(WITH_CYCLES_EMBREE)
-  find_package(Embree 3.2.4 REQUIRED)
+  find_package(Embree 3.8.0 REQUIRED)
   set(PLATFORM_LINKFLAGS "${PLATFORM_LINKFLAGS} -Xlinker -stack_size -Xlinker 0x100000")
 endif()
 
diff --git a/build_files/cmake/platform/platform_unix.cmake b/build_files/cmake/platform/platform_unix.cmake
index 91f836d5265..ac570f17e47 100644
--- a/build_files/cmake/platform/platform_unix.cmake
+++ b/build_files/cmake/platform/platform_unix.cmake
@@ -393,7 +393,7 @@ if(WITH_OPENCOLORIO)
 endif()
 
 if(WITH_CYCLES_EMBREE)
-  find_package(Embree 3.2.4 REQUIRED)
+  find_package(Embree 3.8.0 REQUIRED)
 endif()
 
 if(WITH_OPENIMAGEDENOISE)
diff --git a/intern/cycles/bvh/bvh_embree.cpp b/intern/cycles/bvh/bvh_embree.cpp
index 851fdad7842..35c1b463b49 100644
--- a/intern/cycles/bvh/bvh_embree.cpp
+++ b/intern/cycles/bvh/bvh_embree.cpp
@@ -563,9 +563,20 @@ void BVHEmbree::add_instance(Object *ob, int i)
   rtcSetGeometryTimeStepCount(geom_id, num_motion_steps);
 
   if (ob->use_motion()) {
+    array<DecomposedTransform> decomp(ob->motion.size());
+    transform_motion_decompose(decomp.data(), ob->motion.data(), ob->motion.size());
     for (size_t step = 0; step < num_motion_steps; ++step) {
-      rtcSetGeometryTransform(
-          geom_id, step, RTC_FORMAT_FLOAT3X4_ROW_MAJOR, (const float *)&ob->motion[step]);
+      RTCQuaternionDecomposition rtc_decomp;
+      rtcInitQuaternionDecomposition(&rtc_decomp);
+      rtcQuaternionDecompositionSetQuaternion(
+          &rtc_decomp, decomp[step].x.w, decomp[step].x.x, decomp[step].x.y, decomp[step].x.z);
+      rtcQuaternionDecompositionSetScale(
+          &rtc_decomp, decomp[step].y.w, decomp[step].z.w, decomp[step].w.w);
+      rtcQuaternionDecompositionSetTranslation(
+          &rtc_decomp, decomp[step].y.x, decomp[step].y.y, decomp[step].y.z);
+      rtcQuaternionDecompositionSetSkew(
+          &rtc_decomp, decomp[step].z.x, decomp[step].z.y, decomp[step].w.x);
+      rtcSetGeometryTransformQuaternion(geom_id, step, &rtc_decomp);
     }
   }
   else {
diff --git a/intern/cycles/cmake/external_libs.cmake b/intern/cycles/cmake/external_libs.cmake
index 5bf681792ca..0b082b11cf7 100644
--- a/intern/cycles/cmake/external_libs.cmake
+++ b/intern/cycles/cmake/external_libs.cmake
@@ -135,7 +135,7 @@ if(CYCLES_STANDALONE_REPOSITORY)
   ####
   # embree
   if(WITH_CYCLES_EMBREE)
-    find_package(embree 3.2.4 REQUIRED)
+    find_package(embree 3.8.0 REQUIRED)
   endif()
 
   ####
diff --git a/intern/cycles/kernel/geom/geom_object.h b/intern/cycles/kernel/geom/geom_object.h
index af4e6fbd89b..ac2ddf575ca 100644
--- a/intern/cycles/kernel/geom/geom_object.h
+++ b/intern/cycles/kernel/geom/geom_object.h
@@ -81,13 +81,7 @@ ccl_device_inline Transform object_fetch_transform_motion(KernelGlobals *kg,
   const uint num_steps = kernel_tex_fetch(__objects, object).numsteps * 2 + 1;
 
   Transform tfm;
-#  ifdef __EMBREE__
-  if (kernel_data.bvh.scene) {
-    transform_motion_array_interpolate_straight(&tfm, motion, num_steps, time);
-  }
-  else
-#  endif
-    transform_motion_array_interpolate(&tfm, motion, num_steps, time);
+  transform_motion_array_interpolate(&tfm, motion, num_steps, time);
 
   return tfm;
 }
diff --git a/intern/cycles/util/util_transform.h b/intern/cycles/util/util_transform.h
index 407654245cb..d0a6264d5cf 100644
--- a/intern/cycles/util/util_transform.h
+++ b/intern/cycles/util/util_transform.h
@@ -344,10 +344,10 @@ ccl_device_inline Transform transform_empty()
 
 ccl_device_inline float4 quat_interpolate(float4 q1, float4 q2, float t)
 {
-  /* use simpe nlerp instead of slerp. it's faster and almost the same */
+  /* Optix is using lerp to interpolate motion transformations. */
+#ifdef __KERNEL_OPTIX__
   return normalize((1.0f - t) * q1 + t * q2);
-
-#if 0
+#else  /* __KERNEL_OPTIX__ */
   /* note: this does not ensure rotation around shortest angle, q1 and q2
    * are assumed to be matched already in transform_motion_decompose */
   float costheta = dot(q1, q2);
@@ -365,7 +365,7 @@ ccl_device_inline float4 quat_interpolate(float4 q1, float4 q2, float t)
     float thetap = theta * t;
     return q1 * cosf(thetap) + qperp * sinf(thetap);
   }
-#endif
+#endif /* __KERNEL_OPTIX__ */
 }
 
 ccl_device_inline Transform transform_quick_inverse(Transform M)
@@ -468,29 +468,6 @@ ccl_device void transform_motion_array_interpolate(Transform *tfm,
 
 #ifndef __KERNEL_GPU__
 
-#  ifdef WITH_EMBREE
-ccl_device void transform_motion_array_interpolate_straight(
-    Transform *tfm, const ccl_global DecomposedTransform *motion, uint numsteps, float time)
-{
-  /* Figure out which steps we need to interpolate. */
-  int maxstep = numsteps - 1;
-  int step = min((int)(time * maxstep), maxstep - 1);
-  float t = time * maxstep - step;
-
-  const ccl_global DecomposedTransform *a = motion + step;
-  const ccl_global DecomposedTransform *b = motion + step + 1;
-  Transform step1, step2;
-
-  transform_compose(&step1, a);
-  transform_compose(&step2, b);
-
-  /* matrix lerp */
-  tfm->x = (1.0f - t) * step1.x + t * step2.x;
-  tfm->y = (1.0f - t) * step1.y + t * step2.y;
-  tfm->z = (1.0f - t) * step1.z + t * step2.z;
-}
-#  endif
-
 class BoundBox2D;
 
 ccl_device_inline bool operator==(const DecomposedTransform &A, const DecomposedTransform &B)