Cycles: Added Embree as BVH option for CPU renders.

Note that this is turned off by default and must be enabled at build time with the CMake WITH_CYCLES_EMBREE flag.
Embree must be built as a static library with ray masking turned on, the `make deps` scripts have been updated accordingly.
There, Embree is off by default too and must be enabled with the WITH_EMBREE flag.

Using Embree allows for much faster rendering of deformation motion blur while reducing the memory footprint.

TODO: GPU implementation, deduplication of data, leveraging more of Embrees features (e.g. tessellation cache).

Differential Revision: https://developer.blender.org/D3682

1 files changed, 20 insertions, 0 deletions

diff --git a/intern/cycles/util/util_transform.h b/intern/cycles/util/util_transform.h
index e781f85dded..d3bfb1d5752 100644
--- a/intern/cycles/util/util_transform.h
+++ b/intern/cycles/util/util_transform.h
@@ -422,6 +422,26 @@ ccl_device void transform_motion_array_interpolate(Transform *tfm,
 	transform_compose(tfm, &decomp);
 }
 
+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;
+}
+
 #ifndef __KERNEL_GPU__
 
 class BoundBox2D;