Cycles volume: fast empty space optimization by generating a tight mesh

around the volume.

We generate a tight mesh around the active voxels of the volume in order
to effectively skip empty space, and start volume ray marching as close
to interesting volume data as possible. See code comments for details on
how the mesh generation algorithm works.

This gives up to 2x speedups in some scenes.

Reviewed by: brecht, dingto

Reviewers: #cycles

Subscribers: lvxejay, jtheninja, brecht

Differential Revision: https://developer.blender.org/D3038

1 files changed, 16 insertions, 0 deletions

diff --git a/intern/cycles/util/util_math_int3.h b/intern/cycles/util/util_math_int3.h
index fa7a02636de..1bc6ca7f376 100644
--- a/intern/cycles/util/util_math_int3.h
+++ b/intern/cycles/util/util_math_int3.h
@@ -78,6 +78,22 @@ ccl_device_inline int3 clamp(const int3& a, int3& mn, int mx)
 }
 #endif  /* !__KERNEL_OPENCL__ */
 
+
+ccl_device_inline bool operator==(const int3 &a, const int3 &b)
+{
+	return a.x == b.x && a.y == b.y && a.z == b.z;
+}
+
+ccl_device_inline bool operator!=(const int3 &a, const int3 &b)
+{
+	return !(a == b);
+}
+
+ccl_device_inline bool operator<(const int3 &a, const int3 &b)
+{
+	return a.x < b.x && a.y < b.y && a.z < b.z;
+}
+
 CCL_NAMESPACE_END
 
 #endif /* __UTIL_MATH_INT3_H__ */