[Bf-blender-cvs] [c7e7038] openvdb: Use tri-linear ("box") interpolation for OpenVDB grids rather than nearest point sampling.

[Lukas Tönne]

Commit: c7e7038edce55fd66f9ef3919cdf531e62afe99d
Author: Lukas Tönne
Date:   Wed Nov 16 17:05:04 2016 +0100
Branches: openvdb
https://developer.blender.org/rBc7e7038edce55fd66f9ef3919cdf531e62afe99d

Use tri-linear ("box") interpolation for OpenVDB grids rather than nearest point sampling.

Cycles shading options contain a setting for tri-cubic sampling as well, but this
is not supported in OpenVDB by default (only tri-quadratic). Cubic sampling appears
a bit pointless anyway, compared to the ability to add actual geometric detail.

===================================================================

M	intern/cycles/kernel/geom/geom_volume.h
M	intern/cycles/kernel/openvdb/vdb_thread.cpp

===================================================================

diff --git a/intern/cycles/kernel/geom/geom_volume.h b/intern/cycles/kernel/geom/geom_volume.h
index 351df44..28ea80f 100644
--- a/intern/cycles/kernel/geom/geom_volume.h
+++ b/intern/cycles/kernel/geom/geom_volume.h
@@ -86,7 +86,13 @@ ccl_device float volume_attribute_float(KernelGlobals *kg, const ShaderData *sd,
 
 #if 1 /* XXX WITH_OPENVDB ? */
 	float3 P = ccl_fetch(sd, P);
-	r = kernel_tex_voxel_float(desc.offset, P.x, P.y, P.z, OPENVDB_SAMPLE_POINT);
+	/* XXX OpenVDB does not support cubic interpolation (could use quadratic though) - lukas_t */
+#if 0
+	if(sd->flag & SD_VOLUME_CUBIC)
+		r = kernel_tex_voxel_float(desc.offset, P.x, P.y, P.z, ...)
+	else
+#endif
+		r = kernel_tex_voxel_float(desc.offset, P.x, P.y, P.z, OPENVDB_SAMPLE_BOX);
 #else
 	float3 P = volume_normalized_position(kg, sd, ccl_fetch(sd, P));
 	if(sd->flag & SD_VOLUME_CUBIC)
diff --git a/intern/cycles/kernel/openvdb/vdb_thread.cpp b/intern/cycles/kernel/openvdb/vdb_thread.cpp
index 5a65dc9..57c57f9 100644
--- a/intern/cycles/kernel/openvdb/vdb_thread.cpp
+++ b/intern/cycles/kernel/openvdb/vdb_thread.cpp
@@ -146,10 +146,14 @@ float vdb_volume_sample_scalar(OpenVDBGlobals */*vdb*/, OpenVDBThreadData *vdb_t
 {
 	OpenVDBScalarThreadData &data = vdb_thread->scalar_data[vdb_index];
 	
-	if (sampling == OPENVDB_SAMPLE_POINT)
-		return data.point_sampler->wsSample(openvdb::Vec3d(x, y, z));
-	else
-		return data.box_sampler->wsSample(openvdb::Vec3d(x, y, z));
+	switch (sampling) {
+		case OPENVDB_SAMPLE_POINT:
+			return data.point_sampler->wsSample(openvdb::Vec3d(x, y, z));
+		case OPENVDB_SAMPLE_BOX:
+			return data.box_sampler->wsSample(openvdb::Vec3d(x, y, z));
+	}
+	
+	return 0.0f;
 }
 
 float3 vdb_volume_sample_vector(OpenVDBGlobals *vdb, OpenVDBThreadData *vdb_thread, int vdb_index,
@@ -160,16 +164,24 @@ float3 vdb_volume_sample_vector(OpenVDBGlobals *vdb, OpenVDBThreadData *vdb_thre
 	openvdb::Vec3s r;
 	
 	if (staggered) {
-		if (sampling == OPENVDB_SAMPLE_POINT)
-			r = data.stag_point_sampler->wsSample(openvdb::Vec3d(x, y, z));
-		else
-			r = data.stag_box_sampler->wsSample(openvdb::Vec3d(x, y, z));
+		switch (sampling) {
+			case OPENVDB_SAMPLE_POINT:
+				r = data.stag_point_sampler->wsSample(openvdb::Vec3d(x, y, z));
+				break;
+			case OPENVDB_SAMPLE_BOX:
+				r = data.stag_box_sampler->wsSample(openvdb::Vec3d(x, y, z));
+				break;
+		}
 	}
 	else {
-		if (sampling == OPENVDB_SAMPLE_POINT)
-			r = data.point_sampler->wsSample(openvdb::Vec3d(x, y, z));
-		else
-			r = data.box_sampler->wsSample(openvdb::Vec3d(x, y, z));
+		switch (sampling) {
+			case OPENVDB_SAMPLE_POINT:
+				r = data.point_sampler->wsSample(openvdb::Vec3d(x, y, z));
+				break;
+			case OPENVDB_SAMPLE_BOX:
+				r = data.box_sampler->wsSample(openvdb::Vec3d(x, y, z));
+				break;
+		}
 	}
 	
 	return make_float3(r.x(), r.y(), r.z());