Cycles: Add missing velocity attribute to builtin image loader

For some reason other parts of blender importer were assuming velocity
is supported, but actual loader was not aware of that.

Fixes T48064: Adding velocity attribute crashes render

1 files changed, 15 insertions, 0 deletions

diff --git a/intern/cycles/blender/blender_session.cpp b/intern/cycles/blender/blender_session.cpp
index aac2ffb7474..7dfe94127e9 100644
--- a/intern/cycles/blender/blender_session.cpp
+++ b/intern/cycles/blender/blender_session.cpp
@@ -1117,6 +1117,8 @@ void BlenderSession::builtin_image_info(const string &builtin_name, void *builti
 			channels = 1;
 		else if(builtin_name == Attribute::standard_name(ATTR_STD_VOLUME_COLOR))
 			channels = 4;
+		else if(builtin_name == Attribute::standard_name(ATTR_STD_VOLUME_VELOCITY))
+			channels = 3;
 		else
 			return;
 
@@ -1246,6 +1248,11 @@ bool BlenderSession::builtin_image_float_pixels(const string &builtin_name, void
 		int3 resolution = get_int3(b_domain.domain_resolution());
 		int length, amplify = (b_domain.use_high_resolution())? b_domain.amplify() + 1: 1;
 
+		/* Velocity data is always low-resolution. */
+		if(builtin_name == Attribute::standard_name(ATTR_STD_VOLUME_VELOCITY)) {
+			amplify = 1;
+		}
+
 		int width = resolution.x * amplify;
 		int height = resolution.y * amplify;
 		int depth = resolution.z * amplify;
@@ -1278,6 +1285,14 @@ bool BlenderSession::builtin_image_float_pixels(const string &builtin_name, void
 				return true;
 			}
 		}
+		else if(builtin_name == Attribute::standard_name(ATTR_STD_VOLUME_VELOCITY)) {
+			SmokeDomainSettings_velocity_grid_get_length(&b_domain.ptr, &length);
+
+			if(length == num_pixels*3) {
+				SmokeDomainSettings_velocity_grid_get(&b_domain.ptr, pixels);
+				return true;
+			}
+		}
 		else {
 			fprintf(stderr, "Cycles error: unknown volume attribute, skipping\n");
 			pixels[0] = 0.0f;