Cycles: change material output displacement to vector.

Previously only scalar displacement along the normal was supported,
now displacement can go in any direction. For backwards compatibility,
a Displacement node will be automatically inserted in existing files.

This will make it possible to support vector displacement maps in the
future. It's already possible to use them to some extent, but requires
a manual shader node setup. For tangent space maps the right tangent
may also not be available yet, depends on the map.

Differential Revision: https://developer.blender.org/D3015

2 files changed, 16 insertions, 1 deletions

diff --git a/source/blender/nodes/shader/node_shader_tree.c b/source/blender/nodes/shader/node_shader_tree.c
index b4cdb158526..8fa074c5cb7 100644
--- a/source/blender/nodes/shader/node_shader_tree.c
+++ b/source/blender/nodes/shader/node_shader_tree.c
@@ -449,6 +449,21 @@ static void ntree_shader_relink_displacement(bNodeTree *ntree,
 	 * cycles in the Cycles material :)
 	 */
 	nodeRemLink(ntree, displacement_link);
+
+	/* Convert displacement vector to bump height. */
+	bNode *dot_node = nodeAddStaticNode(NULL, ntree, SH_NODE_VECT_MATH);
+	bNode *geo_node = nodeAddStaticNode(NULL, ntree, SH_NODE_NEW_GEOMETRY);
+	dot_node->custom1 = 3; /* dot product */
+
+	nodeAddLink(ntree,
+	            displacement_node, displacement_socket,
+	            dot_node, dot_node->inputs.first);
+	nodeAddLink(ntree,
+	            geo_node, ntree_shader_node_find_output(geo_node, "Normal"),
+	            dot_node, dot_node->inputs.last);
+	displacement_node = dot_node;
+	displacement_socket = ntree_shader_node_find_output(dot_node, "Value");
+
 	/* We can't connect displacement to normal directly, use bump node for that
 	 * and hope that it gives good enough approximation.
 	 */
diff --git a/source/blender/nodes/shader/nodes/node_shader_output_material.c b/source/blender/nodes/shader/nodes/node_shader_output_material.c
index 336536b21ee..aeb8b546eed 100644
--- a/source/blender/nodes/shader/nodes/node_shader_output_material.c
+++ b/source/blender/nodes/shader/nodes/node_shader_output_material.c
@@ -32,7 +32,7 @@
 static bNodeSocketTemplate sh_node_output_material_in[] = {
 	{	SOCK_SHADER, 1, N_("Surface")},
 	{	SOCK_SHADER, 1, N_("Volume")},
-	{	SOCK_FLOAT, 1, N_("Displacement"),	0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
+	{	SOCK_VECTOR, 1, N_("Displacement"),	0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
 	{	-1, 0, ""	}
 };