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

6 files changed, 74 insertions, 21 deletions

diff --git a/intern/cycles/blender/addon/version_update.py b/intern/cycles/blender/addon/version_update.py
index efd794461d6..26cdecd2d52 100644
--- a/intern/cycles/blender/addon/version_update.py
+++ b/intern/cycles/blender/addon/version_update.py
@@ -89,6 +89,47 @@ def foreach_cycles_node(callback):
                                     traversed)
 
 
+def displacement_node_insert(material, nodetree, traversed):
+    if nodetree in traversed:
+        return
+    traversed.add(nodetree)
+
+    for node in nodetree.nodes:
+        if node.bl_idname == 'ShaderNodeGroup':
+            displacement_node_insert(material, node.node_tree, traversed)
+
+    # Gather links to replace
+    displacement_links = []
+    for link in nodetree.links:
+        if link.to_node.bl_idname == 'ShaderNodeOutputMaterial' and \
+           link.from_node.bl_idname != 'ShaderNodeDisplacement' and \
+           link.to_socket.identifier == 'Displacement':
+           displacement_links.append(link)
+
+    # Replace links with displacement node
+    for link in displacement_links:
+        from_node = link.from_node
+        from_socket = link.from_socket
+        to_node = link.to_node
+        to_socket = link.to_socket
+
+        nodetree.links.remove(link)
+
+        node = nodetree.nodes.new(type='ShaderNodeDisplacement')
+        node.location[0] = 0.5 * (from_node.location[0] + to_node.location[0]);
+        node.location[1] = 0.5 * (from_node.location[1] + to_node.location[1]);
+        node.inputs['Scale'].default_value = 0.1
+
+        nodetree.links.new(from_socket, node.inputs['Height'])
+        nodetree.links.new(node.outputs['Displacement'], to_socket)
+
+def displacement_nodes_insert():
+    traversed = set()
+    for material in bpy.data.materials:
+        if check_is_new_shading_material(material):
+            displacement_node_insert(material, material.node_tree, traversed)
+
+
 def mapping_node_order_flip(node):
     """
     Flip euler order of mapping shader node
@@ -315,3 +356,6 @@ def do_versions(self):
                 cscene.blur_glossy = 0.0
             if not cscene.is_property_set("sample_clamp_indirect"):
                 cscene.sample_clamp_indirect = 0.0
+
+    if bpy.data.version <= (2, 79, 1):
+        displacement_nodes_insert()
diff --git a/intern/cycles/kernel/shaders/node_output_displacement.osl b/intern/cycles/kernel/shaders/node_output_displacement.osl
index 294b8dd6bf2..5dbef0244fe 100644
--- a/intern/cycles/kernel/shaders/node_output_displacement.osl
+++ b/intern/cycles/kernel/shaders/node_output_displacement.osl
@@ -16,10 +16,8 @@
 
 #include "stdosl.h"
 
-displacement node_output_displacement(float Displacement = 0.0)
+displacement node_output_displacement(vector Displacement = 0.0)
 {
-	vector dP = normalize(transform("object", N));
-	dP *= Displacement * 0.1; /* todo: get rid of this factor */
-	P += transform("object", "world", dP);
+	P += Displacement;
 }
 
diff --git a/intern/cycles/kernel/svm/svm_displace.h b/intern/cycles/kernel/svm/svm_displace.h
index 1ac2c8fd52e..3066a364684 100644
--- a/intern/cycles/kernel/svm/svm_displace.h
+++ b/intern/cycles/kernel/svm/svm_displace.h
@@ -83,15 +83,7 @@ ccl_device void svm_node_set_bump(KernelGlobals *kg, ShaderData *sd, float *stac
 
 ccl_device void svm_node_set_displacement(KernelGlobals *kg, ShaderData *sd, float *stack, uint fac_offset)
 {
-	float d = stack_load_float(stack, fac_offset);
-
-	float3 dP = sd->N;
-	object_inverse_normal_transform(kg, sd, &dP);
-
-	dP *= d*0.1f; /* todo: get rid of this factor */
-
-	object_dir_transform(kg, sd, &dP);
-
+	float3 dP = stack_load_float3(stack, fac_offset);
 	sd->P += dP;
 }
 
diff --git a/intern/cycles/render/graph.cpp b/intern/cycles/render/graph.cpp
index 56434b39da5..fb2e34c2fc7 100644
--- a/intern/cycles/render/graph.cpp
+++ b/intern/cycles/render/graph.cpp
@@ -526,10 +526,10 @@ void ShaderGraph::constant_fold()
 	 * that happens to ensure there is still a valid graph for displacement.
 	 */
 	if(has_displacement && !output()->input("Displacement")->link) {
-		ValueNode *value = (ValueNode*)add(new ValueNode());
+		ColorNode *value = (ColorNode*)add(new ColorNode());
 		value->value = output()->displacement;
 
-		connect(value->output("Value"), output()->input("Displacement"));
+		connect(value->output("Color"), output()->input("Displacement"));
 	}
 }
 
@@ -861,7 +861,7 @@ void ShaderGraph::bump_from_displacement(bool use_object_space)
 
 	if(!displacement_in->link)
 		return;
-	
+
 	/* find dependencies for the given input */
 	ShaderNodeSet nodes_displace;
 	find_dependencies(nodes_displace, displacement_in);
@@ -893,15 +893,34 @@ void ShaderGraph::bump_from_displacement(bool use_object_space)
 	/* add bump node and connect copied graphs to it */
 	BumpNode *bump = (BumpNode*)add(new BumpNode());
 	bump->use_object_space = use_object_space;
+	bump->distance = 1.0f;
 
 	ShaderOutput *out = displacement_in->link;
 	ShaderOutput *out_center = nodes_center[out->parent]->output(out->name());
 	ShaderOutput *out_dx = nodes_dx[out->parent]->output(out->name());
 	ShaderOutput *out_dy = nodes_dy[out->parent]->output(out->name());
 
-	connect(out_center, bump->input("SampleCenter"));
-	connect(out_dx, bump->input("SampleX"));
-	connect(out_dy, bump->input("SampleY"));
+	/* convert displacement vector to height */
+	VectorMathNode *dot_center = (VectorMathNode*)add(new VectorMathNode());
+	VectorMathNode *dot_dx = (VectorMathNode*)add(new VectorMathNode());
+	VectorMathNode *dot_dy = (VectorMathNode*)add(new VectorMathNode());
+
+	dot_center->type = NODE_VECTOR_MATH_DOT_PRODUCT;
+	dot_dx->type = NODE_VECTOR_MATH_DOT_PRODUCT;
+	dot_dy->type = NODE_VECTOR_MATH_DOT_PRODUCT;
+
+	GeometryNode *geom = (GeometryNode*)add(new GeometryNode());
+	connect(geom->output("Normal"), dot_center->input("Vector2"));
+	connect(geom->output("Normal"), dot_dx->input("Vector2"));
+	connect(geom->output("Normal"), dot_dy->input("Vector2"));
+
+	connect(out_center, dot_center->input("Vector1"));
+	connect(out_dx, dot_dx->input("Vector1"));
+	connect(out_dy, dot_dy->input("Vector1"));
+
+	connect(dot_center->output("Value"), bump->input("SampleCenter"));
+	connect(dot_dx->output("Value"), bump->input("SampleX"));
+	connect(dot_dy->output("Value"), bump->input("SampleY"));
 	
 	/* connect the bump out to the set normal in: */
 	connect(bump->output("Normal"), set_normal->input("Direction"));
diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 87e8ec3d3cc..14c0dbab9f3 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -4780,7 +4780,7 @@ NODE_DEFINE(OutputNode)
 
 	SOCKET_IN_CLOSURE(surface, "Surface");
 	SOCKET_IN_CLOSURE(volume, "Volume");
-	SOCKET_IN_FLOAT(displacement, "Displacement", 0.0f);
+	SOCKET_IN_VECTOR(displacement, "Displacement", make_float3(0.0f, 0.0f, 0.0f));
 	SOCKET_IN_NORMAL(normal, "Normal", make_float3(0.0f, 0.0f, 0.0f));
 
 	return type;
diff --git a/intern/cycles/render/nodes.h b/intern/cycles/render/nodes.h
index d1f32bbf491..578451cbcfa 100644
--- a/intern/cycles/render/nodes.h
+++ b/intern/cycles/render/nodes.h
@@ -154,7 +154,7 @@ public:
 
 	void *surface;
 	void *volume;
-	float displacement;
+	float3 displacement;
 	float3 normal;
 
 	/* Don't allow output node de-duplication. */