Cycles: add Vector Displacement node and extend Displacement node.

This adds midlevel and object/world space for displacement, and a
vector displacement node with tangent/object/world space, midlevel
and scale.

Note that tangent space vector displacement still is not exactly
compatible with maps created by other software, this will require
changes to the tangent computation.

Differential Revision: https://developer.blender.org/D1734

3 files changed, 64 insertions, 5 deletions

diff --git a/intern/cycles/kernel/svm/svm.h b/intern/cycles/kernel/svm/svm.h
index cbc603d4645..a8f99d23b7d 100644
--- a/intern/cycles/kernel/svm/svm.h
+++ b/intern/cycles/kernel/svm/svm.h
@@ -270,6 +270,9 @@ ccl_device_noinline void svm_eval_nodes(KernelGlobals *kg, ShaderData *sd, ccl_a
 			case NODE_DISPLACEMENT:
 				svm_node_displacement(kg, sd, stack, node);
 				break;
+			case NODE_VECTOR_DISPLACEMENT:
+				svm_node_vector_displacement(kg, sd, stack, node, &offset);
+				break;
 #  endif  /* NODES_FEATURE(NODE_FEATURE_BUMP) */
 #  ifdef __TEXTURES__
 			case NODE_TEX_IMAGE:
diff --git a/intern/cycles/kernel/svm/svm_displace.h b/intern/cycles/kernel/svm/svm_displace.h
index 3066a364684..b9fd5bbf84d 100644
--- a/intern/cycles/kernel/svm/svm_displace.h
+++ b/intern/cycles/kernel/svm/svm_displace.h
@@ -89,17 +89,72 @@ ccl_device void svm_node_set_displacement(KernelGlobals *kg, ShaderData *sd, flo
 
 ccl_device void svm_node_displacement(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node)
 {
-	uint height_offset, scale_offset, normal_offset, displacement_offset;
-	decode_node_uchar4(node.y, &height_offset, &scale_offset, &normal_offset, &displacement_offset);
+	uint height_offset, midlevel_offset, scale_offset, normal_offset;
+	decode_node_uchar4(node.y, &height_offset, &midlevel_offset, &scale_offset, &normal_offset);
 
 	float height = stack_load_float(stack, height_offset);
+	float midlevel = stack_load_float(stack, midlevel_offset);
 	float scale = stack_load_float(stack, scale_offset);
 	float3 normal = stack_valid(normal_offset)? stack_load_float3(stack, normal_offset): sd->N;
+	uint space = node.w;
 
 	float3 dP = normal;
-	object_inverse_normal_transform(kg, sd, &dP);
-	dP *= height * scale;
-	object_dir_transform(kg, sd, &dP);
+
+	if(space == NODE_NORMAL_MAP_OBJECT) {
+		/* Object space. */
+		object_inverse_normal_transform(kg, sd, &dP);
+		dP *= (height - midlevel) * scale;
+		object_dir_transform(kg, sd, &dP);
+	}
+	else {
+		/* World space. */
+		dP *= (height - midlevel) * scale;
+	}
+
+	stack_store_float3(stack, node.z, dP);
+}
+
+ccl_device void svm_node_vector_displacement(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, int *offset)
+{
+	uint4 data_node = read_node(kg, offset);
+	uint space = data_node.x;
+
+	uint vector_offset, midlevel_offset,scale_offset, displacement_offset;
+	decode_node_uchar4(node.y, &vector_offset, &midlevel_offset, &scale_offset, &displacement_offset);
+
+	float3 vector = stack_load_float3(stack, vector_offset);
+	float midlevel = stack_load_float(stack, midlevel_offset);
+	float scale = stack_load_float(stack, scale_offset);
+	float3 dP = (vector - make_float3(midlevel, midlevel, midlevel)) * scale;
+
+	if(space == NODE_NORMAL_MAP_TANGENT) {
+		/* Tangent space. */
+		float3 normal = sd->N;
+		object_inverse_normal_transform(kg, sd, &normal);
+
+		const AttributeDescriptor attr = find_attribute(kg, sd, node.z);
+		float3 tangent;
+		if(attr.offset != ATTR_STD_NOT_FOUND) {
+			tangent = primitive_attribute_float3(kg, sd, attr, NULL, NULL);
+		}
+		else {
+			tangent = normalize(sd->dPdu);
+		}
+
+		float3 bitangent = normalize(cross(normal, tangent));;
+		const AttributeDescriptor attr_sign = find_attribute(kg, sd, node.w);
+		if(attr_sign.offset != ATTR_STD_NOT_FOUND) {
+			float sign = primitive_attribute_float(kg, sd, attr_sign, NULL, NULL);
+			bitangent *= sign;
+		}
+
+		dP = tangent*dP.x + normal*dP.y + bitangent*dP.z;
+	}
+
+	if(space != NODE_NORMAL_MAP_WORLD) {
+		/* Tangent or object space. */
+		object_dir_transform(kg, sd, &dP);
+	}
 
 	stack_store_float3(stack, displacement_offset, dP);
 }
diff --git a/intern/cycles/kernel/svm/svm_types.h b/intern/cycles/kernel/svm/svm_types.h
index 00c7752da8c..6ff04a65462 100644
--- a/intern/cycles/kernel/svm/svm_types.h
+++ b/intern/cycles/kernel/svm/svm_types.h
@@ -134,6 +134,7 @@ typedef enum ShaderNodeType {
 	NODE_LEAVE_BUMP_EVAL,
 	NODE_BEVEL,
 	NODE_DISPLACEMENT,
+	NODE_VECTOR_DISPLACEMENT,
 } ShaderNodeType;
 
 typedef enum NodeAttributeType {