Cycles: support for custom shader AOVs

Custom render passes are added in the Shader AOVs panel in the view layer
settings, with a name and data type. In shader nodes, an AOV Output node
is then used to output either a value or color to the pass.

Arbitrary names can be used for these passes, as long as they don't conflict
with built-in passes that are enabled. The AOV Output node can be used in both
material and world shader nodes.

Implemented by Lukas, with tweaks by Brecht.

Differential Revision: https://developer.blender.org/D4837

3 files changed, 65 insertions, 0 deletions

diff --git a/intern/cycles/kernel/svm/svm.h b/intern/cycles/kernel/svm/svm.h
index 18f086d6726..c4d7164a4d8 100644
--- a/intern/cycles/kernel/svm/svm.h
+++ b/intern/cycles/kernel/svm/svm.h
@@ -164,6 +164,7 @@ CCL_NAMESPACE_END
 #include "kernel/svm/svm_math_util.h"
 #include "kernel/svm/svm_mapping_util.h"
 
+#include "kernel/svm/svm_aov.h"
 #include "kernel/svm/svm_attribute.h"
 #include "kernel/svm/svm_gradient.h"
 #include "kernel/svm/svm_blackbody.h"
@@ -218,6 +219,7 @@ CCL_NAMESPACE_BEGIN
 ccl_device_noinline void svm_eval_nodes(KernelGlobals *kg,
                                         ShaderData *sd,
                                         ccl_addr_space PathState *state,
+                                        ccl_global float *buffer,
                                         ShaderType type,
                                         int path_flag)
 {
@@ -467,6 +469,17 @@ ccl_device_noinline void svm_eval_nodes(KernelGlobals *kg,
       case NODE_IES:
         svm_node_ies(kg, sd, stack, node, &offset);
         break;
+      case NODE_AOV_START:
+        if (!svm_node_aov_check(state, buffer)) {
+          return;
+        }
+        break;
+      case NODE_AOV_COLOR:
+        svm_node_aov_color(kg, sd, stack, node, buffer);
+        break;
+      case NODE_AOV_VALUE:
+        svm_node_aov_value(kg, sd, stack, node, buffer);
+        break;
 #  endif /* __EXTRA_NODES__ */
 #endif   /* NODES_GROUP(NODE_GROUP_LEVEL_2) */
 
diff --git a/intern/cycles/kernel/svm/svm_aov.h b/intern/cycles/kernel/svm/svm_aov.h
new file mode 100644
index 00000000000..899e466d099
--- /dev/null
+++ b/intern/cycles/kernel/svm/svm_aov.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2011-2013 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+CCL_NAMESPACE_BEGIN
+
+ccl_device_inline bool svm_node_aov_check(ccl_addr_space PathState *state,
+                                          ccl_global float *buffer)
+{
+  int path_flag = state->flag;
+
+  bool is_primary = (path_flag & PATH_RAY_CAMERA) && (!(path_flag & PATH_RAY_SINGLE_PASS_DONE));
+
+  return ((buffer != NULL) && is_primary);
+}
+
+ccl_device void svm_node_aov_color(
+    KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, ccl_global float *buffer)
+{
+  float3 val = stack_load_float3(stack, node.y);
+
+  if (buffer) {
+    kernel_write_pass_float4(buffer + kernel_data.film.pass_aov_color + 4 * node.z,
+                             make_float4(val.x, val.y, val.z, 1.0f));
+  }
+}
+
+ccl_device void svm_node_aov_value(
+    KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, ccl_global float *buffer)
+{
+  float val = stack_load_float(stack, node.y);
+
+  if (buffer) {
+    kernel_write_pass_float(buffer + kernel_data.film.pass_aov_value + node.z, val);
+  }
+}
+CCL_NAMESPACE_END
diff --git a/intern/cycles/kernel/svm/svm_types.h b/intern/cycles/kernel/svm/svm_types.h
index 040e7c6a0f8..8dbb147e76a 100644
--- a/intern/cycles/kernel/svm/svm_types.h
+++ b/intern/cycles/kernel/svm/svm_types.h
@@ -150,6 +150,9 @@ typedef enum ShaderNodeType {
   NODE_VERTEX_COLOR,
   NODE_VERTEX_COLOR_BUMP_DX,
   NODE_VERTEX_COLOR_BUMP_DY,
+  NODE_AOV_START,
+  NODE_AOV_VALUE,
+  NODE_AOV_COLOR,
 } ShaderNodeType;
 
 typedef enum NodeAttributeType {