Cycles: Initial work towards selective nodes support compilation

The goal is to be able to compile kernel with nodes which are actually needed
to render current scene, hence improving performance of the kernel,

The idea is:

- Have few node groups, starting with a group which contains nodes are used
  really often, and then couple of groups which will be extension of this one.

- Have feature-based nodes disabling, so it's possible to disable nodes related
  to features which are not used with the currently used nodes group.

This commit only lays down needed routines for this approach, actual split will
happen later after gathering statistics from bunch of production scenes.

1 files changed, 17 insertions, 0 deletions

diff --git a/intern/cycles/kernel/svm/svm_types.h b/intern/cycles/kernel/svm/svm_types.h
index 848c16be327..4f2117a605b 100644
--- a/intern/cycles/kernel/svm/svm_types.h
+++ b/intern/cycles/kernel/svm/svm_types.h
@@ -28,6 +28,23 @@ CCL_NAMESPACE_BEGIN
 
 /* Nodes */
 
+/* Known frequencies of used nodes, used for selective nodes compilation
+ * in the kernel. Currently only affects split OpenCL kernel.
+ *
+ * Keep as defines so it's easy to check which nodes are to be compiled
+ * from preprocessor.
+ *
+ * Lower the number of group more often the node is used.
+ */
+#define NODE_GROUP_LEVEL_0    0
+#define NODE_GROUP_LEVEL_1    1
+#define NODE_GROUP_LEVEL_2    2
+#define NODE_GROUP_LEVEL_MAX  NODE_GROUP_LEVEL_2
+
+#define NODE_FEATURE_VOLUME     (1 << 0)
+#define NODE_FEATURE_HAIR       (1 << 1)
+#define NODE_FEATURE_ALL        (NODE_FEATURE_VOLUME|NODE_FEATURE_HAIR)
+
 typedef enum NodeType {
 	NODE_END = 0,
 	NODE_CLOSURE_BSDF,