Cycles: Replace __MAX_CLOSURE__ build option with runtime integrator variable

Goal is to reduce OpenCL kernel recompilations.

Currently viewport renders are still set to use 64 closures as this seems to
be faster and we don't want to cause a performance regression there. Needs
to be investigated.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2775

1 files changed, 10 insertions, 2 deletions

diff --git a/intern/cycles/render/session.cpp b/intern/cycles/render/session.cpp
index 74cfd02e1a4..e8d9558c38d 100644
--- a/intern/cycles/render/session.cpp
+++ b/intern/cycles/render/session.cpp
@@ -642,13 +642,11 @@ DeviceRequestedFeatures Session::get_requested_device_features()
 	DeviceRequestedFeatures requested_features;
 	requested_features.experimental = params.experimental;
 
-	requested_features.max_closure = get_max_closure_count();
 	scene->shader_manager->get_requested_features(
 	        scene,
 	        &requested_features);
 	if(!params.background) {
 		/* Avoid too much re-compilations for viewport render. */
-		requested_features.max_closure = 64;
 		requested_features.max_nodes_group = NODE_GROUP_LEVEL_MAX;
 		requested_features.nodes_features = NODE_FEATURE_ALL;
 	}
@@ -858,6 +856,16 @@ void Session::update_scene()
 	if(scene->need_update()) {
 		load_kernels(false);
 
+		/* Update max_closures. */
+		KernelIntegrator *kintegrator = &scene->dscene.data.integrator;
+		if(params.background) {
+			kintegrator->max_closures = get_max_closure_count();
+		}
+		else {
+			/* Currently viewport render is faster with higher max_closures, needs investigating. */
+			kintegrator->max_closures = 64;
+		}
+
 		progress.set_status("Updating Scene");
 		MEM_GUARDED_CALL(&progress, scene->device_update, device, progress);
 	}