1 files changed, 26 insertions, 0 deletions
diff --git a/intern/cycles/scene/scene.cpp b/intern/cycles/scene/scene.cpp
index 2199b2351d0..359e2d8e2c3 100644
--- a/intern/cycles/scene/scene.cpp
+++ b/intern/cycles/scene/scene.cpp
@@ -489,7 +489,21 @@ void Scene::update_kernel_features()
   if (use_motion && camera->use_motion()) {
     kernel_features |= KERNEL_FEATURE_CAMERA_MOTION;
   }
+
+  /* Figure out whether the scene will use shader raytrace we need at least
+   * one caustic light, one caustic caster and one caustic receiver to use
+   * and enable the mnee code path. */
+  bool has_caustics_receiver = false;
+  bool has_caustics_caster = false;
+  bool has_caustics_light = false;
+
   foreach (Object *object, objects) {
+    if (object->get_is_caustics_caster()) {
+      has_caustics_caster = true;
+    }
+    else if (object->get_is_caustics_receiver()) {
+      has_caustics_receiver = true;
+    }
     Geometry *geom = object->get_geometry();
     if (use_motion) {
       if (object->use_motion() || geom->get_use_motion_blur()) {
@@ -518,6 +532,18 @@ void Scene::update_kernel_features()
     }
   }
 
+  foreach (Light *light, lights) {
+    if (light->get_use_caustics()) {
+      has_caustics_light = true;
+    }
+  }
+
+  dscene.data.integrator.use_caustics = false;
+  if (has_caustics_caster && has_caustics_receiver && has_caustics_light) {
+    dscene.data.integrator.use_caustics = true;
+    kernel_features |= KERNEL_FEATURE_NODE_RAYTRACE;
+  }
+
   if (bake_manager->get_baking()) {
     kernel_features |= KERNEL_FEATURE_BAKING;
   }