Cycles: Add support for denoising in the viewport

The OptiX denoiser can be a great help when rendering in the viewport, since it is really fast
and needs few samples to produce convincing results. This patch therefore adds support for
using any Cycles denoiser in the viewport also (but only the OptiX one is selectable because
the NLM one is too slow to be usable currently). It also adds support for denoising on a
different device than rendering (so one can e.g. render with the CPU but denoise with OptiX).

Reviewed By: #cycles, brecht

Differential Revision: https://developer.blender.org/D6554

1 files changed, 26 insertions, 9 deletions

diff --git a/intern/cycles/blender/blender_session.cpp b/intern/cycles/blender/blender_session.cpp
index 1490348743e..2e7a72d8072 100644
--- a/intern/cycles/blender/blender_session.cpp
+++ b/intern/cycles/blender/blender_session.cpp
@@ -166,7 +166,7 @@ void BlenderSession::create_session()
 
   /* set buffer parameters */
   BufferParams buffer_params = BlenderSync::get_buffer_params(
-      b_render, b_v3d, b_rv3d, scene->camera, width, height);
+      b_scene, b_render, b_v3d, b_rv3d, scene->camera, width, height);
   session->reset(buffer_params, session_params.samples);
 
   b_engine.use_highlight_tiles(session_params.progressive_refine == false);
@@ -244,7 +244,7 @@ void BlenderSession::reset_session(BL::BlendData &b_data, BL::Depsgraph &b_depsg
   BL::SpaceView3D b_null_space_view3d(PointerRNA_NULL);
   BL::RegionView3D b_null_region_view3d(PointerRNA_NULL);
   BufferParams buffer_params = BlenderSync::get_buffer_params(
-      b_render, b_null_space_view3d, b_null_region_view3d, scene->camera, width, height);
+      b_scene, b_render, b_null_space_view3d, b_null_region_view3d, scene->camera, width, height);
   session->reset(buffer_params, session_params.samples);
 
   b_engine.use_highlight_tiles(session_params.progressive_refine == false);
@@ -460,7 +460,7 @@ void BlenderSession::render(BL::Depsgraph &b_depsgraph_)
   SessionParams session_params = BlenderSync::get_session_params(
       b_engine, b_userpref, b_scene, background);
   BufferParams buffer_params = BlenderSync::get_buffer_params(
-      b_render, b_v3d, b_rv3d, scene->camera, width, height);
+      b_scene, b_render, b_v3d, b_rv3d, scene->camera, width, height);
 
   /* render each layer */
   BL::ViewLayer b_view_layer = b_depsgraph.view_layer_eval();
@@ -706,7 +706,7 @@ void BlenderSession::bake(BL::Depsgraph &b_depsgraph_,
     SessionParams session_params = BlenderSync::get_session_params(
         b_engine, b_userpref, b_scene, background);
     BufferParams buffer_params = BlenderSync::get_buffer_params(
-        b_render, b_v3d, b_rv3d, scene->camera, width, height);
+        b_scene, b_render, b_v3d, b_rv3d, scene->camera, width, height);
 
     scene->bake_manager->set_shader_limit((size_t)b_engine.tile_x(), (size_t)b_engine.tile_y());
 
@@ -851,7 +851,6 @@ void BlenderSession::synchronize(BL::Depsgraph &b_depsgraph_)
   if (session->params.modified(session_params) || scene->params.modified(scene_params)) {
     free_session();
     create_session();
-    return;
   }
 
   /* increase samples, but never decrease */
@@ -886,10 +885,28 @@ void BlenderSession::synchronize(BL::Depsgraph &b_depsgraph_)
   else
     sync->sync_camera(b_render, b_camera_override, width, height, "");
 
+  /* get buffer parameters */
+  BufferParams buffer_params = BlenderSync::get_buffer_params(
+      b_scene, b_render, b_v3d, b_rv3d, scene->camera, width, height);
+
+  if (session_params.device.type != DEVICE_OPTIX &&
+      session_params.device.denoising_devices.empty()) {
+    /* cannot use OptiX denoising when it is not supported by the device. */
+    buffer_params.denoising_data_pass = false;
+  }
+  else {
+    session->set_denoising(buffer_params.denoising_data_pass, true);
+  }
+
+  if (scene->film->denoising_data_pass != buffer_params.denoising_data_pass) {
+    scene->film->denoising_data_pass = buffer_params.denoising_data_pass;
+
+    /* Force a scene and session reset below. */
+    scene->film->tag_update(scene);
+  }
+
   /* reset if needed */
   if (scene->need_reset()) {
-    BufferParams buffer_params = BlenderSync::get_buffer_params(
-        b_render, b_v3d, b_rv3d, scene->camera, width, height);
     session->reset(buffer_params, session_params.samples);
 
     /* After session reset, so device is not accessing image data anymore. */
@@ -956,7 +973,7 @@ bool BlenderSession::draw(int w, int h)
       SessionParams session_params = BlenderSync::get_session_params(
           b_engine, b_userpref, b_scene, background);
       BufferParams buffer_params = BlenderSync::get_buffer_params(
-          b_render, b_v3d, b_rv3d, scene->camera, width, height);
+          b_scene, b_render, b_v3d, b_rv3d, scene->camera, width, height);
       bool session_pause = BlenderSync::get_session_pause(b_scene, background);
 
       if (session_pause == false) {
@@ -974,7 +991,7 @@ bool BlenderSession::draw(int w, int h)
 
   /* draw */
   BufferParams buffer_params = BlenderSync::get_buffer_params(
-      b_render, b_v3d, b_rv3d, scene->camera, width, height);
+      b_scene, b_render, b_v3d, b_rv3d, scene->camera, width, height);
   DeviceDrawParams draw_params;
 
   if (session->params.display_buffer_linear) {