Fix T91426: don't display outdated denoised result when increasing samples

3 files changed, 33 insertions, 18 deletions

diff --git a/intern/cycles/integrator/path_trace.cpp b/intern/cycles/integrator/path_trace.cpp
index 856e90697dc..6973a86daac 100644
--- a/intern/cycles/integrator/path_trace.cpp
+++ b/intern/cycles/integrator/path_trace.cpp
@@ -522,7 +522,7 @@ void PathTrace::draw()
 
 void PathTrace::update_display(const RenderWork &render_work)
 {
-  if (!render_work.update_display) {
+  if (!render_work.display.update) {
     return;
   }
 
@@ -561,8 +561,10 @@ void PathTrace::update_display(const RenderWork &render_work)
     return;
   }
 
-  const PassMode pass_mode = render_state_.has_denoised_result ? PassMode::DENOISED :
-                                                                 PassMode::NOISY;
+  const PassMode pass_mode = render_work.display.use_denoised_result &&
+                                     render_state_.has_denoised_result ?
+                                 PassMode::DENOISED :
+                                 PassMode::NOISY;
 
   /* TODO(sergey): When using multi-device rendering map the GPUDisplay once and copy data from all
    * works in parallel. */
diff --git a/intern/cycles/integrator/render_scheduler.cpp b/intern/cycles/integrator/render_scheduler.cpp
index 45a5f4b8bd5..7a842f2e4cd 100644
--- a/intern/cycles/integrator/render_scheduler.cpp
+++ b/intern/cycles/integrator/render_scheduler.cpp
@@ -185,10 +185,11 @@ bool RenderScheduler::render_work_reschedule_on_converge(RenderWork &render_work
 
   state_.path_trace_finished = true;
 
-  bool denoiser_delayed;
-  render_work.tile.denoise = work_need_denoise(denoiser_delayed);
+  bool denoiser_delayed, denoiser_ready_to_display;
+  render_work.tile.denoise = work_need_denoise(denoiser_delayed, denoiser_ready_to_display);
 
-  render_work.update_display = work_need_update_display(denoiser_delayed);
+  render_work.display.update = work_need_update_display(denoiser_delayed);
+  render_work.display.use_denoised_result = denoiser_ready_to_display;
 
   return false;
 }
@@ -261,7 +262,7 @@ void RenderScheduler::render_work_reschedule_on_cancel(RenderWork &render_work)
    * buffers. And the buffers might have been freed from the device, so display update is not
    * possible. */
   if (has_rendered_samples && !state_.full_frame_was_written) {
-    render_work.update_display = true;
+    render_work.display.update = true;
   }
 }
 
@@ -327,12 +328,13 @@ RenderWork RenderScheduler::get_render_work()
   render_work.adaptive_sampling.threshold = work_adaptive_threshold();
   render_work.adaptive_sampling.reset = false;
 
-  bool denoiser_delayed;
-  render_work.tile.denoise = work_need_denoise(denoiser_delayed);
+  bool denoiser_delayed, denoiser_ready_to_display;
+  render_work.tile.denoise = work_need_denoise(denoiser_delayed, denoiser_ready_to_display);
 
   render_work.tile.write = done();
 
-  render_work.update_display = work_need_update_display(denoiser_delayed);
+  render_work.display.update = work_need_update_display(denoiser_delayed);
+  render_work.display.use_denoised_result = denoiser_ready_to_display;
 
   if (done()) {
     set_postprocess_render_work(&render_work);
@@ -354,7 +356,7 @@ void RenderScheduler::update_state_for_render_work(const RenderWork &render_work
 
   /* A fallback display update time, for the case there is an error of display update, or when
    * there is no display at all. */
-  if (render_work.update_display) {
+  if (render_work.display.update) {
     state_.last_display_update_time = time_now;
     state_.last_display_update_sample = state_.num_rendered_samples;
   }
@@ -389,7 +391,7 @@ bool RenderScheduler::set_postprocess_render_work(RenderWork *render_work)
   }
 
   if (any_scheduled) {
-    render_work->update_display = true;
+    render_work->display.update = true;
   }
 
   return any_scheduled;
@@ -870,9 +872,10 @@ float RenderScheduler::work_adaptive_threshold() const
   return max(state_.adaptive_sampling_threshold, adaptive_sampling_.threshold);
 }
 
-bool RenderScheduler::work_need_denoise(bool &delayed)
+bool RenderScheduler::work_need_denoise(bool &delayed, bool &ready_to_display)
 {
   delayed = false;
+  ready_to_display = true;
 
   if (!denoiser_params_.use) {
     /* Denoising is disabled, no need to scheduler work for it. */
@@ -907,6 +910,7 @@ bool RenderScheduler::work_need_denoise(bool &delayed)
 
   /* Do not denoise until the sample at which denoising should start is reached. */
   if (num_samples_finished < denoiser_params_.start_sample) {
+    ready_to_display = false;
     return false;
   }
 
diff --git a/intern/cycles/integrator/render_scheduler.h b/intern/cycles/integrator/render_scheduler.h
index 9c9e758c8c3..9c3b6888f83 100644
--- a/intern/cycles/integrator/render_scheduler.h
+++ b/intern/cycles/integrator/render_scheduler.h
@@ -75,8 +75,14 @@ class RenderWork {
     bool denoise = false;
   } full;
 
-  /* Display which is used to visualize render result is to be updated for the new render. */
-  bool update_display = false;
+  /* Display which is used to visualize render result. */
+  struct {
+    /* Display needs to be updated for the new render. */
+    bool update = false;
+
+    /* Display can use denoised result if available. */
+    bool use_denoised_result = true;
+  } display;
 
   /* Re-balance multi-device scheduling after rendering this work.
    * Note that the scheduler does not know anything abouce devices, so if there is only a single
@@ -87,7 +93,7 @@ class RenderWork {
    * work. */
   inline operator bool() const
   {
-    return path_trace.num_samples || adaptive_sampling.filter || update_display || tile.denoise ||
+    return path_trace.num_samples || adaptive_sampling.filter || display.update || tile.denoise ||
            tile.write || full.write || full.denoise;
   }
 };
@@ -253,8 +259,11 @@ class RenderScheduler {
    * often.
    *
    * The delayed will be true when the denoiser is configured for use, but it was delayed for a
-   * later sample, to reduce overhead. */
-  bool work_need_denoise(bool &delayed);
+   * later sample, to reduce overhead.
+   *
+   * ready_to_display will be false if we may have a denoised result that is outdated due to
+   * increased samples. */
+  bool work_need_denoise(bool &delayed, bool &ready_to_display);
 
   /* Check whether current work need to update display.
    *