[Bf-blender-cvs] [123255be6b1] master: Fix T91994: Cycles crash when rendering on multiple devices

[Sergey Sharybin]

Commit: 123255be6b109963bc00fe5b3ea434ecedbde231
Author: Sergey Sharybin
Date:   Thu Oct 7 15:06:26 2021 +0200
Branches: master
https://developer.blender.org/rB123255be6b109963bc00fe5b3ea434ecedbde231

Fix T91994: Cycles crash when rendering on multiple devices

The overscan change from D12599 lacked proper handling of window
when slicing buffer for multiple devices.

===================================================================

M	intern/cycles/integrator/path_trace.cpp
M	intern/cycles/integrator/path_trace_work.cpp
M	intern/cycles/render/tile.h

===================================================================

diff --git a/intern/cycles/integrator/path_trace.cpp b/intern/cycles/integrator/path_trace.cpp
index 3ea5c3c64b8..9f3049c6484 100644
--- a/intern/cycles/integrator/path_trace.cpp
+++ b/intern/cycles/integrator/path_trace.cpp
@@ -234,42 +234,53 @@ template<typename Callback>
 static void foreach_sliced_buffer_params(const vector<unique_ptr<PathTraceWork>> &path_trace_works,
                                          const vector<WorkBalanceInfo> &work_balance_infos,
                                          const BufferParams &buffer_params,
+                                         const int overscan,
                                          const Callback &callback)
 {
   const int num_works = path_trace_works.size();
-  const int height = buffer_params.height;
+  const int window_height = buffer_params.window_height;
 
   int current_y = 0;
   for (int i = 0; i < num_works; ++i) {
     const double weight = work_balance_infos[i].weight;
-    const int slice_height = max(lround(height * weight), 1);
+    const int slice_window_full_y = buffer_params.full_y + buffer_params.window_y + current_y;
+    const int slice_window_height = max(lround(window_height * weight), 1);
 
     /* Disallow negative values to deal with situations when there are more compute devices than
      * scan-lines. */
-    const int remaining_height = max(0, height - current_y);
+    const int remaining_window_height = max(0, window_height - current_y);
+
+    BufferParams slice_params = buffer_params;
+
+    slice_params.full_y = max(slice_window_full_y - overscan, buffer_params.full_y);
+    slice_params.window_y = slice_window_full_y - slice_params.full_y;
 
-    BufferParams slide_params = buffer_params;
-    slide_params.full_y = buffer_params.full_y + current_y;
     if (i < num_works - 1) {
-      slide_params.height = min(slice_height, remaining_height);
+      slice_params.window_height = min(slice_window_height, remaining_window_height);
     }
     else {
-      slide_params.height = remaining_height;
+      slice_params.window_height = remaining_window_height;
     }
 
-    slide_params.update_offset_stride();
+    slice_params.height = slice_params.window_y + slice_params.window_height + overscan;
+    slice_params.height = min(slice_params.height,
+                              buffer_params.height + buffer_params.full_y - slice_params.full_y);
 
-    callback(path_trace_works[i].get(), slide_params);
+    slice_params.update_offset_stride();
 
-    current_y += slide_params.height;
+    callback(path_trace_works[i].get(), slice_params);
+
+    current_y += slice_params.window_height;
   }
 }
 
 void PathTrace::update_allocated_work_buffer_params()
 {
+  const int overscan = tile_manager_.get_tile_overscan();
   foreach_sliced_buffer_params(path_trace_works_,
                                work_balance_infos_,
                                big_tile_params_,
+                               overscan,
                                [](PathTraceWork *path_trace_work, const BufferParams &params) {
                                  RenderBuffers *buffers = path_trace_work->get_render_buffers();
                                  buffers->reset(params);
@@ -306,9 +317,12 @@ void PathTrace::update_effective_work_buffer_params(const RenderWork &render_wor
   const BufferParams scaled_big_tile_params = scale_buffer_params(big_tile_params_,
                                                                   resolution_divider);
 
+  const int overscan = tile_manager_.get_tile_overscan();
+
   foreach_sliced_buffer_params(path_trace_works_,
                                work_balance_infos_,
                                scaled_big_tile_params,
+                               overscan,
                                [&](PathTraceWork *path_trace_work, const BufferParams params) {
                                  path_trace_work->set_effective_buffer_params(
                                      scaled_full_params, scaled_big_tile_params, params);
diff --git a/intern/cycles/integrator/path_trace_work.cpp b/intern/cycles/integrator/path_trace_work.cpp
index f626beb0aaa..14e6f03aedc 100644
--- a/intern/cycles/integrator/path_trace_work.cpp
+++ b/intern/cycles/integrator/path_trace_work.cpp
@@ -134,7 +134,8 @@ void PathTraceWork::copy_from_denoised_render_buffers(const RenderBuffers *rende
 bool PathTraceWork::get_render_tile_pixels(const PassAccessor &pass_accessor,
                                            const PassAccessor::Destination &destination)
 {
-  const int offset_y = effective_buffer_params_.full_y - effective_big_tile_params_.full_y;
+  const int offset_y = (effective_buffer_params_.full_y + effective_buffer_params_.window_y) -
+                       (effective_big_tile_params_.full_y + effective_big_tile_params_.window_y);
   const int width = effective_buffer_params_.width;
 
   PassAccessor::Destination slice_destination = destination;
diff --git a/intern/cycles/render/tile.h b/intern/cycles/render/tile.h
index a13afaea64e..5872a9a8609 100644
--- a/intern/cycles/render/tile.h
+++ b/intern/cycles/render/tile.h
@@ -81,6 +81,11 @@ class TileManager {
     return tile_state_.num_tiles > 1;
   }
 
+  inline int get_tile_overscan() const
+  {
+    return overscan_;
+  }
+
   bool next();
   bool done();